Mata : Matrix Multiplication

[Jay Dev]

Hi STATA users

Trying to evaluate an index using mata. I am unable to understand why the comfortability error is arising

mata

X = st_data(.,("price","weight","length"))
a = st_matrix("L") /*Where L is 3x3 matrix obtained from a estimation command*/
X = X:*a

<istmt>: 3200 conformability error

[Nick Cox]

You are asking for elementwise multiplication, which you don't want.

X * a

is code for matrix multiplication.

[Jay Dev]

Thanks a lot, Nick. I am attempting textbook matrix multiplication.
This way, it's working.
But what is the difference ?

Actually, I got it!!!

Thanks a lot Nick