function C=mynifft(A)
%i=1:256;j=1:256;
n=length(A);
B=zeros(n);
unitr=ones(1,n);
unitl=ones(n,1);
for i=1:n
    unitr(1,i)=unitr(1,i)+i-2;
    unitl(i,1)=unitl(i,1)+i-2;
end
for x=1:n
    for y=1:n
        B(x,y)=exp(j*2*pi*(x-1)/n*unitr)*A*exp(j*2*pi*(y-1)/n*unitl)/(n^2);
    end
end
C=B;