MATLAB Answers

ARGY B
0

How to avoid for loop, when using ecdf for a matrix?

Asked by ARGY B
on 21 Aug 2019 at 20:02
Latest activity Commented on by ARGY B
on 21 Aug 2019 at 20:23
Is there a smarter way to create a matrix fx and a matrix x without using the for loop?
for i=1:4
[fx(:,i) x(:,i)]= ecdf(A(index(i),:));
end
A : a matrix (size 100000x10000)
and index is
index =
7307
21917
40179
58441
I just want the four ecdf results for only the four rows I chose (using the variable named index).
For example the following does not work:
[fx x]= ecdf(A(index,:));

  0 Comments

Sign in to comment.

1 Answer

Answer by the cyclist
on 21 Aug 2019 at 20:16
Edited by the cyclist
on 21 Aug 2019 at 20:17
 Accepted Answer

No. Inside the code for ecdf.m, you can see the line that explicitly creates an error message if the input is not a vector. I won't post the actual code, but you can do
type ecdf.m
to see for yourself. (The line is near the top of the file, and commented.)
If you wanted to, I suppose you could create your own "parallelized" version of ecdf (by copying and editing ecdf), in which you loop through your matrix internally within your new function. But that has its own inelegancies.

  1 Comment

You are right. I checked it out.
Thank you

Sign in to comment.