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NAG[f07pwc] NAG[nag_zhptri] - Inverse of complex Hermitian indefinite matrix, matrix already factorized by f07prc (nag_zhptrf), packed storage
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Calling Sequence
f07pwc(uplo, n, ap, ipiv, 'fail'=fail)
nag_zhptri(. . .)
Parameters
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uplo - String;
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On entry: indicates how has been factorized.
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Constraint: "Nag_Upper" or "Nag_Lower". .
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n - integer;
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On entry: , the order of the matrix .
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Constraint: . .
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ap - Vector(1..dim, datatype=complex[8]);
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Note: the dimension, dim, of the array ap must be at least .
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On entry: details of the factorization of stored in packed form, as returned by f07prc (nag_zhptrf).
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ipiv - Vector(1..dim, datatype=integer[kernelopts('wordsize')/8]);
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Note: the dimension, dim, of the array ipiv must be at least .
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On entry: details of the interchanges and the block structure of , as returned by f07prc (nag_zhptrf).
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'fail'=fail - table; (optional)
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The NAG error argument, see the documentation for NagError.
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Description
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Purpose
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nag_zhptri (f07pwc) computes the inverse of a complex Hermitian indefinite matrix , where has been factorized by f07prc (nag_zhptrf), using packed storage.
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Error Indicators and Warnings
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"NE_ALLOC_FAIL"
Dynamic memory allocation failed.
"NE_BAD_PARAM"
On entry, argument had an illegal value.
"NE_INT"
On entry, . Constraint: .
"NE_INTERNAL_ERROR"
An internal error has occurred in this function. Check the function call and any array sizes. If the call is correct then please consult NAG for assistance.
"NE_SINGULAR"
The block diagonal matrix is exactly singular.
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Further Comments
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The total number of real floating-point operations is approximately .
The real analogue of this function is f07pjc (nag_dsptri).
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Examples
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>
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uplo := "Nag_Lower":
n := 4:
ap := Vector([-4.981630459440283 +0*I, 0.210214907090655 +0.1106935130516159*I, -7.724450141995383 +0*I, 0.3100287981271241 -0.04333020743962702*I, -0.1518120207240102 -0.3742958425613706*I, -1.36 +0*I, 0.5637050486508776 -0.2850349501519716*I, 0.339658279960361 -0.03031451811355639*I, 3.91 -1.5*I, -1.84 +0*I], datatype=complex[8], order='C_order'):
ipiv := Vector([1, 2, -1, -1], datatype=integer[kernelopts('wordsize')/8]):
NAG:-f07pwc(uplo, n, ap, ipiv):
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