SGBSL(3F)SGBSL(3F)NAMESGBSL - SGBSL solves the real band system A * X = B or TRANS(A) * X =
B using the factors computed by SBGCO or SGBFA.
SYNOPSYS
SUBROUTINE SGBSL(ABD,LDA,N,ML,MU,IPVT,B,JOB)
DESCRIPTION
On Entry
ABD REAL(LDA, N)
the output from SBGCO or SGBFA.
LDA INTEGER
the leading dimension of the array ABD .
N INTEGER
the order of the original matrix.
ML INTEGER
number of diagonals below the main diagonal.
MU INTEGER
number of diagonals above the main diagonal.
IPVT INTEGER(N)
the pivot vector from SBGCO or SGBFA.
B REAL(N)
the right hand side vector.
JOB INTEGER
= 0 to solve A*X = B ,
= nonzero to solve TRANS(A)*X = B , where
TRANS(A) is the transpose. On Return
B the solution vector X . Error Condition
A division by zero will occur if the input factor contains a zero on the
diagonal. Technically, this indicates singularity, but it is often
caused by improper arguments or improper setting of LDA . It will not
occur if the subroutines are called correctly and if SBGCO has set RCOND
.GT. 0.0 or SGBFA has set INFO .EQ. 0 . To compute INVERSE(A) * C
where C is a matrix with P columns
CALL SBGCO(ABD,LDA,N,ML,MU,IPVT,RCOND,Z)
If (RCOND is too small) GO TO ...
DO 10 J = 1, P
CALL SGBSL(ABD,LDA,N,ML,MU,IPVT,C(1,J),0) 10 CONTINUE LINPACK. This
version dated 08/14/78 . Cleve Moler, University of New Mexico, Argonne
National Lab. Subroutines and Functions BLAS SAXPY,SDOT Fortran MIN0
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