Looping through two matrices with IF statement
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[EDIT: Mon May 23 16:36:16 UTC 2011 - Reformat - MKF]
Hello, I am having problems with my for loop statement (see code at bottom). I'm trying to overwrite a zeros matrix (A) with 1's if it meets certain criteria from another matrix (M). It essentially needs to look at M(:,1) and put ones in each row of A (for each numatch) according to the if conditions. Instead of putting ones in the right place, it puts in all ones up to the last numatch row. Here is the code:
%creates A
nx = 5;
ny = 6;
nullnx = zeros(nx,2);
nullny = zeros(ny,2);
nullnx(:,1)=[1:nx];
nullny(:,2)=[1:ny];
if nx >= ny;
numatch = nx;
else
numatch = ny;
end;
if nx >= ny;
x = repmat(nullnx(:,1),nx,1);
matchx = sort(x);
mx = cat(2, matchx, x);
else
x = repmat(nullny(:,2),ny,1);
matchx = sort(x);
mx = cat(2,matchx,x);
end;
M = [nullnx;nullny;mx];
A = zeros(nx+ny+numatch,nx+ny+numatch);
%here is where I need help
for i = 1:numatch;
for a = 1:length(M);
for b = 1:length(A);
if M(a, 1)== i;
A(i,b)=1;
end;
end;
end;
end;
Any help is most appreciated
2 个评论
Oleg Komarov
2011-5-23
Please format properly the code: http://www.mathworks.com/matlabcentral/answers/7885-tutorial-how-to-format-your-question
Matt Tearle
2011-5-23
Please format your code.
More importantly, can you please explain what you're expecting? When I run this, I get that M is a 47-by-2 matrix and A is a 17-by-17 matrix. I can't make those numbers match in any obvious way. So please give an example of what you'd expect to see as output, or step us through your algorithm. Here's the start of M:
1 0
2 0
3 0
4 0
5 0
0 1
0 2
0 3
0 4
What should A look like for this?
采纳的回答
Matt Fig
2011-5-23
Your code is doing exactly what you describe that it should do, that is it: "looks at M(:,1) and put ones in each row of A (for each numatch) according to the if condition."
Now is it the case that you need a different IF condition? If so, please show a simple example of input and expected output.
%
%
%
%
EDIT In response to your comment below.
Does this do it?
for ii = 1:numatch;
A(ii,:) = M(:,1)==ii;
end;
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