GNU/Linux man pages
Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :
GNU/Linux |
CentOS 4.8 |
i386 |
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cspcon(l) |
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CSPCON - estimate the reciprocal of the condition number (in the 1-norm) of a complex symmetric packed matrix A using the factorization A = U*D*U**T or A = L*D*L**T computed by CSPTRF
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SUBROUTINE CSPCON( |
UPLO, N, AP, IPIV, ANORM, RCOND, WORK, INFO ) | ||
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CHARACTER |
UPLO | ||
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INTEGER |
INFO, N | ||
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REAL |
ANORM, RCOND | ||
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INTEGER |
IPIV( * ) | ||
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COMPLEX |
AP( * ), WORK( * ) |
CSPCON estimates the reciprocal of the condition number (in the 1-norm) of a complex symmetric packed matrix A using the factorization A = U*D*U**T or A = L*D*L**T computed by CSPTRF. An estimate is obtained for norm(inv(A)), and the reciprocal of the condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))).
UPLO (input) CHARACTER*1
Specifies whether the details
of the factorization are stored as an upper or lower
triangular matrix. = ’U’: Upper triangular, form
is A = U*D*U**T;
= ’L’: Lower triangular, form is A =
L*D*L**T.
N (input) INTEGER
The order of the matrix A. N >= 0.
AP (input) COMPLEX array, dimension (N*(N+1)/2)
The block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by CSPTRF, stored as a packed triangular matrix.
IPIV (input) INTEGER array, dimension (N)
Details of the interchanges and the block structure of D as determined by CSPTRF.
ANORM (input) REAL
The 1-norm of the original matrix A.
RCOND (output) REAL
The reciprocal of the condition number of the matrix A, computed as RCOND = 1/(ANORM * AINVNM), where AINVNM is an estimate of the 1-norm of inv(A) computed in this routine.
WORK (workspace) COMPLEX array,
dimension (2*N)
INFO (output) INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal
value
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cspcon(l) | |