how to write a neural network code for classification problem from scratch

I need to train a neural network for classification and I want to code from scratch because I want to have control over it. I tried using nprtool but I am not satisfied with the output and the only thing I was able to change was the hidden neuron . Please,can someone provide me with a link,video link or books that I can go through to get the required knowledge? Also,any source code with real life problem is welcomed,just for me to see how the code should look like and how it works. Thanks

[Sivakumaran Chandrasekaran]

you can more details about neural network from the demos present inside MATLAB software

Answer 1

[Greg Heath]

Using the command line:

 help patternnet
 doc patternnet

Search in the NEWSGROUP and ANSWERS

 greg patternnet

Hope this helps. Thank you for formally accepting my answer Greg

Answer 2

[Thili Mahanama]

This is the code of neural networks for binary classification problem from scratch.and when the number of features(inputs) and target class elevates, the calculations that has to done increases largely,So the error rates. Try with classification learner in matlab app ( after 2015a) or go with neural networks tool box for good accuracies.

 clc
clear all;
x1=[0,1,0,1]
x2=[0,0,1,1]
ylabel=[0,1,1,0]

w13=0.5; w14=0.9; w23=0.4; w24=1; w35=-0.12; w45=1.1; w03=0.8; w04=-0.1; w05=0.3;

for ii=1:4

   if ylabel(ii)==0
    scatter(x1(ii) ,x2(ii),'o','r')
    hold on

   else
        scatter(x1(ii) ,x2(ii),'*','r')
hold on   
end
end

 alpha=0.1;
  i=1;  

    for u=1:4
                while i<=1000
    L3=w23*x2(1,u)+w13*x1(1,u)-w03;
    y3=sigmf(L3,[1 0])
    L4=w24*x2(1,u)+w14*x1(1,u)-w04;
    y4=sigmf(L4,[1 0])
    L5=w23*x2(1,u)+w13*x1(1,u)-w03;
    y5=sigmf(L5,[1 0])

    e=ylabel(1,u)-y5;
    d5=y5.*(1-y5).*e
    d3=y3.*(1-y3).*d5*w35;
    d4=y4.*(1-y4).*d5*w45;

    dw35=d5*alpha.*y3;
    dw45=d5*alpha.*y4;
    dw05=d5*alpha.*(-1);
    dw03=d3*alpha.*(-1);
    dw13=d3*alpha.*x1(1,u);
    dw23=d3*alpha.*x2(1,u);
    dw04=d4*alpha.*(-1);
    dw14=d4*alpha.*x1(1,u);
    dw24=d4*alpha.*x2(1,u);

    w35=w35+dw35
    w45=w45+dw45
    w05=w05+dw05
    w03=w03+dw03
    w13=w13+dw13
    w23=w23+dw23
    w04=w04+dw04
    w14=w14+dw14
    w24=w24+dw24

    i=i+1;  
    alpha=10/(100+i);
                end
    end

         x11=0:0.01:1;
         x22=0:0.01:1;
         L3=w23*x22+w13*x11-w03;
         L4=w24*x22+w14*x11-w04;
         plot(x11,L3,'r')
         hold on
         plot(x11,L4,'g')
         hold on

[Muhammad Adil]

I also wnat to do neural network from scratch, want to make a mathemathical expression form the scratch, here is the methmathical expression of the code to be develop