## The values

*Wi*are zero or positive and are called the "singular values".## The NRiC routine svdcmp() returns

*U*,*V*, &*W*given*A*. You have to trust it (or test it yourself!).- Uses Householder reduction, QR diagonalization, etc.

## If

*A*is square then we know:*A*-1 =*V*[diag(1/*Wi*)]*U T*

## This is fine so long as no

*Wi*is too small (or 0).