Find the minimums along 3rd dimension of an array

10 views (last 30 days)
I have a 3d array that is constructed from two 2d arrays:
a = [1 2 3; 4 5 6; 7 8 9];
b = [1 2 0; 4 0 9; 9 8 9];
c = cat(3,a,b);
I want to find the minimums along dimension 3 only.
Desired output:
c_mins =
1 2 0
4 0 6
7 8 9
I thought this would work but it seems to give a different result which I don't understant:
min(c, 3)
ans(:,:,1) =
1 2 3
3 3 3
3 3 3
ans(:,:,2) =
1 2 0
3 0 3
3 3 3

Accepted Answer

Image Analyst
Image Analyst on 9 Dec 2021
You need [] in min():
a = [1 2 3; 4 5 6; 7 8 9];
b = [1 2 0; 4 0 9; 9 8 9];
c = cat(3,a,b)
c =
c(:,:,1) = 1 2 3 4 5 6 7 8 9 c(:,:,2) = 1 2 0 4 0 9 9 8 9
minValues = min(c, [], 3)
minValues = 3×3
1 2 0 4 0 6 7 8 9
  3 Comments
Image Analyst
Image Analyst on 10 Dec 2021
@Bill Tubbs, yeah, sometimes there are inconsistencies like that.
Steven Lord
Steven Lord on 10 Dec 2021
If I recall correctly the syntax min(A, B) predates the introduction of 3-dimensional arrays into MATLAB (both of which predate the start of my tenure at MathWorks.) We don't want min(A, scalar) to be ambiguous if the scalar is a potential dimension number so we instead treat it always as B.

Sign in to comment.

More Answers (0)

Categories

Find more on Creating and Concatenating Matrices in Help Center and File Exchange

Tags

Products


Release

R2020a

Community Treasure Hunt

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

Start Hunting!