SPPDI(3F)
SPPDI - SPPDI computes the determinant and inverse of a real symmetric positive definite matrix using the factors computed by SPPCO or SPPFA .
As shipped in IRIX 6.5. First release of IRIX 6.5.
NAME SPPDI - SPPDI computes the determinant and inverse of a real symmetric positive definite matrix using the factors computed by SPPCO or SPPFA . SYNOPSYS SUBROUTINE SPPDI(AP,N,DET,JOB) DESCRIPTION On Entry AP REAL (N*(N+1)/2) the output from SPPCO or SPPFA. N INTEGER the order of the matrix A . JOB INTEGER = 11 both determinant and inverse. = 01 inverse only. = 10 determinant only. On Return AP the upper triangular half of the inverse . The strict lower triangle is unaltered. DET REAL(2) determinant of original matrix if requested. Otherwise not referenced. Determinant = DET(1) * 10.0**DET(2) with 1.0 .LE. DET(1) .LT. 10.0 or DET(1) .EQ. 0.0 . Error Condition A division by zero will occur if the input factor contains a zero on the diagonal and the inverse is requested. It will not occur if the subroutines are called correctly and if SPOCO or SPOFA has set INFO .EQ. 0 . LINPACK. This version dated 08/14/78 . Cleve Moler, University of New Mexico, Argonne National Lab. Subroutines and Functions BLAS SAXPY,SSCAL Fortran MOD