.TH ZTRTI2 1 "November 2006" " LAPACK routine (version 3.1) " " LAPACK routine (version 3.1) " .SH NAME ZTRTI2 - the inverse of a complex upper or lower triangular matrix .SH SYNOPSIS .TP 19 SUBROUTINE ZTRTI2( UPLO, DIAG, N, A, LDA, INFO ) .TP 19 .ti +4 CHARACTER DIAG, UPLO .TP 19 .ti +4 INTEGER INFO, LDA, N .TP 19 .ti +4 COMPLEX*16 A( LDA, * ) .SH PURPOSE ZTRTI2 computes the inverse of a complex upper or lower triangular matrix. This is the Level 2 BLAS version of the algorithm. .br .SH ARGUMENTS .TP 8 UPLO (input) CHARACTER*1 Specifies whether the matrix A is upper or lower triangular. = \(aqU\(aq: Upper triangular .br = \(aqL\(aq: Lower triangular .TP 8 DIAG (input) CHARACTER*1 Specifies whether or not the matrix A is unit triangular. = \(aqN\(aq: Non-unit triangular .br = \(aqU\(aq: Unit triangular .TP 8 N (input) INTEGER The order of the matrix A. N >= 0. .TP 8 A (input/output) COMPLEX*16 array, dimension (LDA,N) On entry, the triangular matrix A. If UPLO = \(aqU\(aq, the leading n by n upper triangular part of the array A contains the upper triangular matrix, and the strictly lower triangular part of A is not referenced. If UPLO = \(aqL\(aq, the leading n by n lower triangular part of the array A contains the lower triangular matrix, and the strictly upper triangular part of A is not referenced. If DIAG = \(aqU\(aq, the diagonal elements of A are also not referenced and are assumed to be 1. On exit, the (triangular) inverse of the original matrix, in the same storage format. .TP 8 LDA (input) INTEGER The leading dimension of the array A. LDA >= max(1,N). .TP 8 INFO (output) INTEGER = 0: successful exit .br < 0: if INFO = -k, the k-th argument had an illegal value