Developer Reference for Intel® oneAPI Math Kernel Library - C

Developer Reference

  • 2021.1
  • 12/04/2020
  • Public Content
Contents

p?amax

Computes the global index of the element of a distributed vector with maximum absolute value.

Syntax

void psamax
(
const MKL_INT
*n
,
float
*amax
,
MKL_INT
*indx
,
const float
*x
,
const MKL_INT
*ix
,
const MKL_INT
*jx
,
const MKL_INT
*descx
,
const MKL_INT
*incx
);
void pdamax
(
const MKL_INT
*n
,
double
*amax
,
MKL_INT
*indx
,
const double
*x
,
const MKL_INT
*ix
,
const MKL_INT
*jx
,
const MKL_INT
*descx
,
const MKL_INT
*incx
);
void pcamax
(
const MKL_INT
*n
,
MKL_Complex8
*amax
,
MKL_INT
*indx
,
const MKL_Complex8
*x
,
const MKL_INT
*ix
,
const MKL_INT
*jx
,
const MKL_INT
*descx
,
const MKL_INT
*incx
);
void pzamax
(
const MKL_INT
*n
,
MKL_Complex16
*amax
,
MKL_INT
*indx
,
const MKL_Complex16
*x
,
const MKL_INT
*ix
,
const MKL_INT
*jx
,
const MKL_INT
*descx
,
const MKL_INT
*incx
);
Include Files
  • mkl_pblas.h
Description
The functions
p?amax
 compute global index of the maximum element in absolute value of a distributed vector
sub(
x
)
,
where
sub(
x
)
 denotes
X
(
ix
,
jx
:
jx
+
n
-1)
 if
incx
=
m_x
, and
X
(
ix
:
ix
+
n
-1,
jx
)
 if
incx
= 1
.
Input Parameters
n
(global) The length of distributed vector
sub(
x
)
,
n
≥
0.
x
(local)
Array, size
(
jx
-1)*
m_x
 +
ix
+(
n
-1)*abs(
incx
))
.
This array contains the entries of the distributed vector
sub(
x
)
.
ix
,
jx
(global) The row and column indices in the distributed matrix
X
 indicating the first row and the first column of the submatrix
sub(
X
)
, respectively.
descx
(global and local) array of dimension 9. The array descriptor of the distributed matrix
X
.
incx
(global) Specifies the increment for the elements of
sub(
x
)
. Only two values are supported, namely 1 and
m_x
.
incx
 must not be zero.
Output Parameters
amax
(global).
Maximum absolute value (magnitude) of elements of the distributed vector only in its scope.
indx
(global) The global index of the maximum element in absolute value of the distributed vector
sub(
x
)
 only in its scope.

Product and Performance Information

1

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