CTRSL(3)

SYNOPSIS
SUBROUTINE CTRSL (T, LDT, N, B, JOB, INFO)

NAME
ctrsl - Solve a system of the form T*X=B or CTRANS(T)*X=B, where T is a triangular matrix. Here CTRANS(T) is the conjugate transpose.

LIBRARY
SLATEC (LINPACK)

CATEGORY
D2C3

TYPE
COMPLEX (STRSL-S, DTRSL-D, CTRSL-C)

KEYWORDS
LINEAR ALGEBRA, LINPACK, TRIANGULAR LINEAR SYSTEM, TRIANGULAR MATRIX

AUTHOR
Stewart, G. W., (U. of Maryland)

DESCRIPTION
CTRSL solves systems of the form T * X = B or CTRANS(T) * X = B where T is a triangular matrix of order N. Here CTRANS(T) denotes the conjugate transpose of the matrix T. On Entry T COMPLEX(LDT,N) T contains the matrix of the system. The zero elements of the matrix are not referenced, and the corresponding elements of the array can be used to store other information. LDT INTEGER LDT is the leading dimension of the array T. N INTEGER N is the order of the system. B COMPLEX(N). B contains the right hand side of the system. JOB INTEGER JOB specifies what kind of system is to be solved. If JOB is 00 solve T*X = B, T lower triangular, 01 solve T*X = B, T upper triangular, 10 solve CTRANS(T)*X = B, T lower triangular, 11 solve CTRANS(T)*X = B, T upper triangular. On Return B B contains the solution, if INFO .EQ. 0. Otherwise B is unaltered. INFO INTEGER INFO contains zero if the system is nonsingular. Otherwise INFO contains the index of the first zero diagonal element of T.

REFERENCES
J. J. Dongarra, J. R. Bunch, C. B. Moler, and G. W. Stewart, LINPACK Users' Guide, SIAM, 1979.

ROUTINES CALLED
CAXPY, CDOTC

REVISION HISTORY (YYMMDD)
780814 DATE WRITTEN
890831 Modified array declarations. (WRB)
890831 REVISION DATE from Version 3.2
891214 Prologue converted to Version 4.0 format. (BAB)
900326 Removed duplicate information from DESCRIPTION section. (WRB)
920501 Reformatted the REFERENCES section. (WRB)