From: Rich Mattes <jpgr87@gm...>  20121219 22:44:57

On 12/17/2012 12:45 PM, Toon Van Assche wrote: > Dear all, > > Running Stage 4.1.1 & Player v.3.1.0svn @ Ubuntu 12.04 LTS. > I would like to take the inverse of a nxn matrix to use in my GraphSlam. > > The issues that I encountered: >  .inverse() Eigenlibrary (3.1.2) doesn't allow zero values, returns NaN >  The LAPACK (3.4.2) library doesn't allow to use negative values, > allows zero values > (used this example code > http://stackoverflow.com/questions/3519959/computingtheinverseofamatrixusinglapackinc) > >  Pseudo inversion doesn't seem to allow negative values either >  Seldon (5.1.2) wouldn't compile for some reason > > Did anyone successfully implemented an nxn matrix inversion code that > allows negative and zerovalues. > Any good library recommendations? > > All help would be appreciated, > > Regards, > > Toon > Can you provide an example of a matrix you're trying to invert that isn't working? The presence of zeros or negative numbers doesn't necessarily have any bearing on a matrix's invertiblity, but if you're trying to invert a singular matrix or a matrix that isn't full rank then you're going to have issues no matter what library you use. Rich 