.TH "zpttrs.f" 3 "Wed Oct 15 2014" "Version 3.4.2" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME zpttrs.f \- .SH SYNOPSIS .br .PP .SS "Functions/Subroutines" .in +1c .ti -1c .RI "subroutine \fBzpttrs\fP (UPLO, N, NRHS, D, E, B, LDB, INFO)" .br .RI "\fI\fBZPTTRS\fP \fP" .in -1c .SH "Function/Subroutine Documentation" .PP .SS "subroutine zpttrs (characterUPLO, integerN, integerNRHS, double precision, dimension( * )D, complex*16, dimension( * )E, complex*16, dimension( ldb, * )B, integerLDB, integerINFO)" .PP \fBZPTTRS\fP .PP \fBPurpose: \fP .RS 4 .PP .nf ZPTTRS solves a tridiagonal system of the form A * X = B using the factorization A = U**H *D* U or A = L*D*L**H computed by ZPTTRF. D is a diagonal matrix specified in the vector D, U (or L) is a unit bidiagonal matrix whose superdiagonal (subdiagonal) is specified in the vector E, and X and B are N by NRHS matrices. .fi .PP .RE .PP \fBParameters:\fP .RS 4 \fIUPLO\fP .PP .nf UPLO is CHARACTER*1 Specifies the form of the factorization and whether the vector E is the superdiagonal of the upper bidiagonal factor U or the subdiagonal of the lower bidiagonal factor L. = 'U': A = U**H *D*U, E is the superdiagonal of U = 'L': A = L*D*L**H, E is the subdiagonal of L .fi .PP .br \fIN\fP .PP .nf N is INTEGER The order of the tridiagonal matrix A. N >= 0. .fi .PP .br \fINRHS\fP .PP .nf NRHS is INTEGER The number of right hand sides, i.e., the number of columns of the matrix B. NRHS >= 0. .fi .PP .br \fID\fP .PP .nf D is DOUBLE PRECISION array, dimension (N) The n diagonal elements of the diagonal matrix D from the factorization A = U**H *D*U or A = L*D*L**H. .fi .PP .br \fIE\fP .PP .nf E is COMPLEX*16 array, dimension (N-1) If UPLO = 'U', the (n-1) superdiagonal elements of the unit bidiagonal factor U from the factorization A = U**H*D*U. If UPLO = 'L', the (n-1) subdiagonal elements of the unit bidiagonal factor L from the factorization A = L*D*L**H. .fi .PP .br \fIB\fP .PP .nf B is DOUBLE PRECISION array, dimension (LDB,NRHS) On entry, the right hand side vectors B for the system of linear equations. On exit, the solution vectors, X. .fi .PP .br \fILDB\fP .PP .nf LDB is INTEGER The leading dimension of the array B. LDB >= max(1,N). .fi .PP .br \fIINFO\fP .PP .nf INFO is INTEGER = 0: successful exit < 0: if INFO = -k, the k-th argument had an illegal value .fi .PP .RE .PP \fBAuthor:\fP .RS 4 Univ\&. of Tennessee .PP Univ\&. of California Berkeley .PP Univ\&. of Colorado Denver .PP NAG Ltd\&. .RE .PP \fBDate:\fP .RS 4 September 2012 .RE .PP .PP Definition at line 122 of file zpttrs\&.f\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.