Thursday, December 27, 2018

Using LibROSA python module.

This python module named LibROSA is a python package for music and audio analysis and provides the building blocks necessary to create music information retrieval systems.
C:\Python364>cd Scripts
C:\Python364\Scripts>pip install librosa
Collecting librosa
Successfully installed audioread-2.1.6 joblib-0.13.0 librosa-0.6.2 llvmlite-0.26.0 numba-0.41.0 resampy-0.2.1 
Let's create one waveform and a spectrogram with this python module.
The waveform (for sound) the term describes a depiction of the pattern of sound pressure variation (or amplitude) in the time domain.
A spectrogram (known also like sonographs, voiceprints, or voicegrams) is a visual representation of the spectrum of frequencies of sound or other signals as they vary with time.
I used a free WAV file sound from here.
The result of the waveform and spectrogram for that audio file is shown into next screenshots:

My example show first the waveform and you need to close the it to see the spectrogram.
Let's see the source code of this example:
import librosa
import librosa.display
import matplotlib.pyplot as plt
plt.figure(figsize=(14, 5))
path = "merry_christmas.wav"
out,samples = librosa.load(path)
print(out.shape, samples)
librosa.display.waveplot(out, sr=samples)
stft_array = librosa.stft(out)
stft_array_db = librosa.amplitude_to_db(abs(stft_array))
librosa.display.specshow(stft_array_db,sr=samples,x_axis='time', y_axis='hz')

Tuesday, December 25, 2018

Using python modules: mayavi and moviepy - part 001.

This is a simple example with two modules named: mayavi and moviepy.
Let's see the introduction of these python modules:
Mayavi2 is a general purpose, cross-platform tool for 3-D scientific data visualization. Its features include:

  • Visualization of scalar, vector and tensor data in 2 and 3 dimensions.
  • Easy scriptability using Python.
  • Easy extendibility via custom sources, modules, and data filters.
  • Reading several file formats: VTK (legacy and XML), PLOT3D, etc.
  • Saving of visualizations.
  • Saving rendered visualization in a variety of image formats.
  • Convenient functionality for rapid scientific plotting via mlab
MoviePy is a Python module for video editing, which can be used for basic operations (like cuts, concatenations, title insertions), video compositing (a.k.a. non-linear editing), video processing, or to create advanced effects. It can read and write the most common video formats, including GIF.
The installation with pip3.6 tool:
C:\Python364\Scripts>pip3.6.exe install mayavi
Requirement already satisfied: mayavi in c:\python364\lib\site-packages (4.6.2)
C:\Python364\Scripts>pip3.6.exe install moviepy
Collecting moviepy
Installing collected packages: tqdm, moviepy
Successfully installed moviepy- tqdm-4.28.1
Let's create a simple example with these python modules.
First example:
Python 3.6.4 (v3.6.4:d48eceb, Dec 19 2017, 06:54:40) [MSC v.1900 64 bit (AMD64)]
 on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import mayavi.mlab as mlab
>>> f = mlab.gcf()
>>> f.scene._lift()
I choose the most common filter math function: the sinc function, known as sine cardinal:
In signal processing, a sinc filter is an idealized filter that removes all frequency components above a given cutoff frequency, without affecting lower frequencies, and has linear phase response. The filter's impulse response is a sinc function in the time domain, and its frequency response is a rectangular function.
I create the example to show you a sinc function by time.
This is my output (is not the result of the frequency response of the Fourier transform of the rectangular function).

Let's see the source code:
# import python modules
import numpy as np
import mayavi.mlab as mlab
import moviepy.editor as mpy
# duration of the animation in seconds 
duration= 2
# create the grid of points for x and y
x, y = np.mgrid[-30:30:100j, -30:30:100j]
# create the size figure
fig = mlab.figure(size=(640,480), bgcolor=(1,1,1))
# create the plane surface
r = np.sqrt(x**2 + y**2)
# this fix issue
fig = mlab.gcf()
# create all frames 
def make_frame(t):
    # clear the area 
    #blend surface by z over time t step is 0.05
    z = np.sin(r*t)/r
    # create surface, warp_scale='auto')
    return mlab.screenshot(antialiased=True)
# create animation movie clip
animation = mpy.VideoClip(make_frame,duration=duration)
# write file like a GIF 
animation.write_gif("sinc.gif", fps=20)

Monday, December 24, 2018

Python Qt5 - most simple QTreeWidget - part 001.

The QTreeWidget is more complex in order to accomplish a simple development issue.
Today, I will show you how is the first step to start it.
This simple example will follow these goals:
  • create a simple QTreeWidget;
  • use the most simple way to do that;
  • do not use the class object;
  • show files and folders;
The example do not have any feature for and show my C drive:
  • filter, sort and drag and drop;
The result of this example:

Saturday, December 22, 2018

Using pytorch - the final of story.

Let's continue our story with the child and the gift.
The child saw the gift and his first thought was the desire to know.
The basic forming unit of a neural network is a perceptron.
He saw that he was not too big and his eyes lit up.
To compute the output will multiply input with respective weights and compare with a threshold value.
Each perceptron also has a bias which can be thought of as how much flexible the perceptron is.
This process is of evolving a perceptron to what a now called an artificial neuron.
The next step is the artificial network and is all artificial neuron and edges between.
He touched him in the corners and put his hand on his surface.
The activation function is mostly used to make a non-linear transformation which allows us to fit nonlinear hypotheses or to estimate the complex functions.
He began to understand that he had a special and complex form.
This artificial network is built from start to end from:
  • Input Layer an X as an input matrix;
  • Hidden Layers a matrix dot product of input and weights assigned to edges between the input and hidden layer, then add biases of the hidden layer neurons to respective inputs and use this to update all weights at the output and hidden layer to use update biases at the output and hidden layer.
  • Output Layer an y as an output matrix;
Without too much thoughts he began to break out of the gift in the order in which he touched it.
This weight and bias of the updating process are known as back propagation.
To computed the output and this process is known as forward propagation.
Several moves were enough to complete the opening of the gift.
He looked and understood that the size of the gift is smaller, but the gift was thankful to him.
This forward and back propagation iteration is known as one training iteration named epoch.
The next example I created from an old example I saw on the internet and is the most simple way to show you the steps from this last part of the story:
##use an neural network in pytorch
import torch

#an input array
X = torch.Tensor([[1,0,1],[0,1,1],[0,1,0]])

#the output
y = torch.Tensor([[1],[1],[0]])

#the Sigmoid Function
def sigmoid (x):
  return 1/(1 + torch.exp(-x))

#the derivative of Sigmoid Function
def derivatives_sigmoid(x):
  return x * (1 - x)

#set the variable initialization
epoch=1000 #training iterations is epoch
lr=0.1 #learning rate value
inputlayer_neurons = X.shape[1] #number of features in data set
hiddenlayer_neurons = 3 #number of hidden layers neurons
output_neurons = 1 #number of neurons at output layer

#weight and bias initialization
wh=torch.randn(inputlayer_neurons, hiddenlayer_neurons).type(torch.FloatTensor)
print("weigt = ", wh)
bh=torch.randn(1, hiddenlayer_neurons).type(torch.FloatTensor)
print("bias = ", bh)
wout=torch.randn(hiddenlayer_neurons, output_neurons)
print("wout = ", wout)
bout=torch.randn(1, output_neurons)
print("bout = ", bout)

for i in range(epoch):

  #Forward Propogation
  hidden_layer_input1 =, wh)
  hidden_layer_input = hidden_layer_input1 + bh
  hidden_layer_activations = sigmoid(hidden_layer_input)
  output_layer_input1 =, wout)
  output_layer_input = output_layer_input1 + bout
  output = sigmoid(output_layer_input1)

  E = y-output
  slope_output_layer = derivatives_sigmoid(output)
  slope_hidden_layer = derivatives_sigmoid(hidden_layer_activations)
  d_output = E * slope_output_layer
  Error_at_hidden_layer =, wout.t())
  d_hiddenlayer = Error_at_hidden_layer * slope_hidden_layer
  wout +=, d_output) *lr
  bout += d_output.sum() *lr
  wh +=, d_hiddenlayer) *lr
  bh += d_output.sum() *lr
print('actual :\n', y, '\n')
print('predicted :\n', output)
The result is for 100 and 1000 epoch value and show us how close is the actual input (1,1,0) to the predicted results.
See also the weight and bias initialization of the artificial network is created random by torch.randn.
If I added this in my story it would sound like this:
The child's thoughts began to flinch in wanting to finish faster and find the gift.
weigt =  tensor([[-0.9364,  0.4214,  0.2473],
        [-1.0382,  2.0838, -1.2670],
        [ 1.2821, -0.7776, -1.8969]])
bias =  tensor([[-0.3604, -0.8943,  0.3786]])
wout =  tensor([[-0.5408],
        [ 1.3174],
bout =  tensor([[-0.4228]])
actual :

predicted :

weigt =  tensor([[ 1.2993,  1.5142, -1.6325],
        [ 0.0621, -0.5370,  0.1480],
        [ 1.5673, -0.2273, -0.3698]])
bias =  tensor([[-2.0730, -1.2494,  0.2484]])
wout =  tensor([[ 0.6642],
        [ 1.6692],
bout =  tensor([[0.3340]])
actual :

predicted :

Friday, December 21, 2018

Python Qt5 - simple draw with QPainter.

