ctrco
ctrco - (obsolete) estimate the condition number of a triangular matrix A. It is typical to
follow a call to xTRCO with a call to xTRSL to solve Ax = b or to xTRDI to compute the determinant and inverse
of A.
SUBROUTINE CTRCO( A, LDA, N, RCOND, WORK, JOB)
COMPLEX A(LDA,*), WORK(*)
INTEGER LDA, N, JOB
REAL RCOND
SUBROUTINE CTRCO_64( A, LDA, N, RCOND, WORK, JOB)
COMPLEX A(LDA,*), WORK(*)
INTEGER*8 LDA, N, JOB
REAL RCOND
#include <sunperf.h>
void ctrco(complex *a, int lda, int n, float *rcond, int job);
void ctrco_64(complex *a, long lda, long n, float *rcond, long job);
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* A (input/output)
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Matrix 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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* RCOND (output)
-
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.
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* JOB (input)
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If JOB = 0, then A is lower triangular; otherwise A is upper
triangular.