Solving Mathematical Relation Having If and Else Statement in Matlab

Hi,

Here I am writing a mathematical relation which is needed to be solved using Matlab:

N=4;
j=sqrt(-1);

Sx=[27 0 4 19;
  19 -8 -10 16;
  20 -4 -7 9;
  27 0 2 24];

Sy=[22 4 -7 -25;
  7 2 -8 -12;
  -8 -5 3 5;
  -23 -9 5 13];

P(k,l)={0; if k,l=0 and k,l=N/2
      {((exp(-j*2*pi*k)/N)-1)*((exp(-j*2*pi*l)/N)+1)*DFT(Sx(k,l)+
      ((exp(-j*2*pi*l)/N)-1)*((exp(-j*2*pi*k)/N)+1)*DFT(Sy(k,l)}*
      {8*((sin(k*pi/N).^2)*(cos(l*pi/N).^2)+(sin(l*pi/N).^2)*(cos(k*pi/N).^2)}.^(-1), else

        where k and l varies from 1 to 4 each

********** Can anyone please help me in solving the above problem with the help of Matlab? Thanking You!

[Walter Roberson]

Please clarify what you mean by "solving the above problem" ? You do not appear to have any free variables, so do you just mean how to write the code to construct P ?

[Pranjal Pathak]

Sorry, as I did not post it specifically. Yes, I do mean how to write the code to construct P. Also, here DFT- Discrete Fourier Transform.

Thanks.

[Image Analyst]

What variable(s) are you solving for? What is the unknown(s)?

[Pranjal Pathak]

I need to write a code to solve for the variable P(k,l).

Thanks.

Answer 1

[Image Analyst]

Well you are practically there already. Just put that code in a loop over k and l (l is a bad variable name choice). Inside the loop have the if statements where you assign P(k,l) to different things depending on what the values of k and l are.

[Pranjal Pathak]

Thanks a lot for your suggestions. I tried, but it is showing some error when I run it. Could you please figure out the problem? Here is the code:

Sx=[27 0 4 19; 19 -8 -10 16; 20 -4 -7 9; 27 0 2 24];

Sy=[22 4 -7 -25; 7 2 -8 -12; -8 -5 3 5; -23 -9 5 13];

n=4; j=sqrt(-1);

P=zeros(n,n); for k=1:n for m=1:n Ftx=fft2(Sx); Fty=fft2(Sy);

            if((k == 0 | m == 0) & (k == n/2 | m  == n/2))
                P(k,m)=0;
            else
                P(k,m)=((((exp(-j*2*pi*k)/n)-1)*((exp(-j*2*pi*m)/n)+1)*Ftx)+(((exp(-j*2*pi*m)/n)-1)*((exp(-j*2*pi*k)/n)+1)*Fty)*(8*((sin(k*pi/n)^2)*(cos(m*pi/n)^2)+(sin(m*pi/n)^2)*(cos(k*pi/n)^2))^(-1)));
            end
        end
    end

P(k,m); *************** Thanks.

[Walter Roberson]

What error is it showing ?