C Library Functions - wgedi (3)
NAME
WGEDI(3f) - [M_LA] computes the determinant and inverse of a matrix using the factors computed by WGECO(3f) or WGEFA(3f).
CONTENTS
Synopsis
Description
On Entry
On Return
Error Condition
Subroutines And Functions
SYNOPSIS
SUBROUTINE ML_WGEDI(AR,AI,LDA,N,IPVT,DETR,DETI,WORKR,WORKI,JOB)
INTEGER(KIND=4) :: LDA REAL(KIND=8) :: AR(LDA,*) REAL(KIND=8) :: AI(LDA,*) INTEGER(KIND=4) :: N INTEGER(KIND=4) :: IPVT(*) REAL(KIND=8) :: DETR(2) REAL(KIND=8) :: DETI(2) REAL(KIND=8) :: WORKR(*) REAL(KIND=8) :: WORKI(*) INTEGER(KIND=4) :: JOB
DESCRIPTION
WGEDI(3f) computes the determinant and inverse of a matrix using the factors computed by WGECO(3f) or WGEFA(3f).
ON ENTRY
A Double-Complex(LDA, N) The output from WGECO or WGEFA. LDA Integer The leading dimension of the array A. N Integer The order of the matrix A. IPVT Integer(N) The pivot vector from WGECO(3f) or WGEFA(3f). WORK Double-Complex(N) Work vector. Contents destroyed. JOB Integer = 11 Both determinant and inverse. = 01 Inverse only. = 10 Determinant only.
ON RETURN
A Inverse of original matrix if requested. Otherwise unchanged. DET Double-complex(2) Determinant of original matrix if requested. Otherwise not referenced. DETERMINANT = DET(1) * 10.0**DET(2) with 1.0 .le. CABS1(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 WGECO(3f) has set RCOND [char46]gt. 0.0 or WGEFA(3f) has set INFO .eq. 0 .
LINPACK. THIS VERSION DATED 07/01/79 . CLEVE MOLER, UNIVERSITY OF NEW MEXICO, ARGONNE NATIONAL LAB.
SUBROUTINES AND FUNCTIONS
BLAS WAXPY,mat_wscal,mat_wswap FORTRAN DABS,MOD
| Nemo Release 3.1 | wgedi (3) | July 22, 2023 |
