Nested loop error help
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Hello!
I guess this should be super obvious and simple for almost everyone...but for some reason I can't make this nested for loop to work:
I get this error and I'm not sure why: Attempted to access b(1,7); index must be a positive integer or logical.
b = zeros(51,11);
for i = 0:0.01:0.5
for j = 0:0.1:1
a = (2*i)+j;
p = (j/0.1)+1;
q = (i/0.01)+1;
b(q,p)= a;
end
end
Thanks!
采纳的回答
Azzi Abdelmalek
2014-3-15
编辑：Azzi Abdelmalek
2014-3-15
EDIT
b = zeros(51,11);
for i = 0:0.01:0.5
for j = 0:0.1:1
a = (2*i)+j;
p = round((j/0.1)+1);
q = round((i/0.01)+1);
b(q,p)= a;
end
end
3 个评论
Image Analyst
2014-3-15
Amir, be aware, fix() truncates the fractional part so that if you're just slightly under the integer number, you'll go down one whole integer. that's why I used int32(), which is a rounding like you're familiar with followed by a cast to an integer class. See this demo code:
p=[1.01, 2.99999]
fp = fix(p)
rp = int32(p)
p = 1.01 2.99999
fp = 1 2
rp = 1 3
That's why I suggested int32() instead of fix() in my naswer.
Amir Alansari
2014-3-15
编辑：Amir Alansari
2014-3-15
Azzi Abdelmalek
2014-3-15
Using fix is a bad idea, you can replace it with round
更多回答（2 个）
Image Analyst
2014-3-15
Try this:
b = zeros(51,11);
for i = 0:0.01:0.5
for j = 0:0.1:1
a = (2*i)+j;
p = int32(10*j+1);
q = int32(100*i+1);
b(q,p)= a;
end
end
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