vector multiplied a matrix

2 views (last 30 days)
Paul Rogers
Paul Rogers on 11 Jun 2020
Commented: the cyclist on 11 Jun 2020
Hi, I need this multiplication and I can't whats wrong
f=c.*T
where c and T are the attached files.
so I expect a raw vector f where:
f_11 = c_11*T_11 + c_12*T_21 + c_13*T_31 + c_14*T_41 + c_15*T_51;
f_12= c_11*T_12 + c_12*T_22 + c_13*T_32 + c_14*T_42 + c_15*T_52;
and so on.
It's really stupid i know, but I can''t figured out why it's not working.
c has 1 colum and 5 rows, T has 101 colums and 5 rows.
  4 Comments
James Tursa
James Tursa on 11 Jun 2020
Your notation is confusing. You say c has 5 rows and 1 column, yet you use c_12 in your example indicating it has 1 row and 5 columns.

Sign in to comment.

Accepted Answer

James Tursa
James Tursa on 11 Jun 2020
Edited: James Tursa on 11 Jun 2020
Maybe this is what you want if c is 5 x 1 and T is 5 x 101:
f = c.' * T;

More Answers (1)

the cyclist
the cyclist on 11 Jun 2020
If your version of MATLAB is older than R2016b, then c will not be "implicitly expanded" to the size of T. You can do the following to get what you want:
f = bsxfun(@times,c,T)
  2 Comments
Paul Rogers
Paul Rogers on 11 Jun 2020
I've just did it but I expeted f to be a raw not a matrix.
the cyclist
the cyclist on 11 Jun 2020
Sorry, I missed that you wanted the sum. What you want is actually a matrix multiplication, not an element-wise multiplication, which is the syntax you were trying to use. I think you want this:
f = T'*c;

Sign in to comment.

Categories

Find more on Matrices and Arrays in Help Center and File Exchange

Products


Release

R2014b

Community Treasure Hunt

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

Start Hunting!