Question

I am looking to apply an IF statement to a matrix like the following:

A =

 2     5     2     4     8
 2     5     0     0     0
 2     4     0     0     0
 6     8     0     0     0
 9     5     0     0     0
 4     7     0     0     0
 8     1     0     0     0

What I have so far is this:

if A(1,2)>A(1,4),
A(2,3)=A(1,4);
A(2,4)=(A(1,5))+1;
end


if A(1,2)<A(1,4),
A(2,4)=(A(1,4))-1;
A(2,4)=(A(1,4))-(A(2,3));
end

In the aforementioned code I am only comparing the 2nd and 4th column of the first row.
Then the first row constructs the second row.

I am looking to then compare the second row and use that to construct the third row … and so on … throughout all 7 rows.

Could I add a 1:n to modify this?

Any suggestions?

Answer 1

You can write the following loop

for i=1:size(A, 1)-1
    if A(i,2)>A(i,4),
        A(i+1,3)=A(i,4);
        A(i+1,4)=A(i,5)+1;
    end 
    if A(i,2)<A(i,4),
        A(i+1,4)=A(i,4)-1;
        % wrong index here? You assign twice to the same A entry.
        % the above line has no effect...
        A(i+1,4)=A(i,4)-A(i+1,3);
    end 
end