dtpcon.f man page
subroutine dtpcon (NORM, UPLO, DIAG, N, AP, RCOND, WORK, IWORK, INFO)
subroutine dtpcon (character NORM, character UPLO, character DIAG, integer N, double precision, dimension( * ) AP, double precision RCOND, double precision, dimension( * ) WORK, integer, dimension( * ) IWORK, integer INFO)
DTPCON 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)) ).
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 is CHARACTER*1 = 'U': A is upper triangular; = 'L': A is lower triangular.
DIAG is CHARACTER*1 = 'N': A is non-unit triangular; = 'U': A is unit triangular.
N is INTEGER The order of the matrix A. N >= 0.
AP is DOUBLE PRECISION 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 is DOUBLE PRECISION The reciprocal of the condition number of the matrix A, computed as RCOND = 1/(norm(A) * norm(inv(A))).
WORK is DOUBLE PRECISION array, dimension (3*N)
IWORK is INTEGER array, dimension (N)
INFO is INTEGER = 0: successful exit < 0: if INFO = -i, the i-th argument had an illegal value
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
Definition at line 132 of file dtpcon.f.
Generated automatically by Doxygen for LAPACK from the source code.
The man page dtpcon(3) is an alias of dtpcon.f(3).