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ctrsyl.f(3) LAPACK ctrsyl.f(3)

NAME

ctrsyl.f -

SYNOPSIS

Functions/Subroutines


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

Function/Subroutine Documentation

subroutine ctrsyl (characterTRANA, characterTRANB, integerISGN, integerM, integerN, complex, dimension( lda, * )A, integerLDA, complex, dimension( ldb, * )B, integerLDB, complex, dimension( ldc, * )C, integerLDC, realSCALE, integerINFO)

CTRSYL
Purpose:
 CTRSYL 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 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 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 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 REAL
          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 ctrsyl.f.

Author

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