|
NAG[f07fwc] NAG[nag_zpotri] - Inverse of complex Hermitian positive-definite matrix, matrix already factorized by f07frc (nag_zpotrf)
|
|
Calling Sequence
f07fwc(uplo, a, 'n'=n, 'fail'=fail)
nag_zpotri(. . .)
Parameters
|
uplo - String;
|
|
|
Constraint: "Nag_Upper" or "Nag_Lower". .
|
|
|
a - Matrix(1..dim1, 1..dim2, datatype=complex[8], order=order);
|
|
|
Note: this array may be supplied in Fortran_order or C_order , as specified by order. All array parameters must use a consistent order.
|
|
|
'n'=n - integer; (optional)
|
|
|
Default value: the dimension of the array a.
|
|
On entry: , the order of the matrix .
|
|
Constraint: . .
|
|
|
'fail'=fail - table; (optional)
|
|
|
The NAG error argument, see the documentation for NagError.
|
|
|
|
Description
|
|
|
Purpose
|
|
nag_zpotri (f07fwc) computes the inverse of a complex Hermitian positive-definite matrix , where has been factorized by f07frc (nag_zpotrf).
|
|
Error Indicators and Warnings
|
|
"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"
Element of the diagonal of the Cholesky factor is zero. The Cholesky factor is singular, and the inverse of cannot be computed.
|
|
Further Comments
|
|
The total number of real floating-point operations is approximately .
The real analogue of this function is f07fjc (nag_dpotri).
|
|
|
Examples
|
|
>
|
uplo := "Nag_Lower":
n := 4:
a := Matrix([[1.797220075561143 +0*I , 0 +0*I , 0 +0*I , 0 +0*I ], [0.8401864749527325 +1.068316577423342*I , 1.316353439509685 +0*I , 0 +0*I , 0 +0*I ], [1.057188279741849 -0.467388502622712*I , -0.4701749470106329 +0.3130658155999466*I , 1.560392977137124 +0*I , 0 +0*I ], [0.233694251311356 -1.391037210186643*I , 0.08335250923944196 +0.03676071443037457*I , 0.9359617337923402 +0.9899692192815734*I , 0.6603332973655891 +0*I ]], datatype=complex[8], order='C_order'):
NAG:-f07fwc(uplo, a, 'n' = n):
|

|
|