Developer Reference for Intel® oneAPI Math Kernel Library - C

Developer Reference

Contents

?tftri

Computes the inverse of a triangular matrix stored in the Rectangular Full Packed (RFP) format.

Syntax

lapack_int
LAPACKE_stftri
(
int
matrix_layout
,
char
transr
,
char
uplo
,
char
diag
,
lapack_int
n
,
float
*
a
);
lapack_int
LAPACKE_dtftri
(
int
matrix_layout
,
char
transr
,
char
uplo
,
char
diag
,
lapack_int
n
,
double
*
a
);
lapack_int
LAPACKE_ctftri
(
int
matrix_layout
,
char
transr
,
char
uplo
,
char
diag
,
lapack_int
n
,
lapack_complex_float
*
a
);
lapack_int
LAPACKE_ztftri
(
int
matrix_layout
,
char
transr
,
char
uplo
,
char
diag
,
lapack_int
n
,
lapack_complex_double
*
a
);
Include Files
  • mkl.h
Description
Computes the inverse of a triangular matrix
A
 stored 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
matrix_layout
Specifies whether matrix storage layout is row major (
LAPACK_ROW_MAJOR
) or column major (
LAPACK_COL_MAJOR
).
transr
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
Must be
'U'
 or
'L'
.
Indicates whether the upper or lower triangular part of RFP
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
.
diag
Must be
'N'
 or
'U'
.
If
diag
 =
'N'
, then
A
 is not a unit triangular matrix.
If
diag
 =
'U'
,
A
 is unit triangular: diagonal elements of
A
 are assumed to be 1 and not referenced in the array
a
.
n
The order of the matrix
A
;
n
≥
 0.
a
Array, size max(1,
n
*(
n
 + 1)/2). The array
a
 contains the matrix
A
 in the RFP format.
Output Parameters
a
The (triangular) inverse of the original matrix in the same storage format.
Return Values
This function returns a value
info
.
If
info
=0
, the execution is successful.
If
info
 =
-i
, parameter
i
 had an illegal value.
If
info
 =
i
,
A
i
,
i
 is exactly zero. The triangular matrix is singular and its inverse cannot be computed.

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.