SGESL(3F)SGESL(3F)NAMESGESL - SGESL solves the real system A * X = B or TRANS(A) * X = B
using the factors computed by SGECO or SGEFA.
SYNOPSYS
SUBROUTINE SGESL(A,LDA,N,IPVT,B,JOB)
DESCRIPTION
On Entry
A REAL(LDA, N)
the output from SGECO or SGEFA.
LDA INTEGER
the leading dimension of the array A .
N INTEGER
the order of the matrix A .
IPVT INTEGER(N)
the pivot vector from SGECO or SGEFA.
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 SGECO has set RCOND
.GT. 0.0 or SGEFA has set INFO .EQ. 0 . To compute INVERSE(A) * C
where C is a matrix with P columns
CALL SGECO(A,LDA,N,IPVT,RCOND,Z)
IF (RCOND is too small) GO TO ...
DO 10 J = 1, P
CALL SGESL(A,LDA,N,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
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