LU decomposition in VHDL

Question

I am trying to process LU decomposition in VHDL. I am a starter in VHDL. So I started implementing LU decomposition algorithm in MATLAB.

    a = [1 2 2;3 4 4;5 6 6];
    x=a;
    n=size(x,1);
    l=zeros(n,n);
    u=zeros(n,n);

    for k=1:n
        if (a(k,k)~=0)
            u(k,k)=x(k,k);
            l(k,k)=1;
        for i=k+1:n
            l(i,k)=x(i,k)/x(k,k);
            u(k,i)=x(k,i);
        end

        for i=k+1:n
            for j=k+1:n
                x(i,j)=x(i,j)-(l(i,k)*u(k,j));
            end
        end

        else break
        end

    end

Then I started doing this without for loop because for loop in vhdl doesn't work like matlab. Now, I am facing problem finding the equivalent code for the cascaded for loop.

a = [1 2 2;3 4 4;5 6 6];
x=a;
n=size(x,1);
l=zeros(n,n);
u=zeros(n,n);
k=1;
m=2;
j=2;
p=2;
for clock=1:100
if k>=1 && k<=n
    if (a(k,k)~=0)
        u(k,k)=x(k,k);
        l(k,k)=1;
    else disp('Decomposition not possible')
        return
    end
    if (m>=k+1 && m<=n)
        l(m,k)=x(m,k)/x(k,k);
        u(k,m)=x(k,m);
        m=m+1;
    end

    if p>=k+1 && p<=n
        if j>=k+1 && j<=n
            x(p,j)=x(p,j)-(l(p,k)*u(k,j));
            j=j+1;
        end
        if j==n+1
            p=p+1;
            j=2;
        end
    end    
end
    k=k+1;
end

I know the last code is not equivalent to the previous one. Can someone please help me with some hint on doing this in VHDL?

Answer 1

Captain Obvious to the (title) rescue:

A = [1 2 2;3 4 4;5 6 6];
[L,U] = lu(A);

As for the actual question "can one implement a loop with if/else instead of for/while" (not very well reflected in the title though): yes, it is possible if the language allows goto statements. Loops are basically (un)conditional jumps back in the statement "stream". MATLAB is not one of those languages.

In a C-like language you can implement (declarations aside) a basic for loop like this:

        k = 0;

enter_loop:
        if(k < n) {
                /* here do in-loop stuff */
                k = k+1;
                goto enter_loop;
        }

Note: Your problem seems to be with VHDL. Why don't you change the question tags so VHDL people can answer it directly?