cgscon.c File Reference

Estimates reciprocal of the condition number of a general matrix. More...

`#include <math.h>`
`#include "slu_cdefs.h"`
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## Functions

void | cgscon (char *norm, SuperMatrix *L, SuperMatrix *U, float anorm, float *rcond, SuperLUStat_t *stat, int *info)

## Detailed Description

Copyright (c) 2003, The Regents of the University of California, through Lawrence Berkeley National Laboratory (subject to receipt of any required approvals from U.S. Dept. of Energy)

All rights reserved.

The source code is distributed under BSD license, see the file License.txt at the top-level directory.

    -- SuperLU routine (version 5.0) --
    Univ. of California Berkeley, Xerox Palo Alto Research Center,
    and Lawrence Berkeley National Lab.
    July 25, 2015

    Modified from lapack routines CGECON.

## Function Documentation

void cgscon | ( | char * | norm,
|  | SuperMatrix * | L,
|  | SuperMatrix * | U,
|  | float | anorm,
|  | float * | rcond,
|  | SuperLUStat_t * | stat,
|  | int * | info
| ) |  |

#

    Purpose

      CGSCON estimates the reciprocal of the condition number of a general
      real matrix A, in either the 1-norm or the infinity-norm, using
      the LU factorization computed by CGETRF.   *

      An estimate is obtained for norm(inv(A)), and the reciprocal of the
      condition number is computed as
         RCOND = 1 / ( norm(A) * norm(inv(A)) ).

      See supermatrix.h for the definition of 'SuperMatrix' structure.

#

    Arguments

       NORM    (input) char*
               Specifies whether the 1-norm condition number or the
               infinity-norm condition number is required:
               = '1' or 'O':  1-norm;
               = 'I':         Infinity-norm.

       L       (input) SuperMatrix*
               The factor L from the factorization Pr*A*Pc=L*U as computed by
               cgstrf(). Use compressed row subscripts storage for supernodes,
               i.e., L has types: Stype = SLU_SC, Dtype = SLU_C, Mtype = SLU_TRLU.

       U       (input) SuperMatrix*
               The factor U from the factorization Pr*A*Pc=L*U as computed by
               cgstrf(). Use column-wise storage scheme, i.e., U has types:
               Stype = SLU_NC, Dtype = SLU_C, Mtype = SLU_TRU.

       ANORM   (input) float
               If NORM = '1' or 'O', the 1-norm of the original matrix A.
               If NORM = 'I', the infinity-norm of the original matrix A.

       RCOND   (output) float*
              The reciprocal of the condition number of the matrix A,
              computed as RCOND = 1/(norm(A) * norm(inv(A))).

       INFO    (output) int*
              = 0:  successful exit
              < 0:  if INFO = -i, the i-th argument had an illegal value

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