Using count with negatives

I've written a code (as below), and now i'm trying to count the values of S_coeff_fact, however it won't work for the negative numbers?! I don't know why as ive never had this problem before.

function [S, R] = poly_fact(P, Q)

sizeP = size(P); rowsP = sizeP(2);

sizeQ = size(Q); rowsQ = sizeQ(2);

diff_in_length = rowsP - rowsQ;

i = diff_in_length+1;

count = 0;

while i>0

    i = i-1;

    count = count+1;

    zero_input = zeros(1,diff_in_length);

    Q = [Q zero_input];

    S_coeff_fact = P(1, 1)/Q(1,1);

    Q = Q*S_coeff_fact

P = P - Q

P = P(find(P ~= 0)); % Removing zeros from P.

Q = Q(find(Q ~= 0)); % Removing zeros from Q.

sizeP = size(P); rowsP = sizeP(2);

sizeQ = size(Q); rowsQ = sizeQ(2);

    diff_in_length = rowsP - rowsQ;

    S(count) = count(S_coeff_fact)

end

S = S

R = P

end

[Jessica Parry]

The error is

Attempted to access count(-7); index must be a positive integer or logical.

Error in poly_fact (line 47)

    S(count) = count(S_coeff_fact)

Please help, thanks!

[Image Analyst]

What does " count the values of S_coeff_fact" mean? Do you mean length(S_coeff_fact), or sum(S_coeff_fact)??? Can you put some comments in to explain the code (actually that might help you realize a logic error)? Can you supply some small sample arrays for P and Q so we can try it?

Answer 1

[Jan]

Your variable count is a scalar, such that indexing it with count(S_coeff_fact) must fail for anything but S_coeff_fact == 1. Therefore I claim, that this code did not work properly ever.