Contents

# ?tftri

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

## Syntax

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
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.