Using the QPainter is more complex than a simple example.
I try to create a simple example in order to have a good look at how can be used.
The main goal was to understand how can have the basic elements of QPainter.
The result of my example is this:

Here is my example with all commented lines for a good approach:
import sys 
from PyQt5 import QtGui, QtWidgets 
from PyQt5.QtGui import QPainter, QBrush, QColor
from PyQt5.QtCore import Qt, QPoint 
class My_QPainter(QtWidgets.QWidget): 
    def paintEvent(self, event): 
        # create custom QPainter
        my_painter = QtGui.QPainter() 
        # start and set my_painter
        my_painter.setRenderHint(my_painter.TextAntialiasing, True)
        my_painter.setRenderHint(my_painter.Antialiasing, True)
        #set color for pen by RGB
        # draw a text on fixed coordinates
        my_painter.drawText(220,100, "Text at 220, 100 fixed coordinates") 
        # draw a text in the centre of my_painter   
        my_painter.drawText(event.rect(), Qt.AlignCenter, "Text centerd in the drawing area") 
        #set color for pen by Qt color  
        my_painter.setPen(QtGui.QPen(, 1)) 
        # draw a ellipse
        # set color for pen by property
        my_painter.setPen(QtGui.QPen(, 3, join = Qt.MiterJoin)) 
        # draw a rectangle
        # set color for pen by Qt color 
        my_painter.setPen(QtGui.QPen(, 2))
        # set brush 
        my_brush = QBrush(QColor(33, 33, 100, 255), Qt.DiagCrossPattern)
        # draw a rectangle and fill with the brush 
        my_painter.drawRect(300, 300,180, 180)
# create application  
app = QtWidgets.QApplication(sys.argv) 
# create the window application from class
window = My_QPainter() 
# show the window 
# default exit 

Thursday, December 20, 2018

Python 3.6.4 : Learning OpenCV - centroids.

Today I was a little lazy.
I studied a little on the internet.
The last aspect was related to centroids.
An example I studied before TV news was from this webpage.
About centroid you can read here.
The result of the source code from a video with Simona Halep.

Tuesday, December 18, 2018

Python Qt5 - complex QML file.

Today, I will show you how to have a more complex custom application with PyQt5 and QML file.
You need to create into your python folder a new folder named QMLCustom.
Into this file create two python files named: and
The __init__ will be an empty file.
Into your python folder installation (where you create the QMLCustom folder), create a new QML_custom.qml file.
The QML_custom.qml file will have this:
import QtQuick 2.0
import SDK 1.0
import QtQuick.Layouts 1.1

Rectangle {
    id: appwnd
    visible: true
    width: 640
    height: 480

    property int columns : 2
    property int rows : 2

    Rectangle {
        anchors.fill: parent
        color: "#00f"

    GridView {
        id: grid
        anchors.fill: parent
        cellWidth: Math.max(width/2, height/2);
        cellHeight: Math.max(width/2, height/2)
        model: dashModel
        delegate : Rectangle {
            Layout.alignment: Layout.Center
            width: grid.cellWidth
            height: grid.cellHeight
            color: "#0ff"
            border.color: "#fff"
            border.width: 10

            Text {
                id: name
                anchors.horizontalCenter: parent.horizontalCenter
                anchors.bottom: parent.bottom
                anchors.topMargin: 15
                width: parent.width 
                height: parent.height
                textFont {
                    family: "Halvetica"
                    italic: false
                suffixText: suffix

        onWidthChanged: {
            grid.cellWidth = grid.width/appwnd.columns;

        onHeightChanged: {
            grid.cellHeight = grid.height/appwnd.rows

    ListModel {
        id: dashModel
        ListElement {
            tagName: "Text"
            suffix: "First text"
        ListElement {
            tagName: "Text"
            suffix: "Next text"
If you read this you will see the qml type file has two imports and a text.
The imports are used to load it and the text file is used to describe what we need.
In this case is created a Rectangle, GridView and one ListModel with two ListElement.
All of this part will be a link to the file.
For example: follow the suffixText from qml file suffixText: suffix into file (decorator def suffixText(self, text)).
Into the QMLCustom folder you need to fill the with this:
import PyQt5
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
from PyQt5.QtCore import pyqtProperty, pyqtSignal, pyqtSlot
from PyQt5.QtQuick import QQuickPaintedItem, QQuickItem
from PyQt5.QtGui import QPainter
from PyQt5 import QtCore

class QMLCustom(QQuickPaintedItem):
    class DialType():
        FullDial = 0
        MinToMax = 1
        NoDial = 2
    sizeChanged = pyqtSignal()
    valueChanged = pyqtSignal()
    backgroundColorChanged = pyqtSignal()
    textColorChanged = pyqtSignal()
    suffixTextChanged = pyqtSignal()
    showTextChanged = pyqtSignal()
    textFontChanged = pyqtSignal()

    def __init__(self, parent=None):
        super(QMLCustom, self).__init__(parent)


        self._Size = 100
        self._DialWidth = 15
        self._SuffixText = ""
        self._BackgroundColor = Qt.transparent
        self._TextColor = QColor(0, 0, 0)
        self._ShowText = True
        self._TextFont = QFont()

    def paint(self, painter):

        size = min(self.width(), self.height())       
        rect = QRectF(0, 0, self.width(), self.height()) 
        offset = self._DialWidth / 2
        if self._ShowText:
            painter.drawText(rect.adjusted(offset, offset, -offset, -offset), Qt.AlignCenter, self._SuffixText)
            painter.drawText(rect.adjusted(offset, offset, -offset, -offset), Qt.AlignCenter, self._SuffixText)

    @QtCore.pyqtProperty(str, notify=sizeChanged)
    def size(self):
        return self._Size

    def size(self, size):
        if self._Size == size:
        self._Size = size

    @QtCore.pyqtProperty(float, notify=valueChanged)
    def value(self):
        return self._Value

    def value(self, value):
        if self._Value == value:
        self._Value = value

    @QtCore.pyqtProperty(QColor, notify=backgroundColorChanged)
    def backgroundColor(self):
        return self._BackgroundColor

    def backgroundColor(self, color):
        if self._BackgroundColor == color:
        self._BackgroundColor = color

    @QtCore.pyqtProperty(QColor, notify=textColorChanged)
    def textColor(self):
        return self._TextColor

    def textColor(self, color):
        if self._TextColor == color:
        self._TextColor = color

    @QtCore.pyqtProperty(str, notify=suffixTextChanged)
    def suffixText(self):
        return self._SuffixText

    def suffixText(self, text):
        if self._SuffixText == text:
        self._SuffixText = text

    @QtCore.pyqtProperty(str, notify=showTextChanged)
    def showText(self):
        return self._ShowText

    def showText(self, show):
        if self._ShowText == show:
        self._ShowText = show

    @QtCore.pyqtProperty(QFont, notify=textFontChanged)
    def textFont(self):
        return self._TextFont

    def textFont(self, font):
        if self._TextFont == font:
        self._TextFont = font
This is a base python module that allows you to use the qml file and show it into your application.
The use a class (with pyqtSignal and paint to link all data with decorators) to be used into your application.
This can be a little difficult to follow but if you deal with a tool like QtCreator editor you will understand how this integrated GUI layout and forms designer with this script.
The last part is more simple and is the application.
This script uses both the custom python module QMLCustom and the qml file.
Create a python file into your folder python installation fill with the next script and run it:
import sys
import os
import subprocess

from QMLCustom.QMLCustom import QMLCustom

from PyQt5.QtCore import QUrl, Qt, QObject, pyqtSignal, pyqtSlot
from PyQt5.QtGui import QGuiApplication, QCursor
from PyQt5.QtQuick import QQuickView
from PyQt5.QtQml import qmlRegisterType
from OpenGL import GLU

class App(QGuiApplication):
 def __init__(self, argv):
  super(App, self).__init__(argv)

if __name__ == '__main__':
  app = App(sys.argv)
  qmlRegisterType(QMLCustom, "SDK", 1,0, "Text")

  view = QQuickView()
  ctxt = view.rootContext()
  ret = app.exec_()

 except Exception as e:
  print (e)
The result is this:

Python Qt5 - application with QML file.

The PyQt5 includes QML as a means of declaratively describing a user interface and is possible to write complete standalone QML applications.
Using QML file is different from the versions PyQt5 and old PyQt4.
Using this type of application can let you solve custom and style application.
I create a simple example but can create your python module with a class with new type of style.
This can be used with qmlRegisterType for your new python class type.
Let's see the example:
The main python file:
from PyQt5.QtNetwork import *
from PyQt5.QtQml import *
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *

class MainWin(object):
    def __init__(self):
        self.eng = QQmlApplicationEngine()
        win = self.eng.rootObjects()[0]  

if __name__ == '__main__':
    import sys
    App = QApplication(sys.argv)
    Win = MainWin()
The QML file:
import QtQuick 2.2
import QtQuick.Controls 1.0
ApplicationWindow {
    id: main
    width: 640
    height: 480
    color: 'blue'
The result is a blue window.

