Extracting positive and negative element of a matrix?

9 views (last 30 days)
Suppose; A= 3D Matrix of size (10,10,10) , where I have some values in positive and some values in negative.
So, with that positive value element I want to multiply it with -1000 and with the negative value element of the matrix A I want to multiply it with 100 and after doing this scaling I want to save them in a new matrix. Can any one help me ?

Accepted Answer

Julius Muschaweck
Julius Muschaweck on 8 Sep 2021
Use logical indexing:
A = rand(10,10, 10) - 0.5; % contains random numbers in [-0.5, 0.5]
B = zeros(10, 10, 10); % preallocating the new matrix.
Aneg = A < 0;
Apos = A > 0; % Aneg and Apos are 10x10x10 logical matrices
B(Apos) = A(Apos) * (-1000); % which you can use to index into an array
B(Aneg) = A(Aneg) * 100;

More Answers (0)


Find more on Resizing and Reshaping Matrices in Help Center and File Exchange

Community Treasure Hunt

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

Start Hunting!

Translated by