Computing A(:, m)*B(m, :) without a for loop

1 Ansicht (letzte 30 Tage)
Nicolas Perez
Nicolas Perez am 12 Nov. 2018
Kommentiert: Nicolas Perez am 12 Nov. 2018
Provided I have two matrices A and B of dimensions NxM and MxN I want to compute a matrix C of dimensions NxNxM such that each NxN slice is the result of the prduct A(:, m)*B(m, :). I know this can be obtained in the following way:
for m=1:M
C(:, :, m) = A(:, m)*B(m, :);
end
Is there a way of obtaining the same result without using a for loop (with the aim of making the computation faster)?

Akzeptierte Antwort

Matt J
Matt J am 12 Nov. 2018
Ar=reshape(A,N,1,[]);
Br=reshape(B.',1,N,[]);
C=Ar.*Br;

Weitere Antworten (1)

madhan ravi
madhan ravi am 12 Nov. 2018
C(:, :, 1:M) = A(:, 1:M)*B(1:M, :);
  1 Kommentar
Nicolas Perez
Nicolas Perez am 12 Nov. 2018
The output of A(:, 1:M)*B(1:M, :); is the sum of C(:, :, 1:M) along the third dimension (an NxN matrix). Thus, you get the "Assignment has fewer non-singleton rhs dimensions than non-singleton subscripts" error.

Melden Sie sich an, um zu kommentieren.

Kategorien

Mehr zu Chemistry finden Sie in Help Center und File Exchange

Community Treasure Hunt

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

Start Hunting!

Translated by