LAPACK
3.6.1
LAPACK: Linear Algebra PACKage
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real function sla_gercond | ( | character | TRANS, |
integer | N, | ||
real, dimension( lda, * ) | A, | ||
integer | LDA, | ||
real, dimension( ldaf, * ) | AF, | ||
integer | LDAF, | ||
integer, dimension( * ) | IPIV, | ||
integer | CMODE, | ||
real, dimension( * ) | C, | ||
integer | INFO, | ||
real, dimension( * ) | WORK, | ||
integer, dimension( * ) | IWORK | ||
) |
SLA_GERCOND estimates the Skeel condition number for a general matrix.
Download SLA_GERCOND + dependencies [TGZ] [ZIP] [TXT]
SLA_GERCOND estimates the Skeel condition number of op(A) * op2(C) where op2 is determined by CMODE as follows CMODE = 1 op2(C) = C CMODE = 0 op2(C) = I CMODE = -1 op2(C) = inv(C) The Skeel condition number cond(A) = norminf( |inv(A)||A| ) is computed by computing scaling factors R such that diag(R)*A*op2(C) is row equilibrated and computing the standard infinity-norm condition number.
[in] | TRANS | TRANS is CHARACTER*1 Specifies the form of the system of equations: = 'N': A * X = B (No transpose) = 'T': A**T * X = B (Transpose) = 'C': A**H * X = B (Conjugate Transpose = Transpose) |
[in] | N | N is INTEGER The number of linear equations, i.e., the order of the matrix A. N >= 0. |
[in] | A | A is REAL array, dimension (LDA,N) On entry, the N-by-N matrix A. |
[in] | LDA | LDA is INTEGER The leading dimension of the array A. LDA >= max(1,N). |
[in] | AF | AF is REAL array, dimension (LDAF,N) The factors L and U from the factorization A = P*L*U as computed by SGETRF. |
[in] | LDAF | LDAF is INTEGER The leading dimension of the array AF. LDAF >= max(1,N). |
[in] | IPIV | IPIV is INTEGER array, dimension (N) The pivot indices from the factorization A = P*L*U as computed by SGETRF; row i of the matrix was interchanged with row IPIV(i). |
[in] | CMODE | CMODE is INTEGER Determines op2(C) in the formula op(A) * op2(C) as follows: CMODE = 1 op2(C) = C CMODE = 0 op2(C) = I CMODE = -1 op2(C) = inv(C) |
[in] | C | C is REAL array, dimension (N) The vector C in the formula op(A) * op2(C). |
[out] | INFO | INFO is INTEGER = 0: Successful exit. i > 0: The ith argument is invalid. |
[in] | WORK | WORK is REAL array, dimension (3*N). Workspace. |
[in] | IWORK | IWORK is INTEGER array, dimension (N). Workspace.2 |
Definition at line 152 of file sla_gercond.f.