What is wrong with this matlab program?

I have a homework question about a small-world network. My neuron model is FitzHugh Naguma (electrical coupling). I got this error ??? Error using ==> times Matrix dimensions must agree.

Error in ==> elec_syn_vr_swn at 42 I_syn = ( gsyn.* ( sum((Cshort).*con_mat,2).*x' - con_mat*x' ) )'; and small-world networks matlab codes are true or not? My program is:

%FHN Modeli_VR_Q_e_small-world_networks
clc;clf;clear;

deltat=0.01;
t=250;
j=0;
N=3;
con_mat=ones(N,N)-eye(N);   %all-to-all network
for B=0.0:0.001:0.04
    B
a=1.01;    
j=j+1;      
e=0.01;
A=0.01;                        
ohm=5;    
w=0.1;
x=-0.8*ones(1,3);       
y=-0.2*ones(1,3);
Isyn=zeros(1,3);
gsyn=0.1;  
Qsin=0;  
Qcos=0;

%SMALL_WORLD NETWORKS  
n=50;%number of nodes
k=4;%the nearest neighbor
p=0.5;%coupling probability
r=zeros(1,n);r(2:k+1)=1;r(n-k+1:n)=1;
C=toeplitz(r)
%subplot(2,2,1), spy(C)
%subplot(2,2,2)
v=find(rand(n,1)< p);
Cshort=sparse(v,ceil(n*rand(size(v))),ones(size(v)),n,n)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%5
for i=1:t/deltat
    x=x+deltat.*(x - x.^3/3 -y -Isyn)./e;
    y=y+deltat.*(x +a +A.*cos(w*i*deltat) +B*cos(ohm*i*deltat) );

      I_syn = ( gsyn.* ( sum((Cshort)'.*con_mat,2).*x' - con_mat*x' ) )';

      Qv=x;
      Qv(find(Qv<0))=-1;

      Qvav=(1/N)*sum(Qv);
      Qsin=Qsin+2*Qvav(2)*sin(w*i*deltat);
      Qcos=Qcos+2*Qvav(2)*cos(w*i*deltat);
  end

Qsin=Qsin/(t/deltat);
Qcos=Qcos/(t/deltat);
Qson(j)=sqrt(Qsin^2+Qcos^2);
end

Bplot=0.0:0.001:0.04;
plot(Bplot,Qson,'-o'),
grid on;
xlabel('B');
ylabel('Q');

[Walter Roberson]

What difference do you observe between what you expect and what you get? Are you receiving an error message?

Answer 1

[Paul]

The Line

sum((Cshort)'.*con_mat,2)

is what is causing your error.

Matlab uses matrix multiplication these matrices are not able to be multiplied together and so will cause an error.

Check your working to see if you have created these matrices correctly. What are they superposed to be ?