Developer Reference

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

?trti2

Computes the inverse of a triangular matrix (unblocked algorithm).

Syntax

call strti2
(
uplo
,
diag
,
n
,
a
,
lda
,
info
)
call dtrti2
(
uplo
,
diag
,
n
,
a
,
lda
,
info
)
call ctrti2
(
uplo
,
diag
,
n
,
a
,
lda
,
info
)
call ztrti2
(
uplo
,
diag
,
n
,
a
,
lda
,
info
)
Include Files
  • mkl.fi
Description
The routine
?trti2
computes the inverse of a real/complex upper or lower triangular matrix.
This is the Level 2 BLAS version of the algorithm.
Input Parameters
uplo
CHARACTER*1
.
Specifies whether the matrix
A
is upper or lower triangular.
=
'U'
: upper triangular
=
'L'
: lower triangular
diag
CHARACTER*1
.
Specifies whether or not the matrix
A
is unit triangular.
=
'N'
: non-unit triangular
=
'N'
: non-unit triangular
n
INTEGER
. The order of the matrix
A
.
n
0
.
a
REAL
for
strti2
DOUBLE PRECISION
for
dtrti2
COMPLEX
for
ctrti2
DOUBLE COMPLEX
for
ztrti2
.
Array,
DIMENSION
(
lda
,
n
).
On entry, the triangular matrix
A
.
If
uplo
=
'U'
, the leading
n
-by-
n
upper triangular part of the array
a
contains the upper triangular matrix, and the strictly lower triangular part of
a
is not referenced.
If
uplo
=
'L'
, the leading
n
-by-
n
lower triangular part of the array
a
contains the lower triangular matrix, and the strictly upper triangular part of
a
is not referenced.
If
diag
=
'U'
, the diagonal elements of
a
are also not referenced and are assumed to be 1.
lda
INTEGER
. The leading dimension of the array
a
.
lda
max(1,
n
)
.
Output Parameters
a
On exit, the (triangular) inverse of the original matrix, in the same storage format.
info
INTEGER
.
= 0
: successful exit
< 0
: if
info
= -
k
, the
k
-th argument had an illegal value

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804