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ztrsyl.f(3) LAPACK ztrsyl.f(3)

NAME

ztrsyl.f -

SYNOPSIS

Functions/Subroutines


subroutine ztrsyl (TRANA, TRANB, ISGN, M, N, A, LDA, B, LDB, C, LDC, SCALE, INFO)
ZTRSYL

Function/Subroutine Documentation

subroutine ztrsyl (characterTRANA, characterTRANB, integerISGN, integerM, integerN, complex*16, dimension( lda, * )A, integerLDA, complex*16, dimension( ldb, * )B, integerLDB, complex*16, dimension( ldc, * )C, integerLDC, double precisionSCALE, integerINFO)

ZTRSYL

Purpose:


ZTRSYL solves the complex Sylvester matrix equation:
op(A)*X + X*op(B) = scale*C or
op(A)*X - X*op(B) = scale*C,
where op(A) = A or A**H, and A and B are both upper triangular. A is
M-by-M and B is N-by-N; the right hand side C and the solution X are
M-by-N; and scale is an output scale factor, set <= 1 to avoid
overflow in X.

Parameters:

TRANA


TRANA is CHARACTER*1
Specifies the option op(A):
= 'N': op(A) = A (No transpose)
= 'C': op(A) = A**H (Conjugate transpose)

TRANB


TRANB is CHARACTER*1
Specifies the option op(B):
= 'N': op(B) = B (No transpose)
= 'C': op(B) = B**H (Conjugate transpose)

ISGN


ISGN is INTEGER
Specifies the sign in the equation:
= +1: solve op(A)*X + X*op(B) = scale*C
= -1: solve op(A)*X - X*op(B) = scale*C

M


M is INTEGER
The order of the matrix A, and the number of rows in the
matrices X and C. M >= 0.

N


N is INTEGER
The order of the matrix B, and the number of columns in the
matrices X and C. N >= 0.

A


A is COMPLEX*16 array, dimension (LDA,M)
The upper triangular matrix A.

LDA


LDA is INTEGER
The leading dimension of the array A. LDA >= max(1,M).

B


B is COMPLEX*16 array, dimension (LDB,N)
The upper triangular matrix B.

LDB


LDB is INTEGER
The leading dimension of the array B. LDB >= max(1,N).

C


C is COMPLEX*16 array, dimension (LDC,N)
On entry, the M-by-N right hand side matrix C.
On exit, C is overwritten by the solution matrix X.

LDC


LDC is INTEGER
The leading dimension of the array C. LDC >= max(1,M)

SCALE


SCALE is DOUBLE PRECISION
The scale factor, scale, set <= 1 to avoid overflow in X.

INFO


INFO is INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
= 1: A and B have common or very close eigenvalues; perturbed
values were used to solve the equation (but the matrices
A and B are unchanged).

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

November 2011

Definition at line 157 of file ztrsyl.f.

Author

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Tue Sep 25 2012 Version 3.4.2