Add a new pseudo inverse function

[zhuanhao-wu]

It is like the pinv in Matlab,
This is useful when solving some equations and then the solution is something like:
(X'X)^(-1)X'y and X'X is invertible.

This may be the solution to some linear regressions (which I encountered in the machine learning course).

[translunar]

I think this is an excellent idea.

[aelnouby]

@MohawkJohn i want to work on this idea , i am just getting started , so i am not sure where this should be implemented exactly ?

[aelnouby]

Another question , when trying to get the SVD using gesvd just as in the documentation it always outputs "gesvd requires either the nmatrix-atlas or nmatrix-lapacke gem" , i believe atlas and lapacke are installed correctly

What is the best way available to get the SVD ?

[wlevine]

You need to 'require nmatrix/lapacke', but someone has already submitted a pull request for implementing pseudo inverse using gesvd: #471

[aelnouby]

@wlevine i see , sorry i should have checked the PRs first. Any recommendations for a good issue to start with ?

[v0dro]

#410 is pretty simple.