SGEFA - SGEFA factors a real matrix by Gaussian elimination.
SGEFA is usually called by SGECO, but it can be called directly with a
saving in time if RCOND is not needed. (Time for SGECO) = (1 +
9/N)*(Time for SGEFA) .
A REAL(LDA, N)
the matrix to be factored.
the leading dimension of the array A .
the order of the matrix A . On Return
A an upper triangular matrix and the multipliers
which were used to obtain it.
The factorization can be written A = L*U , where
L is a product of permutation and unit lower
triangular matrices and U is upper triangular.
an integer vector of pivot indices.
= 0 normal value.
= K if U(K,K) .EQ. 0.0 . This is not an error
condition for this subroutine, but it does
indicate that SGESL or SGEDI will divide by zero
if called. Use RCOND in SGECO for a reliable
indication of singularity. LINPACK. This version dated 08/14/78 .
Cleve Moler, University of New Mexico, Argonne National Lab. Subroutines
and Functions BLAS SAXPY,SSCAL,ISAMAX
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