sgeco
sgeco - (obsolete) compute the LU factorization and estimate the condition number of a
general matrix A. If the condition number is not needed then SGEFA is slightly faster. It is typical to follow a call
to SGECO with a call to SGESL to solve Ax = b or to SGEDI to compute the determinant and inverse of A.
SUBROUTINE SGECO( A, LDA, N, IPIVOT, RCOND, WORK)
INTEGER LDA, N
INTEGER IPIVOT(*)
REAL RCOND
REAL A(LDA,*), WORK(*)
SUBROUTINE SGECO_64( A, LDA, N, IPIVOT, RCOND, WORK)
INTEGER*8 LDA, N
INTEGER*8 IPIVOT(*)
REAL RCOND
REAL A(LDA,*), WORK(*)
#include <sunperf.h>
void sgeco(float *a, int lda, int n, int *ipivot, float *rcond);
void sgeco_64(float *a, long lda, long n, long *ipivot, float *rcond);
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* A (input/output)
-
On entry, the matrix A.
On exit, an LU factorization of A.
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* LDA (input)
-
Leading dimension of the array A as specified in a dimension or
type statement. LDA >= max(1,N).
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* N (input)
-
Order of the matrix A. N >= 0.
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* IPIVOT (output)
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On exit, a vector of pivot indices.
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* RCOND (output)
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On exit, an estimate of the reciprocal condition number of A.
0.0 <= RCOND <= 1.0. As the value of
RCOND gets smaller, operations with A such as solving Ax = b may become
less stable. If RCOND
satisfies RCOND + 1.0 = 1.0 then A may be singular to working precision.
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* WORK (workspace)
-
Scratch array with a dimension of N.