Developer Reference

  • 2020.2
  • 07/15/2020
  • Public Content
Contents

?pftrf

Computes the Cholesky factorization of a symmetric (Hermitian) positive-definite matrix using the Rectangular Full Packed (RFP) format .

Syntax

call spftrf
(
transr
,
uplo
,
n
,
a
,
info
)
call dpftrf
(
transr
,
uplo
,
n
,
a
,
info
)
call cpftrf
(
transr
,
uplo
,
n
,
a
,
info
)
call zpftrf
(
transr
,
uplo
,
n
,
a
,
info
)
Include Files
  • mkl.fi
    ,
    lapack.f90
Description
The routine forms the Cholesky factorization of a symmetric positive-definite or, for complex data, a Hermitian positive-definite matrix
A
:
A
=
U
T
*U
for real data,
A
=
U
H
*U
for complex data
if
uplo
=
'U'
A
=
L*L
T
for real data,
A
=
L*L
H
for complex data
if
uplo
=
'L'
where
L
is a lower triangular matrix and
U
is upper triangular.
The matrix
A
is in the Rectangular Full Packed (RFP) format. For the description of the RFP format, see Matrix Storage Schemes .
This is the block version of the algorithm, calling Level 3 BLAS.
Input Parameters
transr
CHARACTER*1
.
Must be
'N'
,
'T'
(for real data) or
'C'
(for complex data).
If
transr
=
'N'
, the Normal
transr
of RFP
A
is stored.
If
transr
=
'T'
, the Transpose
transr
of RFP
A
is stored.
If
transr
=
'C'
, the Conjugate-Transpose
transr
of RFP
A
is stored.
uplo
CHARACTER*1
.
Must be
'U'
or
'L'
.
Indicates whether the upper or lower triangular part of
A
is stored:
If
uplo
=
'U'
, the array
a
stores the upper triangular part of the matrix
A
.
If
uplo
=
'L'
, the array
a
stores the lower triangular part of the matrix
A
.
n
INTEGER
.
The order of the matrix
A
;
n
0.
a
REAL
for
spftrf
DOUBLE PRECISION
for
dpftrf
COMPLEX
for
cpftrf
DOUBLE COMPLEX
for
zpftrf
.
Array, size
(
n
*(
n
+1)/2)
. The array
a
contains the matrix
A
in the RFP format.
Output Parameters
a