Monday, December 17, 2018

Using pytorch - another way.

Yes. I used pytorch and is working well. Is not perfect the GitHub come every day with a full stack of issues.
Let's continue this series with another step: torchvision.
If you take a closer look at that gift, you will see that it comes with a special label that can really help us.
This label is a named torchvision.
The torchvision python module is a package consists of popular datasets, model architectures, and common image transformations for computer vision.
Most operations pass through filters and date already recognized.
  • torchvision.datasets: (MNIST,Fashion-MNIST,EMNIST,COCO,LSUN,ImageFolder,DatasetFolder,Imagenet-12,CIFAR,STL10,SVHN,PhotoTour,SBU,Flickr,VOC)
  • torchvision.models: (Alexnet,VGG,ResNet,SqueezeNet,DenseNet,Inception v3)
  • torchvision.transforms: (Transforms on PIL Image,Transforms on torch.*Tensor,Conversion Transforms,Generic Transforms,Functional Transforms)
  • torchvision.utils
This part of the gift help you to load and prepare dataset but into certain order.
Using this special label, we will be able to use the gift-breaking information.
Let's see the example:
Python 3.6.4 (v3.6.4:d48eceb, Dec 19 2017, 06:54:40) [MSC v.1900 64 bit (AMD64)]
 on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import torchvision
>>> import torchvision.transforms as transforms
>>> transform = transforms.Compose(
...     [transforms.ToTensor(),
...      transforms.Normalize((0.5, 0.5, 0.5), (0.5, 0.5, 0.5))])
>>> trainset = torchvision.datasets.CIFAR10(root='./data', train=True,download=T
rue, transform=transform)
Downloading to ./data\ci
You will ask me: How is this special gift label linked?
In this way:
>>> import torch
>>> trainloader =, batch_size=4,shuffle=Tru
e, num_workers=2)
Let's take a closer look at the information in the special label.
>>> print(trainset)
Dataset CIFAR10
    Number of datapoints: 50000
    Split: train
    Root Location: ./data
    Transforms (if any): Compose(
                             Normalize(mean=(0.5, 0.5, 0.5), std=(0.5, 0.5, 0.5)
    Target Transforms (if any): None
>>> print(dir(trainset))
['__add__', '__class__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq_
_', '__format__', '__ge__', '__getattribute__', '__getitem__', '__gt__', '__hash
__', '__init__', '__init_subclass__', '__le__', '__len__', '__lt__', '__module__
', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__'
, '__sizeof__', '__str__', '__subclasshook__', '__weakref__', '_check_integrity'
, 'base_folder', 'download', 'filename', 'root', 'target_transform', 'test_list'
, 'tgz_md5', 'train', 'train_data', 'train_labels', 'train_list', 'transform', '
Let's look more closely at the information that can be used by the gift with the special label.
>>> print(trainloader)

>>> print(dir(trainloader))
['_DataLoader__initialized', '__class__', '__delattr__', '__dict__', '__dir__',
'__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__ha
sh__', '__init__', '__init_subclass__', '__iter__', '__le__', '__len__', '__lt__
', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__',
 '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', 'bat
ch_sampler', 'batch_size', 'collate_fn', 'dataset', 'drop_last', 'num_workers',
'pin_memory', 'sampler', 'timeout', 'worker_init_fn']
Beware, CIFAR10 is just one of the training databases.
About the CIFAR-10 dataset, that consists of 60,000 32x32 color images in 10 classes, with 6,000 images per class.
There are 50,000 training images (5,000 per class) and 10,000 test images.

Sunday, December 16, 2018

Fix errors when write files.

The python is a very versatile programming language.
The tutorial for today is about:
  • check the type of variables;
  • see the list error of writelines with the list output;
  • fix errors for writelines;
One good example for some errors can be this:
>>> file.writelines(paragraphs)
Traceback (most recent call last):
  File "", line 1, in 
TypeError: a bytes-like object is required, not 'str'
>>> file.writelines(paragraphs.decode('utf-8'))
Traceback (most recent call last):
  File "", line 1, in 
AttributeError: 'list' object has no attribute 'decode'
Is a common issue for list and writing file.
The result of paragraphs is a list, see:
>>> type(paragraphs)
The list can be write with te writelines into the file like this:
>>> file = open("out.txt","wb")
>>> file.writelines([word.encode('utf-8') for word in paragraphs])
The file is a open file variable and the paragraphs is a list.

Thursday, December 13, 2018

Using pytorch - a simpler perspective.

Suppose this module PyTorch is a data extravagance circuit that allows us to filter information several times, and we can decide each time we decide the final result.
A simpler perspective of how to work with PyTorch can be explained by a simple example.
It's like a Christmas baby (PyTorch) that opens a multi-packed gift until it gets the final product - the desired gift.
The opening operations of the package involve smart moves called: forward and backward passes.
The child's feedback can be called: loss and backpropagate.
In this case, the child will try to remove from his package until he is satisfied and will not be lost (loss and backpropagate functions).
To compute the backward pass for a gradient and every time we backpropagate the gradient from a variable, the gradient is accumulative instead of being reset and replaced (most of networks designs call backward multiple times).
PyTorch comes with many loss functions.
Most of examples code create a mean square error loss function and later backpropagate the gradients based on the loss.
Will you ask me if the gift is shaped? I can tell you that the gift can contain from Verge à Saint-Nicolas (unidimensional) to complex (multidimensional) structures - the most simplistic and worn out is the square one (two-dimensional matrix).
This gift is packed with magic in mathematical functions which allows the child to understand what is in the gift.
But the child is more special. He recognizes forms (matrices, shapes, simple formulas) and this allows him to open parts of the gift.
El poate roti acesta parti din cadou (mm).
The mm is a matrix multiplication.
He can see the corners he can get from the gift.
ReLU stands for "rectified linear unit" and is a type of activation function.
Mathematically, it is defined as y = max(0, x).
He can see which parts of the gift are bigger or smaller so he can understand the gift.
This clamp function clamps all elements in input into the returns[ min, max ] and returns a resulting tensor:
The clamp should only affect gradients for values outside the min and max range.
The pow function power with the exponent.
The clone returns a copy of the self tensor. The copy has the same size and data type as self.
A common example is: clamp(min=0) is exactly ReLU().
PyTorch provides ReLU and its variants through the torch.nn module.
If you run the program to look at the output, you will understand that the child has only five operations left and is already pleased with the way the gift result.
The source code is based on one example from here:
import torch 
dtype = torch.float
device = torch.device("cpu")
batch,input,hidden,output = 2,10,2,5
x = torch.randn(batch,input,device=device,dtype=dtype)
y = torch.randn(hidden,output,device=device,dtype=dtype)
w1 = torch.randn(input,hidden,device=device,dtype=dtype)
w2 = torch.randn(hidden,output,device=device,dtype=dtype)

l_r = 1e-6
for t in range(5):
 h =
 h_r = h.clamp(min=0)
 y_p =
 loss = (y_p - y).pow(2).sum().item()
 g_y_p = 2.0 * (y_p -y)
 g_w2 = h_r.t().mm(g_y_p)
 g_h_r =
 g_h = g_h_r.clone()
 g_h[h<0 -="l_r" 0="" g_w1="" g_w2="" n="" print="" w1=",w1," w2=",w2,">
The child's result after five operations.
t= 4 loss= 25.40263557434082

w1= tensor([[ 1.5933,  0.3818],
        [-1.0043, -1.3362],
        [ 0.5841, -1.9811],
        [ 2.3483,  0.5748],
        [ 0.5904, -0.2521],
        [-0.6612,  2.7945],
        [ 0.4841, -0.5894],
        [-1.4434, -0.1421],
        [-1.2712, -1.4269],
        [ 0.7929,  0.2040]]) w2= tensor([[ 1.7389,  0.4337,  0.4557,  1.3704,  0
        [ 0.2937,  0.0212, -0.4604, -1.0564, -1.5403]])

Wednesday, December 12, 2018

Using pytorch - install it on Windows OS.

