pinv function is unknown?

[Joonho Hwang]

mat A = (1,2\2,4\4,8)
mat B = pinv(A)

I'm not familiar with Stata, so this might be a silly question.

If I run this command, I don't know why it says that pinv() is an unknown function.

. mat B = pinv(A)
unknown function pinv()
r(133);

What is wrong with this one? Do I have to install a certain package?

[Nick Cox]

pinv() is a Mata function, not a Stata function.

You can call Mata line by line

or enter Mata and leave when done.

.

 mata: A = (1,2\2,4\4,8)

. mata: B = pinv(A)

. mata: B 
                 1             2             3
    +-------------------------------------------+
  1 |  .0095238095    .019047619   .0380952381  |
  2 |   .019047619   .0380952381   .0761904762  |
    +-------------------------------------------+

. 
. mata 
------------------------------------------------- mata (type end to exit) ------------------------
: A = (1,2\2,4\4,8)

: B = pinv(A)

: B 
                 1             2             3
    +-------------------------------------------+
  1 |  .0095238095    .019047619   .0380952381  |
  2 |   .019047619   .0380952381   .0761904762  |
    +-------------------------------------------+

: end