LAPACK 3.12.0
LAPACK: Linear Algebra PACKage
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◆ ztrsyl3()

subroutine ztrsyl3 ( character  trana,
character  tranb,
integer  isgn,
integer  m,
integer  n,
complex*16, dimension( lda, * )  a,
integer  lda,
complex*16, dimension( ldb, * )  b,
integer  ldb,
complex*16, dimension( ldc, * )  c,
integer  ldc,
double precision  scale,
double precision, dimension( ldswork, * )  swork,
integer  ldswork,
integer  info 
)

ZTRSYL3

Purpose
  ZTRSYL3 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.

  This is the block version of the algorithm.
Parameters
[in]TRANA
          TRANA is CHARACTER*1
          Specifies the option op(A):
          = 'N': op(A) = A    (No transpose)
          = 'C': op(A) = A**H (Conjugate transpose)
[in]TRANB
          TRANB is CHARACTER*1
          Specifies the option op(B):
          = 'N': op(B) = B    (No transpose)
          = 'C': op(B) = B**H (Conjugate transpose)
[in]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
[in]M
          M is INTEGER
          The order of the matrix A, and the number of rows in the
          matrices X and C. M >= 0.
[in]N
          N is INTEGER
          The order of the matrix B, and the number of columns in the
          matrices X and C. N >= 0.
[in]A
          A is COMPLEX*16 array, dimension (LDA,M)
          The upper triangular matrix A.
[in]LDA
          LDA is INTEGER
          The leading dimension of the array A. LDA >= max(1,M).
[in]B
          B is COMPLEX*16 array, dimension (LDB,N)
          The upper triangular matrix B.
[in]LDB
          LDB is INTEGER
          The leading dimension of the array B. LDB >= max(1,N).
[in,out]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.
[in]LDC
          LDC is INTEGER
          The leading dimension of the array C. LDC >= max(1,M)
[out]SCALE
          SCALE is DOUBLE PRECISION
          The scale factor, scale, set <= 1 to avoid overflow in X.
[out]SWORK
          SWORK is DOUBLE PRECISION array, dimension (MAX(2, ROWS),
          MAX(1,COLS)).
          On exit, if INFO = 0, SWORK(1) returns the optimal value ROWS
          and SWORK(2) returns the optimal COLS.
[in]LDSWORK
          LDSWORK is INTEGER
          LDSWORK >= MAX(2,ROWS), where ROWS = ((M + NB - 1) / NB + 1)
          and NB is the optimal block size.

          If LDSWORK = -1, then a workspace query is assumed; the routine
          only calculates the optimal dimensions of the SWORK matrix,
          returns these values as the first and second entry of the SWORK
          matrix, and no error message related LWORK is issued by XERBLA.
[out]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).