A few days ago I install the pytorch on my Windows 8.1 OS and today I will able to install on Fedora 29 distro.
I will try to make a series of pytorch tutorials with Linux and Windows OS on my blogs.
If you want to install it on Fedora 29 you need to follow my Fedora blog post.
For installation on Windows OS, you can read the official webpage.
Because I don't have a new CUDA GPU, the only one video card is an NVIDIA video card 740M on my laptop and my Linux is an Intel onboard video card, I''m not able to solve issues with CUDA and pytorch.
Anyway, this will be a good start to see how to use pytorch.
Let's start the install into default way on Scripts folder from my python version 3.6.4 folder installation.
C:\Python364\Scripts>pip3 install
Collecting torch==1.0.0 from
d64.whl (71.0MB)
    100% |████████████████████████████████| 71.0MB 100kB/s
Installing collected packages: torch
  Found existing installation: torch 0.4.1
    Uninstalling torch-0.4.1:
      Successfully uninstalled torch-0.4.1
Successfully installed torch-1.0.0

C:\Python364\Scripts>pip3 install torchvision
After I install the pytorch python module I import the pytorch and torchvision python modules.
First, as I expected the CUDA feature:
>>> import torch
>>> torch.cuda.is_available()
Let's make another test with pytorch:
>>> x = torch.rand(76, 79)
>>> x.size()
torch.Size([76, 79])
>>> print(x)
tensor([[0.1981, 0.3841, 0.9276,  ..., 0.3753, 0.7137, 0.7702],
        [0.8202, 0.9564, 0.5590,  ..., 0.0914, 0.4983, 0.7163],
        [0.0864, 0.4588, 0.0669,  ..., 0.3939, 0.0318, 0.8650],
        [0.9028, 0.8431, 0.8592,  ..., 0.3825, 0.2537, 0.7901],
        [0.2055, 0.3003, 0.8085,  ..., 0.0724, 0.9226, 0.9559],
        [0.3671, 0.1178, 0.3837,  ..., 0.7181, 0.5704, 0.9268]])
>>> torch.tensor([[1., -1.], [1., -1.]])
tensor([[ 1., -1.],
        [ 1., -1.]])
>>> torch.zeros([1, 4], dtype=torch.int32)
tensor([[0, 0, 0, 0]], dtype=torch.int32)
>>> torch.zeros([2, 4], dtype=torch.int32)
tensor([[0, 0, 0, 0],
        [0, 0, 0, 0]], dtype=torch.int32)
>>> torch.zeros([3, 4], dtype=torch.int32)
tensor([[0, 0, 0, 0],
        [0, 0, 0, 0],
        [0, 0, 0, 0]], dtype=torch.int32)
You can make many tests and check your instalation.
This is a screenshot with all features show by dir with pytorch and torchvision:

Friday, December 7, 2018

Python Qt5 - simple checkbox example.

Today we created a simple tutorial about QCheckBox and QLabel.
The purpose of this tutorial is to use QCheckBox in a GUI interface.
When we check QCheckBox, this will change the text from a QLabel.
The variables used by QCheckBox are my_checkbox and my_label for QLabel.
The result of my source code is this:

Let's see the source code:
# -*- coding: utf-8 -*-
@author: catafest
import sys
from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import QWidget, QCheckBox, QLabel, QApplication

class MyCheckBox(QWidget):
 def __init__(self):
  my_checkbox = QCheckBox("Check this , see result", self)

  self.my_label = QLabel("You can visit ", self)

  self.setWindowTitle(" PyQt5 ChecBox ")

 def change_my_option(self, state):
  if state  == Qt.Checked:
   self.my_label.setText("Thank's by")
   self.my_label.setText("You can visit")
if __name__ == '__main__':
 app = QApplication(sys.argv)
 win = MyCheckBox()

Wednesday, December 5, 2018

PySide2 and PyQt versions.

A short intro about this python module named PySide2 can be found on the Wikipedia webpage.
The purpose of this tutorial is to introduce concepts about licenses and develop python programs using ergonomic design interfaces with PySide2 and PyQt versions.

PySide2 is a Python binding of the cross-platform GUI toolkit Qt, currently developed by The Qt Company under the Qt for Python project. It is one of the alternatives to the standard library package Tkinter.
PySide was released under the LGPL in August 2009 by Nokia,[1] the former owners of the Qt toolkit, after Nokia failed to reach an agreement with PyQt developers Riverbank Computing[7] to change its licensing terms to include LGPL as an alternative license.

Now about the LGPL software license:

The GNU Lesser General Public License (LGPL) is a free software license published by the Free Software Foundation (FSF). The license allows developers and companies to use and integrate software released under the LGPL into their own (even proprietary) software without being required by the terms of a strong copyleft license to release the source code of their own components.

I wrote in the past about PySide and you can find on this blog or on my website.
Let's start installing Python using pip3.6.
C:\Python364>cd Scripts

C:\Python364\Scripts>pip3.6.exe install PySide2
Collecting PySide2
ne-win_amd64.whl (128.7MB)
    100% |████████████████████████████████| 128.7MB 44kB/s
Installing collected packages: PySide2
Successfully installed PySide2-5.11.2
The PySide2 python module is another way to connect Qt with Python modules.
You can take a look at this python module at Qt website .
The source code is more simple but this can put the development in trouble if you try to follow the PyQt way.
Let's see a simple example. I create the main window for this example.

The layout of this window named main_layout is split into two: secondary_splitter_1 and secondary_splitter_2.
Into this, I add for each area the defined class named SecondaryWindow.
The four variables for this SecondaryWindow class are named like secondary_window_1, secondary_window_2, secondary_window_3 and secondary_window_4.
Interface programming with PySide2 and PyQt keeps a classic form of statements and then structured implementations. It seems simpler to create interfaces with PySide, but the development and community interest seems to be attracted to PyQt.
In both cases, the programming speed in the python programming language is required.
Error management is simpler and more limited in PySide2. I have noticed PyQt essential changes in developing even more advanced versions (see PyQt4 and PyQt5).
Let's see the source code:
import sys
from PySide2 import QtGui, QtCore, QtWidgets
from PySide2.QtGui import *
from PySide2.QtCore import *
from PySide2.QtWidgets import *

class SecondaryWindow(QtWidgets.QWidget):

    def __init__(self, label, parent=None):
        super(SecondaryWindow, self).__init__(parent)

        self.label = QtWidgets.QLabel(label, parent=self)
        self.label.setStyleSheet("QLabel {font-size:18px;color:blue}")

        self.main_layout = QtWidgets.QVBoxLayout()

class MainWindow(QtWidgets.QWidget):

    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)

        self.secondary_window_1 = SecondaryWindow("1", parent=self)
        self.secondary_window_2 = SecondaryWindow("2", parent=self)
        self.secondary_window_3 = SecondaryWindow("3", parent=self)
        self.secondary_window_4 = SecondaryWindow("4", parent=self)

        self.secondary_splitter_1 = QtWidgets.QSplitter(QtCore.Qt.Horizontal, parent=self)

        self.secondary_splitter_2 = QtWidgets.QSplitter(QtCore.Qt.Horizontal, parent=self)

        self.main_splitter = QtWidgets.QSplitter(QtCore.Qt.Vertical, parent=self)

        self.main_layout = QtWidgets.QVBoxLayout()

        self.setWindowTitle("PySide2 example")
        self.resize(220, 220)

if __name__ == "__main__":
    app = QApplication(sys.argv)
    main_window = MainWindow()

Thursday, November 29, 2018

Python Qt5 - submenu example.

Using my old example I will create a submenu with PyQt5.
First, you need to know the submenu works like the menu.
Let's see the result:

The source code is very simple:
# -*- coding: utf-8 -*-
@author: catafest
import sys
from PyQt5.QtWidgets import QMainWindow, QAction, qApp, QApplication, QDesktopWidget, QMenu
from PyQt5.QtGui import QIcon

class Example(QMainWindow):
    #init the example class to draw the window application    
    def __init__(self):
    #create the def center to select the center of the screen         
    def center(self):
        # geometry of the main window
        qr = self.frameGeometry()
        # center point of screen
        cp = QDesktopWidget().availableGeometry().center()
        # move rectangle's center point to screen's center point
        # top left of rectangle becomes top left of window centering it
    #create the init UI to draw the application
    def initUI(self):               
        #create the action for the exit application with shortcut and icon
        #you can add new action for File menu and any actions you need
        exitAct = QAction(QIcon('exit.png'), '&Exit', self)        
        exitAct.setStatusTip('Exit application')
        #create the status bar for menu 
        #create the menu with the text File , add the exit action 
        #you can add many items on menu with actions for each item
        menubar = self.menuBar()
        fileMenu = menubar.addMenu('&File')
        # add submenu to menu 
        submenu = QMenu('Submenu',self)

        # some dummy actions
        submenu.addAction('Submenu 1')
        submenu.addAction('Submenu 2')
        # add to the top menu
        #resize the window application 
        self.resize(640, 480)
        #draw on center of the screen
        #add title on windows application 
        self.setWindowTitle('Simple menu')
        #show the application
        #close the UI class
if __name__ == '__main__':
    #create the application 
    app = QApplication(sys.argv)
    #use the UI with new  class
    ex = Example()
    #run the UI 

Monday, November 19, 2018

Using Google Classroom API with python.

