Mathesis Wiki

from __future__ import division
# import numpy as np
import math
 
 
def activeFunc(value):
    '''Setzt den Wert in die Sigmoid-Funktion ein.'''
    # print "input:", value
    return 1/(1+math.e**(-value))
 
 
def derivedActFunc(value):
    return (math.e**-value)/(1+math.e**-value)**2
 
 
class Neuron():
    def __init__(self, weights):
        self.weights = weights
        self.additionalInput = 0
        self.inputs = 0
        self.value = 0
        self.isActive = False
        # print "Weights:", self.weights, "(" + str(len(self.weights)) + ")"
 
    def processInput(self, inputs):
        '''Verarbeitet den Input, indem es jeden Wert mit seinem Gewicht
            multipliziert und das Ergebnis in die Sigmoid-Funktion einsetzt.'''
        value = self.additionalInput
        self.inputs = inputs
        for i in range(len(inputs)):
            value += self.weights[i]*inputs[i]
        self.value = value
        self.output = activeFunc(value)
        self.isActive = self.output >= 0.5
 
    def setWeights(self, weights):
        self.weights = weights
 
    def printNeuron(self):
        return 'N:' + str(len(self.weights)), self.weights

# -*-coding:utf8-*-
from __future__ import division
import neuron as nr
import random
import math
import readfile as rf
 
 
def sProduct(list1, list2, prit=False):
    '''Berechnet das SkalarProdukt zweier Vektoren'''
    value = 0
    for i in range(len(list1)):
        if prit:
            print list1[i]
            print list2[i]
        value += list1[i]*list2[i]
    return value
 
 
class Network():
    def __init__(self, neuronNum):
        '''Generiert ein neues Netzwerk jeweils neuronNum verschiedenen
            Neuronen in layers Layern und inputNum Gewichten pro Neuron.'''
        self.layers = []
        # Neues Layer anlegen
        for layer in range(len(neuronNum)-1):
            # So viele Neuronen anlegen, wie das Layer Outputs hat
            neurons = []
            for i in range(neuronNum[layer+1]):
                weights = []
                # Fuer jedes Neuron so viele Gewichte anlegen,
                # wie das Layer Inputs hat
                for j in range(neuronNum[layer]):
                    weights.append(random.uniform(-0.03, 0.03))
                neurons.append(nr.Neuron(weights))
            self.layers.append(neurons)
        self.learningRate = 0.015
        self.softmax = 1
        self.decay = 0.05
        # for layer in range(len(self.layers)):
        #     print "Layer:", layer, [neuron.printNeuron()
        #                             for neuron in self.layers[layer]]
 
    def getOutput(self, inputs):
        '''Testet das Netzwerk auf einen Input-Vektor und den korrekten
            Output'''
        end_output = []
        for layer in self.layers:
            output = []
            for nrn in layer:
                nrn.processInput(inputs)
                output.append(nrn.output)
                end_output.append(nrn.value)
            inputs = output[:]
        # self.softmax = sum([math.e**value for value in end_output])
        return inputs
 
    def compareOutputs(self, output, expOutput):
        '''Berechnet den quadratischen Fehler zwischen erwartetem und
        tatsaechlichem Output'''
        error = 0
        for i in range(output):
            error += (output[i]-expOutput[i])**2
        return 0.5*error
 
    def update(self, inputs, expOutput):
        output = self.getOutput(inputs)
        newWeightsList = []
        deltas = []
        # zunächst werden die Deltas berechnet
        for i in range(len(self.layers[-1])):
            deltas.append((output[i] - expOutput[i]) *
                          nr.derivedActFunc(self.layers[-1][i].value))
        for layer in range(len(self.layers)):
            # print "Layer", len(self.layers)-layer-1, "of", len(self.layers)
            newWeights = []
            for n in range(len(self.layers[-(layer+1)])):
                # print "Neuron", n, "of", len(self.layers[-layer-1])
                newNeuronWeights = []
                for w in range(len(self.layers[-(layer+1)][n].weights)):
                    weight = self.layers[-(layer+1)][n].weights[w]
                    newNeuronWeights.append(weight*(1-self.decay) - self.learningRate *
                                            deltas[n]*self.layers[-(layer+1)][n].inputs[w])
                newWeights.append(newNeuronWeights)
            newWeightsList.append(newWeights)
            # deltas update
            newdeltas = []
            for l in range(len(self.layers[-(layer+1)][0].weights)):
                value = 0
                # print -(layer+2)
                if -(layer+1) == -len(self.layers):
                    value = inputs[l]
                else:
                    value = self.layers[-(layer+2)][l].value
                newdeltas.append(sum([deltas[k]*self.layers[-(layer+1)][k].weights[l] for k in range(len(deltas))])*nr.derivedActFunc(value))
            deltas = newdeltas
        for layer in range(len(self.layers)):
            for n in range(len(self.layers[layer])):
                self.layers[layer][n].setWeights(newWeightsList[-layer-1][n])
 
    def updateDataset(self, dataset):
        '''Trainiert das Neuronale Netz anhand einer Liste von Inputs und
        erwarteten Outputs'''
        for data in range(len(dataset)):
            # print data+1, "/", len(dataset)
            self.update(dataset[data][0], dataset[data][1])
 
    def testDataset(self, dataset):
        correctAnswers = 0
        for data in dataset:
            res = self.getOutput(data[0])
            # print res
            # print res, data[1]
            maxvalue = 0
            for i in range(len(res)):
                if (res[i] > res[maxvalue]):
                    maxvalue = i
            if (data[1][maxvalue] == 1):
                correctAnswers += 1
                print "   " * maxvalue, maxvalue
            #     print maxvalue, [round(num, 5) for num in res]
            # else:
            #     print data[1], [round(num, 5) for num in res]
        print correctAnswers / len(dataset)
        return correctAnswers / len(dataset)
 
if __name__ == "__main__":
    n = Network([256, 12, 10])
    traindata = rf.readFile("zip.train")
    testdata = rf.readFile("zip.test")
 
    value = n.testDataset(testdata)
    n.updateDataset(traindata)
    newvalue = n.testDataset(testdata)
    while newvalue - value > 10**-4:
        value = newvalue
        n.updateDataset(traindata)
        newvalue = n.testDataset(testdata)

import numpy as np
import matplotlib.pyplot as plt
 
 
def readFile(filename, skip=257):
    file = open(filename, 'r')
    all = file.read()
    numbers = [float(num) for num in all.split()]
    data = []
    for i in range(len(numbers)//skip):
        number = numbers[i*skip:(i+1)*skip]
        # print number
        im = [1+num for num in number][1:]
        data.append((im, [0]*int(number[0])+[1]+[0]*(9-int(number[0]))))
    return data
 
 
def convertToMatrix(data, x=16, y=16):
    arr = np.reshape(np.array(data), (x, y))
    return arr
 
 
def showData(data):
    for dat in data:
        print (dat[1])
        plt.imshow(convertToMatrix(dat[0]), cmap="Greys")
        plt.show()