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SUBROUTINE STRSL(T,LDT,N,B,JOB,INFO)
INTEGER LDT,N,JOB,INFO
REAL T(LDT,1),B(1)
C
C
C STRSL SOLVES SYSTEMS OF THE FORM
C
C T * X = B
C OR
C TRANS(T) * X = B
C
C WHERE T IS A TRIANGULAR MATRIX OF ORDER N. HERE TRANS(T)
C DENOTES THE TRANSPOSE OF THE MATRIX T.
C
C ON ENTRY
C
C T REAL(LDT,N)
C T CONTAINS THE MATRIX OF THE SYSTEM. THE ZERO
C ELEMENTS OF THE MATRIX ARE NOT REFERENCED, AND
C THE CORRESPONDING ELEMENTS OF THE ARRAY CAN BE
C USED TO STORE OTHER INFORMATION.
C
C LDT INTEGER
C LDT IS THE LEADING DIMENSION OF THE ARRAY T.
C
C N INTEGER
C N IS THE ORDER OF THE SYSTEM.
C
C B REAL(N).
C B CONTAINS THE RIGHT HAND SIDE OF THE SYSTEM.
C
C JOB INTEGER
C JOB SPECIFIES WHAT KIND OF SYSTEM IS TO BE SOLVED
C IF JOB IS
C
C 00 SOLVE T*X=B, T LOWER TRIANGULAR,
C 01 SOLVE T*X=B, T UPPER TRIANGULAR,
C 10 SOLVE TRANS(T)*X=B, T LOWER TRIANGULAR,
C 11 SOLVE TRANS(T)*X=B, T UPPER TRIANGULAR.
C
C ON RETURN
C
C B B CONTAINS THE SOLUTION, IF INFO .EQ. 0.
C OTHERWISE B IS UNALTERED.
C
C INFO INTEGER
C INFO CONTAINS ZERO IF THE SYSTEM IS NONSINGULAR.
C OTHERWISE INFO CONTAINS THE INDEX OF
C THE FIRST ZERO DIAGONAL ELEMENT OF T.
C
C LINPACK. THIS VERSION DATED 08/14/78 .
C G. W. STEWART, UNIVERSITY OF MARYLAND, ARGONNE NATIONAL LAB.
C
C SUBROUTINES AND FUNCTIONS
C
C BLAS SAXPY,SDOT
C FORTRAN MOD
C