Today I read and test Google API with the Python programming language.
You can find a good example here.
The example shows how to read with Google Classroom API, v1.
This example can be used as a default example if you want to use googlescopes.
The Google documentation tells us:
This document lists the OAuth 2.0 scopes that you might need to request to access Google APIs, depending on the level of access you need. Sensitive scopes require review by Google and have a sensitive indicator on the Google Cloud Platform (GCP) Console's OAuth consent screen configuration page. Many scopes overlap, so it's best to use a scope that isn't sensitive. For information about each method's scope requirements, see the individual API documentation.
The script use credentials.json file created by the Google project in the folder with the python script.
The script creates automatically when the authorization flow completes a token.json file.
The control of the project can be used with the Google Cloud Console.
The result of the example script can be seen in the next image:

Friday, November 16, 2018

Python Qt5 - setStyleSheet example.

Today I will show you how to style the PyQt5 widgets and create a good looking application interface.
The main goal of this tutorial is to see where you can use the style issue.
I used just one edit and one button to have a simple example.
The result of my example is this:

The example start with a simple application with QPushButton, QLineEdit.
Is more simple to use a class for the button because we need to create a different style for each action: enterEvent or leaveEvent and so on.
You can see I used QFont to change the font from button.
This class is named Push_button and will be used like any QPushButton from default PyQt5 examples.
We can do this for any widget and change it with setStyleSheet.
Another part of the code is for QLineEdit.
This can be changed easily with setStyleSheet, first with the default of this and make other changes when you need.
The source code has an QGridLayout to help us to align the widgets.
Let's see the source code:
from PyQt5 import QtWidgets, QtGui, QtCore
from PyQt5.QtCore import pyqtSignal

font_button = QtGui.QFont()

class Push_button(QtWidgets.QPushButton):
    def __init__(self, parent=None):
        super(Push_button, self).__init__(parent)
        self.setStyleSheet("margin: 1px; padding: 10px; \
      background-color: \
                           rgba(255,255,0,255); \
                           color: rgba(0,0,0,255); \
                           border-style: solid; \
                           border-radius: 4px; border-width: 3px; \
                           border-color: rgba(0,0,0,255);")

    def enterEvent(self, event):
        if self.isEnabled() is True:
            self.setStyleSheet("margin: 10px; padding: 10px; \
          background-color: \
                               rgba(255,255,0,255); \
                               color: rgba(0,0,10,255); \
                               border-style: solid; \
                               border-radius: 8px; \
                               border-width: 1px; \
                               border-color: \
        if self.isEnabled() is False:
            self.setStyleSheet("margin: 10px; padding: 10px; \
          background-color: \
                               rgba(255,255,0,255); \
                               color: rgba(0,0,10,255); \
                               border-style: solid; \
                               border-radius: 8px; \
                               border-width: 1px; \
                               border-color: \

    def leaveEvent(self, event):
        self.setStyleSheet("margin: 10px; padding: 10px; \
                           background-color: rgba(0,0,0,100); \
                           color: rgba(0,0,255,255); \
                           border-style: solid; \
                           border-radius: 8px; border-width: 1px; \
                           border-color: rgba(0,50,100,255);")

class QthreadApp(QtWidgets.QWidget):
    sig = pyqtSignal(str)
    def __init__(self, parent=None):
        QtWidgets.QWidget.__init__(self, parent)
        self.setWindowTitle("PyQt5 style application")
        self.setMinimumWidth(resolution.width() / 3)
        self.setMinimumHeight(resolution.height() / 2)
        self.setStyleSheet("QWidget { \
                           background-color: rgba(0,0,100,250);} \
                           QScrollBar:horizontal {width: 1px; \
                           height: 1px; \
                           background-color: rgba(0,100,255,0);} \
                           QScrollBar:vertical {width: 1px; \
                           height: 10px; \
                           background-color: rgba(0,41,59,255);}")
        self.linef = QtWidgets.QLineEdit(self)
        self.linef.setPlaceholderText("Input text ...")
        self.linef.setStyleSheet("margin: 10px; padding: 10px; \
                                 background-color: \
                                 color: rgba(255,0,0,255); \
                                 border-style: solid; \
                                 border-radius: 15px; \
                                 border-width: 1px; \
                                 border-color: \
        self.my_button = Push_button(self)
        self.my_grid = QtWidgets.QGridLayout()
        self.my_grid.addWidget(self.linef, 0, 0, 1, 220)
        self.my_grid.addWidget(self.my_button, 0, 220, 1, 1)
        self.my_grid.setContentsMargins(8, 8, 8, 8)

if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    desktop = QtWidgets.QApplication.desktop()
    resolution = desktop.availableGeometry()
    myapp = QthreadApp()
    myapp.move( - myapp.rect().center())
    desktop = QtWidgets.QApplication.desktop()
    resolution = desktop.availableGeometry()

Monday, November 12, 2018

Python Qt5 - QCalendarWidget example.

This tutorial is about QCalendarWidget.
Use a default application and add this widget.
You can change and get the date from the widget calendar like any widget.
The result of this source code is this result:

This is the source code for QCalendarWidget example:
import sys
from PyQt5 import *
from PyQt5.QtWidgets import QApplication, QCalendarWidget, QWidget, QLabel
from PyQt5.QtCore import *
from PyQt5.QtGui import *

class Example(QWidget):
   def __init__(self):
      super(Example, self).__init__()
   def initUI(self):
      my_calendar = QCalendarWidget(self)
      my_calendar.move(10, 20)
      self.my_label = QLabel(self)
      date = my_calendar.selectedDate()
      self.my_label.move(10, 220)
   def show_date(self, date):

def main():
   app = QApplication(sys.argv)
   ex = Example()
if __name__ == '__main__':

Saturday, November 10, 2018

Python Qt5 - QTabWidget example.

Today I test the QTabWidget with an simple example.
The source code uses the QTabWidget and create two Tab: FirstTab and TabTwo.
I add for each tab two labels: tab_one_label_one, tab_one_label_two,tab_two_label_one and tab_two_label_two.
For layouts, I used: vboxLayout with first_layout and second_layout.
The result of my running code is this:

The rest of the source code is simple:
import sys
from PyQt5.QtGui import QIcon
from PyQt5.QtWidgets import QDialog, QApplication, QWidget
from PyQt5.QtWidgets import QVBoxLayout, QTabWidget, QLabel

class TabDialog(QDialog):
    def __init__(self):

        self.setWindowTitle("Tab Widget Application")

        tabwidget = QTabWidget()
        tabwidget.addTab(FirstTab(), "First Tab")
        tabwidget.addTab(TabTwo(), "Second Tab")

        vboxLayout = QVBoxLayout()


class FirstTab(QWidget):
    def __init__(self):
        tab_one_label_one = QLabel("tab_one_label_one")
        tab_one_label_two = QLabel("tab_one_label_two")
        first_layout = QVBoxLayout()

class TabTwo(QWidget):
    def __init__(self):
        tab_two_label_one = QLabel("tab_two_label_one")
        tab_two_label_two = QLabel("tab_two_label_two")
        second_layout = QVBoxLayout()

if __name__ == "__main__":
    app = QApplication(sys.argv)
    tabdialog = TabDialog()

Friday, November 9, 2018

Python Qt5 - default icons with QStyle.

This is a simple example of QStyle.
Using the QStyle can solve more issues above this example.
The QStyle can solve more problems than this example.
You can change everything in PyQt5 and Qt.
The QStyle class is an abstract base class that encapsulates the look and feel of a GUI, read here.
This is the result of a source code I used to show you how can use default icons from PyQt5.

See this source code:
import sys
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *

class Widget(QWidget):
    def __init__(self, parent= None):
        super(Widget, self).__init__()
        icons = [
        Col_size = 6
        layout = QGridLayout()
        count = 0
        for i in icons:
            select_button = QPushButton(i)
            select_button.setIcon(, i)))
            layout.addWidget(select_button, count / Col_size, count % Col_size)
            count += 1
if __name__ == '__main__':
    app = QApplication(sys.argv)
    dialog = Widget()

Thursday, November 8, 2018

Python Qt5 - QFileDialog and QTextEdit example.

This tutorial is about QFileDialog and how to use it.
First you need to create a default PyQ5 application and add your method is called by my_OpenDialog.
This will be connected to one button.
My application uses the QTextEdit to show HTML and text files.
If you try to see another file this will open badly.
I set the completeSuffix just for HTML and text.
As you know this returns the complete suffix (extension) of the file.
The content of this file is put into QTextEdit widget create and named editor_text.
This is result of using QFileDialog with python:

This is the source code with the QFileDialog example:
import sys, os
from PyQt5 import QtCore, QtWidgets

class Window(QtWidgets.QWidget):
    def __init__(self):
        super(Window, self).__init__()
        self.setWindowTitle('Text document')
        self.editor_text = QtWidgets.QTextEdit(self)

        self.button_OpenDialog = QtWidgets.QPushButton('Open', self)

        layout = QtWidgets.QGridLayout(self)
        layout.addWidget(self.editor_text, 0, 0, 1, 1)
        layout.addWidget(self.button_OpenDialog, 1, 0)

    def my_OpenDialog(self):
        path = QtWidgets.QFileDialog.getOpenFileName(
            self, 'Open file', '',
            'HTML files (*.html);;Text files (*.txt)')[0]
        if path:
            file = QtCore.QFile(path)
                stream = QtCore.QTextStream(file)
                text = stream.readAll()
                info = QtCore.QFileInfo(path)
                if info.completeSuffix() == 'html':

if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)
    window = Window()
    window.resize(640, 480)

Wednesday, November 7, 2018

Python Qt5 - QLCDNumber and QDial example.

