apply a function to every element of a square matrix

14 vues (au cours des 30 derniers jours)
Salvatore Mazzarino
Salvatore Mazzarino le 24 Sep 2012
I have a square matrix and I would apply a function to every element of that matrix in the way I get a new square matrix where every element is the result of the function.does it exist a function for the purpose?

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Wayne King
Wayne King le 24 Sep 2012
Modifié(e) : Wayne King le 24 Sep 2012
Yes, arrayfun()
For example:
x = randn(10,10)+1i*randn(10,10);
y = arrayfun(@conj,x);
or
x = randn(10,10);
y = arrayfun(@(x) x.^2,x);
  1 commentaire
Wayne King
Wayne King le 24 Sep 2012
Simon's point is a good one here. Both the examples I gave are easily handled just as:
y = conj(x);
% or for the second
y = x.^2;
I was just illustrating the general use of arrayfun().

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Plus de réponses (2)

Jan
Jan le 24 Sep 2012
Usually arrayfun is not required and wastes time:
x = rand(10, 10);
a = sin(x);
b = x .* x;
c = x .^ 2;

Image Analyst
Image Analyst le 24 Sep 2012
Don't forget other cases, non-point processing cases, where vectorized solutions don't work, and I don't think arrayfun would work easily either. For example area processing operations like Sobel Filter, Savitkzy-Golay filter, morphological operations, adaptive filters, etc. Some of these have special functions to do them, but in general, for your custom operations, you can use functions like conv2(), imfilter(), nlfilter(), blockproc(), etc.

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