DGEDI(3)

SYNOPSIS
SUBROUTINE DGEDI (A, LDA, N, IPVT, DET, WORK, JOB)

NAME
dgedi - Compute the determinant and inverse of a matrix using the factors computed by DGECO or DGEFA.

LIBRARY
SLATEC (LINPACK)

CATEGORY
D3A1, D2A1

TYPE
DOUBLE PRECISION (SGEDI-S, DGEDI-D, CGEDI-C)

KEYWORDS
DETERMINANT, INVERSE, LINEAR ALGEBRA, LINPACK, MATRIX

AUTHOR
Moler, C. B., (U. of New Mexico)

DESCRIPTION
DGEDI computes the determinant and inverse of a matrix using the factors computed by DGECO or DGEFA. On Entry A DOUBLE PRECISION(LDA, N) the output from DGECO or DGEFA. LDA INTEGER the leading dimension of the array A . N INTEGER the order of the matrix A . IPVT INTEGER(N) the pivot vector from DGECO or DGEFA. WORK DOUBLE PRECISION(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 PRECISION(2) determinant of original matrix if requested. Otherwise not referenced. Determinant = DET(1) * 10.0**DET(2) with 1.0 .LE. ABS(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 DGECO has set RCOND .GT. 0.0 or DGEFA has set INFO .EQ. 0 .

REFERENCES
J. J. Dongarra, J. R. Bunch, C. B. Moler, and G. W. Stewart, LINPACK Users' Guide, SIAM, 1979.

ROUTINES CALLED
DAXPY, DSCAL, DSWAP

REVISION HISTORY (YYMMDD)
780814 DATE WRITTEN
890531 Changed all specific intrinsics to generic. (WRB)
890831 Modified array declarations. (WRB)
890831 REVISION DATE from Version 3.2
891214 Prologue converted to Version 4.0 format. (BAB)
900326 Removed duplicate information from DESCRIPTION section. (WRB)
920501 Reformatted the REFERENCES section. (WRB)