This tutorial uses a simple example of QLCDNumber and QDial.
The steps start with create the QWidget with the QLCDNumber and QDial.
You need to set geometry for both and connect the dial with valueChanged.
Finally you need to use show to see the QWidget.
The result is show into the next screenshot:

Let see the source code:
import sys
from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import (QWidget, QLCDNumber, QDial, QApplication)

class QLCDNumber_QDial(QWidget):
    def __init__(self):

    def initUi(self):
        the_lcd = QLCDNumber(self)
        the_dial = QDial(self)

        self.setGeometry(150, 100, 220, 100)



if __name__ == '__main__':
    app = QApplication(sys.argv)
    run = QLCDNumber_QDial() 

Tuesday, November 6, 2018

Python Qt5 - QColorDialog example.

Today I will show you how to use the QColorDialog and clipboard with PyQt5.
You can read documentation from the official website.
This example used a tray icon with actions for each type of code color.
The code of color is put into clipboard area and print on the shell.
I use two ways to get the code of color:
  • parse the result of currentColor depends by type of color codel;
  • get the code of color by a special function from QColorDialog;
To select the color I want to use is need to use the QColorDialog:

Let's see the source code:
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *

# create the application
app = QApplication([])

# get the icon file
icon = QIcon("icon.png")

# create clipboard
clipboard = QApplication.clipboard()
# create dialog color
dialog = QColorDialog()

# create functions to get parsing color
def get_color_hex():
    if dialog.exec_():
        color = dialog.currentColor()

def get_color_rgb():
    if dialog.exec_():
        color = dialog.currentColor()
        clipboard.setText("rgb(%d, %d, %d)" % (

def get_color_hsv():
    if dialog.exec_():
        color = dialog.currentColor()
        clipboard.setText("hsv(%d, %d, %d)" % (
            color.hue(), color.saturation(), color.value()
# create function to use getCmyk 
def get_color_getCmyk():
    if dialog.exec_():
        color = dialog.currentColor()
        clipboard.setText("Cmyk(%d, %d, %d, %d, %d)" % (

# create the tray icon application
tray = QSystemTrayIcon()

# create the menu and add actions
menu = QMenu()
action1 = QAction("Hex")

action2 = QAction("RGB")

action3 = QAction("HSV")

action4 = QAction("Cmyk")

action5 =QAction("Exit")

# add the menu to the tray icon application


Monday, November 5, 2018

Python Qt5 - tray icon example.

This tutorial is about another tray icon application type.
The base application is the same like any application with some changes with this steps:
- QSystemTrayIcon this will start to create the application like an tray icon application;
- create one menu to show if you use the right click of mouse;
- add a menu with action items;
- add the exit action to close the tray icon application;
- you can use the action item from menu to print a message
Let's see the source code:
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
# create the application
app = QApplication([])

# create the icon
icon = QIcon("icon.png")

# create the tray icon 
tray = QSystemTrayIcon()

# this will print a message 
def print_msg():
 print("This action is triggered connect!")

# create the menu for tray icon
menu = QMenu()

# add one item to menu 
action = QAction("This is menu item")

# add exit item to menu 
exitAction = QAction("&Exit")

# add the menu to the tray

# start application execution 
This is result of the running source code:

Sunday, November 4, 2018

Python Qt5 - QtSql with QtOpenGL example.

Today I will show you how to deal with QtOpenGL.
Let's make a test to see what is this:
>>> import PyQt5
>>> from PyQt5.QtOpenGL import *
>>> dir(PyQt5.QtOpenGL)
['QGL', 'QGLContext', 'QGLFormat', 'QGLWidget', '__doc__', '__file__', '__loader
__', '__name__', '__package__', '__spec__']
The QtOpenGL is used to take an OpenGL content and show into the PyQt5 application.
You need to kknow how to use OpenGL API.
You can see the result of this example:

This is the source code for my example:
import sys
import math

from PyQt5.QtCore import Qt
from PyQt5.QtGui import QColor
from PyQt5.QtWidgets import QApplication, QMessageBox
from PyQt5.QtOpenGL import QGL, QGLFormat, QGLWidget

    from OpenGL import GL
except ImportError:
    app = QApplication(sys.argv)
    QMessageBox.critical(None, "OpenGL samplebuffers",
            "PyOpenGL must be installed to run this example.")

# use to create OpenGL content 
class GLWidget(QGLWidget):
    # rotation to 0
    rot = 0.0

    def __init__(self, parent):
        super(GLWidget, self).__init__(QGLFormat(QGL.SampleBuffers), parent)
        self.list_ = []
        self.setWindowTitle("OpenGL with sample buffers")

    def initializeGL(self):
        GL.glOrtho( -.5, .5, .5, -.5, -1000, 1000)
        GL.glClearColor(1.0, 1.0, 1.0, 1.0)


    def resizeGL(self, w, h):
        GL.glViewport(0, 0, w, h)

    def paintGL(self):

        GL.glTranslatef( -0.25, -0.10, 0.0)
        GL.glScalef(0.75, 1.15, 0.0)
        GL.glRotatef(GLWidget.rot, 0.0, 0.0, 1.0)

        GL.glTranslatef(0.25, -0.10, 0.0)
        GL.glScalef(0.75, 1.15, 0.0)
        GL.glRotatef(GLWidget.rot, 0.0, 0.0, 1.0)

        GLWidget.rot += 0.2

        self.renderText(-0.35, 0.4, 0.0, "Multisampling enabled")
        self.renderText(0.15, 0.4, 0.0, "Multisampling disabled")

    def timerEvent(self, event):
    # create one object 
    def makeObject(self):
        x1 = +0.05
        y1 = +0.25
        x2 = +0.15
        y2 = +0.21
        x3 = -0.25
        y3 = +0.2
        x4 = -0.1  
        y4 = +0.2
        x5 = +0.25 
        y5 = -0.05

        self.list_ = GL.glGenLists(1)
        GL.glNewList(self.list_, GL.GL_COMPILE)
        self.geometry(GL.GL_POLYGON, x1, y1, x2, y2, x3, y3, x4, y4, x5, y5)
    # create geometry of object depend of render - GL_POLYGON
    # used five points 
    def geometry(self, primitive, x1, y1, x2, y2, x3, y3, x4, y4, x5, y5):

        GL.glVertex2d(x1, y1)
        GL.glVertex2d(x2, y2)
        GL.glVertex2d(x3, y3)
        GL.glVertex2d(x4, y4)
        GL.glVertex2d(x5, y5)

# start the application 
if __name__ == '__main__':

    app = QApplication(sys.argv)

    my_format = QGLFormat.defaultFormat()

    if not QGLFormat.hasOpenGL():
        QMessageBox.information(None, "OpenGL using samplebuffers",
                "This system does not support OpenGL.")

    widget = GLWidget(None)

    if not widget.format().sampleBuffers():
        QMessageBox.information(None, "OpenGL using samplebuffers",
                "This system does not have sample buffer support.")

    widget.resize(640, 480)


Saturday, November 3, 2018

Python Qt5 - QtSql with QSQLITE example.

Today I will show you how to deal with QtSql and QSQLITE and show a table into an MDI (Multiple Document Interface) application.
First I create tree scripts named:
  • - create a memory database and add value into table;
  • - create a model for the table;
  • - show the MDI application with the model table database;
The source code is commented and is simple to understand.
Let's see this python scripts:
First is
from PyQt5 import QtWidgets, QtSql
from PyQt5.QtSql import *

def createConnection():
    db = QtSql.QSqlDatabase.addDatabase("QSQLITE")
    if not
        QtWidgets.QMessageBox.critical(None, "Cannot open memory database",
                             "Unable to establish a database connection.\n\n"
                             "Click Cancel to exit.", QtWidgets.QMessageBox.Cancel)
        return False
    query = QtSql.QSqlQuery()
    #print (os.listdir("."))
    query.exec("DROP TABLE IF EXISTS Websites")
    query.exec("CREATE TABLE Websites (ID INTEGER PRIMARY KEY NOT NULL, " +     "website VARCHAR(20))")
    query.exec("INSERT INTO Websites (website) VALUES('')")
    query.exec("INSERT INTO Websites (website) VALUES('')")
    query.exec("INSERT INTO Websites (website) VALUES('')")
    query.exec("INSERT INTO Websites (website) VALUES('')")
    query.exec("INSERT INTO Websites (website) VALUES('')")
    return True
The next is the python script with the model of the table from database:
from PyQt5 import QtWidgets, QtSql

from PyQt5 import QtWidgets, QtSql

class WebsitesWidget(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(WebsitesWidget, self).__init__(parent)
 # this layout_box can be used if you need more widgets 
 # I used just one named WebsitesWidget
        layout_box = QtWidgets.QVBoxLayout(self)
        my_view = QtWidgets.QTableView()
 # put viwe in layout_box area
 # create a table model
        my_model = QtSql.QSqlTableModel(self)
 #show the view with model  
The last python script named will create the MDI application and will show databese table:
from PyQt5 import QtWidgets, QtSql
from PyQt5_connection import createConnection
# this will import any classes from PyQt5_view script
from PyQt5_view import WebsitesWidget

class MainWindow(QtWidgets.QMainWindow):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)

        self.MDI = QtWidgets.QMdiArea()

        SubWindow1 = QtWidgets.QMdiSubWindow()
 # you can add more widgest 
        #SubWindow2 = QtWidgets.QMdiSubWindow()

if __name__ == '__main__':
    import sys

    app = QtWidgets.QApplication(sys.argv)

    if not createConnection():
        print("not connect")
    w = MainWindow()
This is the result of the running python script:

Thursday, November 1, 2018

Python Qt5 - QtWebEngine example.

