Developer Reference for Intel® oneAPI Math Kernel Library - C

Developer Reference

  • 0.9
  • 09/09/2020
  • Public Content
Contents

?lantr

Returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a trapezoidal or triangular matrix.

Syntax

float
LAPACKE_slantr
(
char
*
norm
,
char
*
uplo
,
char
*
diag
,
lapack_int
*
m
,
lapack_int
*
n
,
const
float
*
a
,
lapack_int
*
lda
,
float
*
work
);
double
LAPACKE_dlantr
(
char
*
norm
,
char
*
uplo
,
char
*
diag
,
lapack_int
*
m
,
lapack_int
*
n
,
const
double
*
a
,
lapack_int
*
lda
,
double
*
work
);
float
LAPACKE_clantr
(
char
*
norm
,
char
*
uplo
,
char
*
diag
,
lapack_int
*
m
,
lapack_int
*
n
,
const
lapack_complex_float
*
a
,
lapack_int
*
lda
,
float
*
work
);
double
LAPACKE_zlantr
(
char
*
norm
,
char
*
uplo
,
char
*
diag
,
lapack_int
*
m
,
lapack_int
*
n
,
const
lapack_complex_double
*
a
,
lapack_int
*
lda
,
double
*
work
);
Include Files
  • mkl.h
Description
The function
?lantr
 returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a trapezoidal or triangular matrix
A
.
Input Parameters
A
<datatype>
 placeholder, if present, is used for the C interface data types in the C interface section above. See C Interface Conventions for the C interface principal conventions and type definitions.
norm
Specifies the value to be returned by the routine:
=
'M'
 or
'm':
val
 =
max
(
abs
(
A
ij
))
, largest absolute value of the matrix
A
.
=
'1'
 or
'O'
 or
'o':
val
 =
norm1
(
A
)
, 1-norm of the matrix
A
 (maximum column sum),
=
'I'
 or
'i':
val
 =
normI
(
A
)
, infinity norm of the matrix
A
 (maximum row sum),
=
'F'
,
'f'
,
'E'
 or
'e':
val
 =
normF
(
A
)
, Frobenius norm of the matrix
A
 (square root of sum of squares).
uplo
Specifies whether the matrix
A
 is upper or lower trapezoidal.
=
'U'
: Upper trapezoidal
=
'L'
: Lower trapezoidal.
Note that
A
 is triangular instead of trapezoidal if
m
 =
n
.
diag
Specifies whether or not the matrix
A
 has unit diagonal.
=
'N'
: Non-unit diagonal
=
'U'
: Unit diagonal.
m
The number of rows of the matrix
A
.
m
≥
 0
, and if
uplo
 =
'U'
,
m
 ≤
n
.
When
m
 = 0
,
?lantr
 is set to zero.
n
The number of columns of the matrix
A
.
n
≥
 0
, and if
uplo
 =
'L'
,
n
 ≤
m
.
When
n
 = 0
,
?lantr
 is set to zero.
a
Array, size at least
max(1,
lda
*
n
)
 for column major and
max(1,
lda
*
m
)
 for row major layout.
The trapezoidal matrix
A
 (
A
 is triangular if
m
 =
n
)
.
If
uplo
 =
'U'
, the leading
m
-by-
n
 upper trapezoidal part of the array
a
 contains the upper trapezoidal matrix, and the strictly lower triangular part of
A
 is not referenced.
If
uplo
 =
'L'
, the leading
m
-by-
n
 lower trapezoidal part of the array
a
 contains the lower trapezoidal matrix, and the strictly upper triangular part of
A
 is not referenced. Note that when
diag
 =
'U'
, the diagonal elements of
A
 are not referenced and are assumed to be one.
lda
The leading dimension of the array
a
.
lda
≥
 max(
m
,1)
for column major layout and
≥
max(1,
n
) for row major layout
.

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