How to multiply row of matrix A with column of matrix B?

7 Ansichten (letzte 30 Tage)
A is 121 x 36 matrix
B is 36 x 121 matrix
The result C should be 121 x 1 matrix.
May I know how should I multiply a row of A with col of B? so that resulting matrix is 121 X 1.
No loops please.
  2 Kommentare
the cyclist
the cyclist am 24 Nov. 2021
One row of A is 36 elements. One column of B is 36 elements. It is absolutely unclear how to get a 121x1 matrix from that.
Please explain more clearly what you need. Perhaps use a smaller example (e.g. 4x3) to show exactly what the input and output should be.
Adam Danz
Adam Danz am 24 Nov. 2021
Prehaps the goal is the multiply a col of A by row of B.

Melden Sie sich an, um zu kommentieren.

Akzeptierte Antwort

James Tursa
James Tursa am 25 Nov. 2021
Bearbeitet: James Tursa am 25 Nov. 2021
Maybe this is what you want?
C = sum(A .* B.',2)

Weitere Antworten (1)

the cyclist
the cyclist am 24 Nov. 2021
If @Adam Danz is correct that you actually want to multiply all the elements of one column of A with one row of B, then
% Define A and B
A = rand(121,36);
B = rand(36,121);
% Which row and column?
colA = 2;
rowB = 3;
% Multiply the selected row and column
V = A(:,colA) .* B(rowB,:).'; % <----- Note that I used the transpose here
% Check the size of V
size(V)
ans = 1×2
121 1

Kategorien

Mehr zu Matrix Indexing finden Sie in Help Center und File Exchange

Produkte


Version

R2021b

Community Treasure Hunt

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

Start Hunting!

Translated by