The QtWebEngine is the new web rendering engine that is planned to replace QtWebKit in Qt.
The official website tells us:
QtWebEngineWidgets or QtWebEngine libraries, depending on application type
Let's test this web rendering engine with a simple source code:
import sys
from PyQt5.QtCore import *
from PyQt5.QtWidgets import QApplication
# use the QtWebEngineWidgets
from PyQt5.QtWebEngineWidgets import *
# start my_app
my_app = QApplication(sys.argv)
# open webpage
my_web = QWebEngineView()
# sys exit function
The output of this running source code.

Friday, October 26, 2018

Python Qt5 - MP3 player example.

This tutorial with PyQt5 will allow us to play an MP3 file using QtMultimedia.
I used a test.mp3 file in the same folder with my python script.
This is the source script:
import sys

from PyQt5 import QtCore, QtWidgets, QtMultimedia

if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)
    filename = 'test.mp3'
    fullpath = QtCore.QDir.current().absoluteFilePath(filename) 
    media = QtCore.QUrl.fromLocalFile(fullpath)
    content = QtMultimedia.QMediaContent(media)
    player = QtMultimedia.QMediaPlayer()

Wednesday, October 24, 2018

Python Qt5 - webcam example.

Today I come with another source code.
This example uses QtMultimedia to create use of the webcam.
The source code follows the steps from finding, set and use a webcam.
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
from PyQt5.QtMultimedia import *
from PyQt5.QtMultimediaWidgets import *

import os
import sys

class MainWindow(QMainWindow):

    def __init__(self, *args, **kwargs):
        super(MainWindow, self).__init__(*args, **kwargs)

        self.online_webcams = QCameraInfo.availableCameras()
        if not self.online_webcams:
            pass #quit
        self.exist = QCameraViewfinder()

        # set the default webcam.

    def get_webcam(self, i):
        self.my_webcam = QCamera(self.online_webcams[i])
        self.my_webcam.error.connect(lambda: self.alert(self.my_webcam.errorString()))

    def alert(self, s):
        This handle errors and displaying alerts.
        err = QErrorMessage(self)

if __name__ == '__main__':

    app = QApplication(sys.argv)

    window = MainWindow()

Tuesday, October 23, 2018

Python Qt5 - toolbar example.

This is a simple example with PyQt5 python module and python 3.6.4 version.
The example is about how to create a toolbar with PyQt5.
The base of this source code is the create a default window application.
I create a toolbar and I add an action to this toolbar.
The name of the toolbar is my_toolbar.
The action is named one_action.
This action is linked to a python function named action_one.
I add to my source code another function named alert.
This is good for debugging part to handle with errors and displaying alerts.
Let's see the source code:
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
import sys

class MainWindow(QMainWindow):

    def __init__(self, *args, **kwargs):
        super(MainWindow, self).__init__(*args, **kwargs)
        self.status = QStatusBar()
        my_toolbar = QToolBar("toolbar")
        my_toolbar.setIconSize(QSize(48, 48))
        one_action = QAction(QIcon(), "Action one", self)        
        one_action.setStatusTip("Action one on toolbar")
        self.setWindowTitle("Window PyQt5 - 001")

    def action_one(self):
        print("Action one")

    def alert(self, s):
        This handle errors and displaying alerts.
        err = QErrorMessage(self)

if __name__ == '__main__':

    app = QApplication(sys.argv)
    app.setApplicationName("Window PyQt5 - 001")

    window = MainWindow()

Sunday, October 21, 2018

The pandas python module.

The official documentation of this python module tells us:
pandas is a Python package providing fast, flexible, and expressive data structures designed to make working with “relational” or “labeled” data both easy and intuitive. It aims to be the fundamental high-level building block for doing practical, real-world data analysis in Python. Additionally, it has the broader goal of becoming the most powerful and flexible open source data analysis/manipulation tool available in any language. It is already well on its way toward this goal.
C:\Python27>cd Scripts

C:\Python27\Scripts>pip install pandas
Collecting pandas
  Downloading pandas-0.20.3-cp27-cp27m-win32.whl (7.6MB)
    100% |################################| 7.6MB 153kB/s
Requirement already satisfied: python-dateutil in c:\python27\lib\site-packages (from pandas)
Requirement already satisfied: numpy>=1.7.0 in c:\python27\lib\site-packages (from pandas)
Requirement already satisfied: pytz>=2011k in c:\python27\lib\site-packages (from pandas)
Requirement already satisfied: six>=1.5 in c:\python27\lib\site-packages (from python-dateutil->pandas)
Installing collected packages: pandas
Successfully installed pandas-0.20.3

OpenGL and OpenCV with python 2.7 - part 006.

Today I deal with a simple example about how to use your webcam like a python module.
This will allow you to make your python module for your webcam.
My reason was to make a good webcam module to work with python modules like OpenCV and OpenGL and webcam devices.
The source code is simple and has just three functions: start, _update_frame and get_current_frame.
You can make more functions into this python module named webcam.
import cv2
from threading import Thread
class webcam:
    def __init__(self):
        self.video_capture = cv2.VideoCapture(0)
        self.current_frame =[1]
    # create thread for capturing images
    def start(self):
        Thread(target=self._update_frame, args=()).start()
    def _update_frame(self):
            self.current_frame =[1]
    # get the current frame
    def get_current_frame(self):
        return self.current_frame
I make also a python script to test this python module:
from webcam import webcam
import cv2
cam = webcam()
while True:
    # get image from webcam
    image = cam.get_current_frame()

The shutil python module.

The shutil module helps you to accomplish tasks, such as: copying, moving, or removing directory trees.
This python script creates a zip file in the current directory containing all contents of dir and then clears dir.

import shutil
from os import makedirs

def zip(out_fileName, dir):
shutil.make_archive(str(out_fileName), 'zip', dir)

The scapy python module - part 002.

This is another python tutorial about scapy python module.
The last was made on Linux and now I used Windows 10 OS.
Let's install this python module with python version 2.7.13 and pip.
C:\>cd Python27

C:\Python27>cd Scripts

C:\Python27\Scripts>pip install scapy
Collecting scapy
  Downloading scapy-2.3.3.tgz (1.4MB)
    100% |################################| 1.4MB 736kB/s
  In the tar file c:\users\mythcat\appdata\local\temp\pip-26vi9x-unpack\scapy-2.3.3.tgz 
the member scapy-2.3.3/README is invalid: unable to resolve link inside archive
Installing collected packages: scapy
  Running install for scapy ... done
Successfully installed scapy-2.3.3
The next step is to deal with
Python 2.7.13 (v2.7.13:a06454b1afa1, Dec 17 2016, 20:42:59) [MSC v.1500 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import scapy
>>> from scapy import *
>>> dir(scapy)
['VERSION', '_SCAPY_PKG_DIR', '__builtins__', '__doc__', '__file__', '__name__', '__package__',
 '__path__', '_version', '_version_from_git_describe', 'base_classes', 'config', 'dadict', 'data',
 'error', 'os', 'plist', 'pton_ntop', 're', 'subprocess', 'supersocket', 'themes', 'utils', 

This is not working on WINDOWS

Using PyUSB with python 3.x .

C:\Python34\Scripts>pip3.4.exe install PyUSB
Downloading/unpacking PyUSB
  Running (path:C:\Users\mythcat\AppData\Local\Temp\pip_build_mythcat\PyUSB\ egg_info for package PyUSB

Installing collected packages: PyUSB
  Running install for PyUSB

Successfully installed PyUSB
Cleaning up...
Now you need to install this filter from here.
If not, you can get errors like this: raise NoBackendError('No backend available')
usb.core.NoBackendError: No backend available
Let's make a simple test example:
import usb.core
import usb.util
import sys

class find_class(object):
    def __init__(self, class_):
        self._class = class_
    def __call__(self, device):
        # first, let's check the device
        if device.bDeviceClass == self._class:
            return True
        # ok, transverse all devices to find an
        # interface that matches our class
        for cfg in device:
            # find_descriptor: what's it?
            intf = usb.util.find_descriptor(
            if intf is not None:
                return True

        return False

all = usb.core.find(find_all=1, custom_match=find_class(7))
print (all)
And show the result:
< generator 0x0000000003d8d5e8="" at="" device_iter="" object="" >

The ansible python module - part 001.

