Making a code runs faster

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Ronaldo
Ronaldo 2013-9-2
How can I make the following code runs faster (This a part of a larger code). I do not want to use parfor.
for rotation=1:360
RHO(:,1)=(CL*Landa)./T(tnum).LoAn(:,1);
THETA=T(tnum).LoAn(:,3);
X(:,1)=RHO.*cos(deg2rad(THETA(:,1)+rotation));
Y(:,1)=RHO.*sin(deg2rad(THETA(:,1)+rotation));
XP=round(72+X);
YP=round(72+Y);
mat=zeros(144,144);
for i=1:size(XP,1)
a=XP(i,1);
b=YP(i,1);
if a>0 & a<145 & b>0 & b<145
mat(a,b)= T(tnum).LoAn(i,2);
end
end
end
  2 个评论
Walter Roberson
Walter Roberson 2013-9-2
Isn't your RHO the same for each iteration? If so then compute it outside the loop. Same for THETA.
To confirm: LoAn is a 2D array, and not just a row vector ? so size(LoAn,1) > 1 ?
Roger Stafford
Roger Stafford 2013-9-2
It looks as though your purpose in this code is to set up the array 'mat'. However, on each trip through the outer for-loop this array is completely erased and refilled with the information from the next 'rotation' angle. What is the sense in that? Only the last 360 degree angle would have any effect on the final values in 'mat'. Is it possible you are doing something with 'mat' which you haven't shown here before returning for another rotation angle? We need to know such things if we are to help you effectively.

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回答（1 个）

Azzi Abdelmalek
Azzi Abdelmalek 2013-9-2
编辑：Azzi Abdelmalek 2013-9-2
  1 个评论
Ronaldo
Ronaldo 2013-9-2
In other part of the code, I did pre-allocating. I like to make more parallel calculations. Since I am going to use spmd, I try to avoid parfor loops.

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