SRC/strsyl.f(3)            Library Functions Manual            SRC/strsyl.f(3)

NAME
       SRC/strsyl.f

SYNOPSIS
   Functions/Subroutines
       subroutine strsyl (trana, tranb, isgn, m, n, a, lda, b, ldb, c, ldc,
           scale, info)
           STRSYL

Function/Subroutine Documentation
   subroutine strsyl (character trana, character tranb, integer isgn, integer
       m, integer n, real, dimension( lda, * ) a, integer lda, real,
       dimension( ldb, * ) b, integer ldb, real, dimension( ldc, * ) c,
       integer ldc, real scale, integer info)
       STRSYL

       Purpose:


           !>
           !> STRSYL solves the real 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**T, and  A and B are both upper quasi-
           !> 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.
           !>
           !> A and B must be in Schur canonical form (as returned by SHSEQR), that
           !> is, block upper triangular with 1-by-1 and 2-by-2 diagonal blocks;
           !> each 2-by-2 diagonal block has its diagonal elements equal and its
           !> off-diagonal elements of opposite sign.
           !>

       Parameters
           TRANA

           !>          TRANA is CHARACTER*1
           !>          Specifies the option op(A):
           !>          = 'N': op(A) = A    (No transpose)
           !>          = 'T': op(A) = A**T (Transpose)
           !>          = 'C': op(A) = A**H (Conjugate transpose = Transpose)
           !>

           TRANB

           !>          TRANB is CHARACTER*1
           !>          Specifies the option op(B):
           !>          = 'N': op(B) = B    (No transpose)
           !>          = 'T': op(B) = B**T (Transpose)
           !>          = 'C': op(B) = B**H (Conjugate transpose = 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 REAL array, dimension (LDA,M)
           !>          The upper quasi-triangular matrix A, in Schur canonical form.
           !>

           LDA

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

           B

           !>          B is REAL array, dimension (LDB,N)
           !>          The upper quasi-triangular matrix B, in Schur canonical form.
           !>

           LDB

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

           C

           !>          C is REAL 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.

       Definition at line 162 of file strsyl.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0                 SRC/strsyl.f(3)