Ansible is an IT automation tool.
It can configure systems, deploy software, and orchestrate more advanced IT tasks such as continuous deployments or zero downtime rolling updates.
First, you need to install the VCForPython27.
Install now the pycrypto python module:
C:\Python27\Scripts>pip install  --upgrade  --trusted-host pycrypto
Collecting pycrypto
  Downloading pycrypto-2.6.1.tar.gz (446kB)
    100% |################################| 450kB 3.8MB/s
Installing collected packages: pycrypto
  Running install for pycrypto ... done
Successfully installed pycrypto-2.6.1

C:\Python27\Scripts>pip install --trusted-host ansible
Collecting ansible
Downloading ansible- (4.3MB)
100% |################################| 4.3MB 365kB/s
Requirement already satisfied: jinja2 in c:\python27\lib\site-packages (from ansible)
Collecting PyYAML (from ansible)
Installing collected packages: ansible
  Running install for ansible ... done
Successfully installed ansible-

Programmer's Notepad - free editor with PyPN python module.

Programmer's Notepad is a free, open source, text editor with special features for coders.
This editor comes with a variety of text clips representing common programming languages.
I saw 43 of text clips to start your programming.
Syntax highlighting
Text Clips for simple text insertion
Code folding / outlining
Flexible Regular Expression support
Code navigation using Ctags
Projects for navigating large code bases
Extend using Python or C++
For example, if you start with the HTML then every tag will autocomplete with the end tag.
You can install the PyPN python module and used with this editor:
C:\Python364\Scripts>pip install PyPN
Collecting PyPN
Installing collected packages: PyPN
Successfully installed PyPN-0.9
More about PyPN module can be found here.
You can donate to support the project.

Friday, September 28, 2018

Python 2.7 : Python geocoding without key.

Today I will come with a simple example about geocoding.
I used JSON and requests python modules and python version 2.7.
About geocoding I use this service provide by datasciencetoolkit.
You can use this service free and you don't need to register to get a key.
Let's see the python script:
import requests
import json

url = u''
par = {
    u'sensor': False,
    u'address': u'London'

my = requests.get(
json_out = json.loads(my.text)

if json_out['status'] == 'OK':
    print([r['geometry']['location'] for r in json_out['results']])
I run this script and I test with google map to see if this works well.
This is output and working well with the geocoding service:

Friday, September 7, 2018

Windows - test Django version 2.1.1 .

I used python version 3.6.4 to test the last Django framework version.
Add your python to the path environment variable under Windows O.S.
Create your working folder:
C:\Python364>mkdir mywebsite
Go to the folder to install all you need:
C:\Python364>cd mywebsite
Use a virtual environment using the virtualenv command:
C:\Python364\mywebsite>python -m venv myvenv
(myvenv) C:\Python364\mywebsite>python -m pip install --upgrade pip
(myvenv) C:\Python364\mywebsite>pip3.6 install django
Collecting django
If you try to run again this command you will see the version of Django:
(myvenv) C:\Python364\mywebsite>pip3.6 install django
Requirement already satisfied: django in c:\python364\mywebsite\myvenv\lib\
site-packages (2.1.1)
Requirement already satisfied: pytz in c:\python364\mywebsite\myvenv\lib\
site-packages (from django) (2018.5)
You need to run the django-admin command:
(myvenv) C:\Python364\mywebsite>cd myvenv
(myvenv) C:\Python364\mywebsite\myvenv>cd Scripts
(myvenv) C:\Python364\mywebsite\myvenv\Scripts>django-admin.exe startproject mysite
(myvenv) C:\Python364\mywebsite\myvenv\Scripts>dir my*
(myvenv) C:\Python364\mywebsite\myvenv\Scripts>cd mysite
(myvenv) C:\Python364\mywebsite\myvenv\Scripts\mysite&
Make change to settings file:
(myvenv) C:\Python364\mywebsite\myvenv\Scripts\mysite>cd mysite
(myvenv) C:\Python364\mywebsite\myvenv\Scripts\mysite\mysite>notepad
Change UTC timezone:
TIME_ZONE = 'Europe/Paris'
Change host:
The next step is to use this commands:
(myvenv) C:\Python364\mywebsite\myvenv\Scripts\mysite\mysite>cd ..
(myvenv) C:\Python364\mywebsite\myvenv\Scripts\mysite>python migrate
Operations to perform:
  Apply all migrations: admin, auth, contenttypes, sessions
Running migrations:
  Applying contenttypes.0001_initial... OK
  Applying auth.0001_initial... OK
  Applying admin.0001_initial... OK
  Applying admin.0002_logentry_remove_auto_add... OK
  Applying admin.0003_logentry_add_action_flag_choices... OK
  Applying contenttypes.0002_remove_content_type_name... OK
  Applying auth.0002_alter_permission_name_max_length... OK
  Applying auth.0003_alter_user_email_max_length... OK
  Applying auth.0004_alter_user_username_opts... OK
  Applying auth.0005_alter_user_last_login_null... OK
  Applying auth.0006_require_contenttypes_0002... OK
  Applying auth.0007_alter_validators_add_error_messages... OK
  Applying auth.0008_alter_user_username_max_length... OK
  Applying auth.0009_alter_user_last_name_max_length... OK
  Applying sessions.0001_initial... OK
Let's try this steps with the browser:
(myvenv) C:\Python364\mywebsite\myvenv\Scripts\mysite>python runserver
Performing system checks...

System check identified no issues (0 silenced).
September 07, 2018 - 16:30:13
Django version 2.1.1, using settings 'mysite.settings'
Starting development server at
Quit the server with CTRL-BREAK.
[07/Sep/2018 16:30:16] "GET / HTTP/1.1" 200 16348
[07/Sep/2018 16:30:21] "GET / HTTP/1.1" 200 16348
This is the result:

Let's start Django application named myblog and add to :
(myvenv) C:\Python364\mywebsite\myvenv\Scripts\mysite>python startapp

(myvenv) C:\Python364\mywebsite\myvenv\Scripts\mysite>dir
(myvenv) C:\Python364\mywebsite\myvenv\Scripts\mysite>cd mysite
(myvenv) C:\Python364\mywebsite\myvenv\Scripts\mysite\mysite>notepad
Search into this line and add 'myblog', , see:
# Application definition

Let's change from myblog folder:
(myvenv) C:\Python364\mywebsite\myvenv\Scripts\mysite\mysite>cd ..
(myvenv) C:\Python364\mywebsite\myvenv\Scripts\mysite>cd myblog
(myvenv) C:\Python364\mywebsite\myvenv\Scripts\mysite\myblog>notepad
Add this source code:
from django.db import models
# Create your models here.
from django.utils import timezone
from django.contrib.auth.models import User

class Post(models.Model):
 author = models.ForeignKey(User,on_delete=models.PROTECT)
 title = models.CharField(max_length=200)
 text = models.TextField()
 create_date = models.DateTimeField(
 published_date = models.DateTimeField(blank=True, null=True)
 def publish(self):
  self.publish_date =
 def __str__(self):
  return self.title
Go and run this commands for model Post with makemigrations myblog and migrate
myblog :
(myvenv) C:\Python364\mywebsite\myvenv\Scripts\mysite\myblog>cd ..
(myvenv) C:\Python364\mywebsite\myvenv\Scripts\mysite>python 
makemigrations myblog
Migrations for 'myblog':
    - Create model Post
(myvenv) C:\Python364\mywebsite\myvenv\Scripts\mysite>python migrate 
Operations to perform:
  Apply all migrations: myblog
Running migrations:
  Applying myblog.0001_initial... OK
Add this source code to from myblog folder:
(myvenv) C:\Python364\mywebsite\myvenv\Scripts\mysite>cd myblog
(myvenv) C:\Python364\mywebsite\myvenv\Scripts\mysite\myblog>notepad
Let's test again:
(myvenv) C:\Python364\mywebsite\myvenv\Scripts\mysite\myblog>cd ..
(myvenv) C:\Python364\mywebsite\myvenv\Scripts\mysite>python runserver
Performing system checks...

System check identified no issues (0 silenced).
September 07, 2018 - 17:19:00
Django version 2.1.1, using settings 'mysite.settings'
Starting development server at
Quit the server with CTRL-BREAK.
Check the admin interface with add admin word to link, see:

If you see some errors this will be fixed later.
Let's make a superuser with this command:
(myvenv) C:\Python364\mywebsite\myvenv\Scripts\mysite>python 
Username (leave blank to use 'catafest'): catafest
Email address:
Password (again):
This password is too short. It must contain at least 8 characters.
Bypass password validation and create user anyway? [y/N]: y
Superuser created successfully.
Run again this command and log in with your user and password:
(myvenv) C:\Python364\mywebsite\myvenv\Scripts\mysite>python runserver
This is the result with users and posts.

Click on Add button to add your post.
The result is this:

I don't make settings for URL and view. This will be changed by users.