ctpcon.f - Man Page
SRC/ctpcon.f
Synopsis
Functions/Subroutines
subroutine ctpcon (norm, uplo, diag, n, ap, rcond, work, rwork, info)
CTPCON
Function/Subroutine Documentation
subroutine ctpcon (character norm, character uplo, character diag, integer n, complex, dimension( * ) ap, real rcond, complex, dimension( * ) work, real, dimension( * ) rwork, integer info)
CTPCON
Purpose:
CTPCON estimates the reciprocal of the condition number of a packed triangular matrix A, in either the 1-norm or the infinity-norm. The norm of A is computed and an estimate is obtained for norm(inv(A)), then the reciprocal of the condition number is computed as RCOND = 1 / ( norm(A) * norm(inv(A)) ).
- Parameters
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.
UPLO
UPLO is CHARACTER*1 = 'U': A is upper triangular; = 'L': A is lower triangular.
DIAG
DIAG is CHARACTER*1 = 'N': A is non-unit triangular; = 'U': A is unit triangular.
N
N is INTEGER The order of the matrix A. N >= 0.
AP
AP is COMPLEX array, dimension (N*(N+1)/2) The upper or lower triangular matrix A, packed columnwise in a linear array. The j-th column of A is stored in the array AP as follows: if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j; if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n. If DIAG = 'U', the diagonal elements of A are not referenced and are assumed to be 1.
RCOND
RCOND is REAL The reciprocal of the condition number of the matrix A, computed as RCOND = 1/(norm(A) * norm(inv(A))).
WORK
WORK is COMPLEX array, dimension (2*N)
RWORK
RWORK is REAL array, dimension (N)
INFO
INFO is INTEGER = 0: successful exit < 0: if INFO = -i, the i-th argument had an illegal value
- Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 128 of file ctpcon.f.
Author
Generated automatically by Doxygen for LAPACK from the source code.
Referenced By
The man page ctpcon(3) is an alias of ctpcon.f(3).
Tue Nov 28 2023 12:08:41 Version 3.12.0 LAPACK