how can i covert following variables as Indexed variables ?

1 次查看（过去 30 天）
Raihan Ul Islam
Raihan Ul Islam 2019-9-6
评论： Raihan Ul Islam 2019-9-8
I have following function. I want to improve the execution time. Matlab profiler is showing following messgae. How can i convert 'input' and 'transformedRefVal1Rt' as indexed variables.
If 'input' is an indexed variable, performance can be improved using logical indexing instead of FIND.
If 'transformedRefVal1Rt' is an indexed variable, performance can be improved using logical indexing instead of FIND.
Here Input is 1x49457 and RtRef is 1x3 Matrix. I am also attaching the data of input,RtRef,numberOfInputData
function transformedRefVal1Rt=inputTransformGPU(input,RtRef,numberOfInputData)
[M,N]=size(RtRef);
transformedRefVal1Rt=gpuArray(zeros(numberOfInputData,N));
input(find(input>RtRef(1)))=RtRef(1);
input(find(input<RtRef(N)))=RtRef(N);
for j=1:N
transformedRefVal1Rt(find(input== RtRef(j)),j)=1;
end
for j=1:N-1
aa=find((RtRef(j)> input ) & (input>RtRef(j+1)));
transformedRefVal1Rt(aa,j+1)=(RtRef(j)-input(aa))/(RtRef(1)-RtRef(j+1));
transformedRefVal1Rt(aa,j)=1-transformedRefVal1Rt(aa,j+1);
end
end

请先登录，再回答此问题。

采纳的回答

Rik
Rik 2019-9-6
No need for a conversion, they already are indexed variables. Lets give a small example of what this message means:
data=1:5;
L= data<2.5; %generate logical array [true true false false false]
ind=find(L); %generate linear index [1 2]
data(ind) %returns [1 2]
data(L) %returns [1 2]
Because you skip a function call if you directly use the logical array to index you get a performance gain.
In your case you can simply remove the find calls, even without needing to edit any other part of your code.
  5 个评论
显示 3更早的评论
Rik
Rik 2019-9-8
With such a low loop count I doubt you will see much gain in vectorizing this code. I also don't really see a way to vectorize this function, although I expect it can be done.
In case your question is what I mean with vectorization:
a=1:10;
for n=1:9
if mod(a(n),3)==0
a(n)=a(n+1);
end
end
%vectorized:
b=1:10;
L1=mod(b,3)==0;
L2=[false L1(1:(end-1))];
b(L1)=b(L2);

请先登录，再进行评论。

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Loops and Conditional Statements 的更多信息

标签

产品


版本

R2018b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by