STRDI(3F)
STRDI - STRDI computes the determinant and inverse of a real triangular matrix.
As shipped in IRIX 6.5.15. Unchanged since IRIX 6.5.
NAME STRDI - STRDI computes the determinant and inverse of a real triangular matrix. SYNOPSYS SUBROUTINE STRDI(T,LDT,N,DET,JOB,INFO) DESCRIPTION On Entry T REAL(LDT,N) T contains the triangular matrix. The zero elements of the matrix are not referenced, and the corresponding elements of the array can be used to store other information. LDT INTEGER LDT is the leading dimension of the array T. N INTEGER N is the order of the system. JOB INTEGER = 010 no det, inverse of lower triangular. = 011 no det, inverse of upper triangular. = 100 det, no inverse. = 110 det, inverse of lower triangular. = 111 det, inverse of upper triangular. On Return T inverse of original matrix if requested. Otherwise unchanged. DET REAL(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 . INFO INTEGER INFO contains zero if the system is nonsingular and the inverse is requested. Otherwise INFO contains the index of a zero diagonal element of T. LINPACK. This version dated 08/14/78 . Cleve Moler, University of New Mexico, Argonne National Lab. Subroutines and Functions BLAS SAXPY,SSCAL Fortran ABS,MOD