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LAPACK
3.7.0
LAPACK: Linear Algebra PACKage
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subroutine cgecon | ( | character | NORM, |
integer | N, | ||
complex, dimension( lda, * ) | A, | ||
integer | LDA, | ||
real | ANORM, | ||
real | RCOND, | ||
complex, dimension( * ) | WORK, | ||
real, dimension( * ) | RWORK, | ||
integer | INFO | ||
) |
CGECON
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CGECON estimates the reciprocal of the condition number of a general complex 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)) ).
[in] | NORM | NORM is CHARACTER*1 Specifies whether the 1-norm condition number or the infinity-norm condition number is required: = '1' or 'O': 1-norm; = 'I': Infinity-norm. |
[in] | N | N is INTEGER The order of the matrix A. N >= 0. |
[in] | A | A is COMPLEX array, dimension (LDA,N) The factors L and U from the factorization A = P*L*U as computed by CGETRF. |
[in] | LDA | LDA is INTEGER The leading dimension of the array A. LDA >= max(1,N). |
[in] | ANORM | ANORM is REAL If NORM = '1' or 'O', the 1-norm of the original matrix A. If NORM = 'I', the infinity-norm of the original matrix A. |
[out] | RCOND | RCOND is REAL The reciprocal of the condition number of the matrix A, computed as RCOND = 1/(norm(A) * norm(inv(A))). |
[out] | WORK | WORK is COMPLEX array, dimension (2*N) |
[out] | RWORK | RWORK is REAL array, dimension (2*N) |
[out] | INFO | INFO is INTEGER = 0: successful exit < 0: if INFO = -i, the i-th argument had an illegal value |
Definition at line 126 of file cgecon.f.