slaDmat -

SYNOPSYS

PARAMETERS

int n

double *a

double *y

double *d

int *jf

int *iw

DESCRIPTION

  Matrix inversion & solution of simultaneous equations.

  (double precision)

For the set of n simultaneous equations in n unknowns

     a.y = x

where

     a is a non-singular n x n matrix
     y is the vector of n unknowns
     x is the known vector

slaDmatt computes

     the inverse of matrix a
     the determinant of matrix a
     the vector of n unknowns

Arguments

     symbol  type dimension           before              after

       n      int                  no. of unknowns       unchanged
       a      double  [n][n]           matrix             inverse
       y      double   [n]              vector            solution
      *d      double                      -             determinant
    > *jf     int                         -           singularity flag
       iw     int      [n]                -              workspace


    >  jf is the singularity flag.  If the matrix is non-singular,
       jf=0 is returned.  If the matrix is singular, jf=-1 & d=0.0 are
       returned.  In the latter case, the contents of array a on return
       are undefined.

Algorithm

     Gaussian elimination with partial pivoting.

Speed

     Very fast.

Accuracy

     Fairly accurate - errors 1 to 4 times those of routines optimized
     for accuracy.

  J.O.Straede   AAO  April 1993
  P.T.Wallace   Starlink   31 October 1993

SEE ALSO

• slalib.3