Developer Reference

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

p?max1

Finds the index of the element whose real part has maximum absolute value (similar to the Level 1 PBLAS
p?amax
, but using the absolute value to the real part).

Syntax

void
pcmax1
(
MKL_INT
*n
,
MKL_Complex8
*amax
,
MKL_INT
*indx
,
MKL_Complex8
*x
,
MKL_INT
*ix
,
MKL_INT
*jx
,
MKL_INT
*descx
,
MKL_INT
*incx
);
void
pzmax1
(
MKL_INT
*n
,
MKL_Complex16
*amax
,
MKL_INT
*indx
,
MKL_Complex16
*x
,
MKL_INT
*ix
,
MKL_INT
*jx
,
MKL_INT
*descx
,
MKL_INT
*incx
);
Include Files
  • mkl_scalapack.h
Description
The
p?max1
function
computes the global index of the maximum element in absolute value of a distributed vector sub(
X
). The global index is returned in
indx
and the value is returned in
amax
, where sub(
X
) denotes
X
(
ix
:
ix
+
n
-1,
jx
)
if
incx
= 1
,
X
(
ix
,
jx
:
jx
+
n
-1)
if
incx
=
m_x
.
Input Parameters
n
(global). The number of components of the distributed vector sub(
X
).
n
0.
x
(local)
Pointer into the local memory to an array of size
lld_x
*
LOCc
(
jx
+
n
-1)
. On entry this array contains the local pieces of the distributed vector sub(
X
).
ix
(global) The row index in the global matrix
X
indicating the first row of sub(
X
).
jx
(global) The column index in the global matrix
X
indicating the first column of sub(
X
).
descx
(global and local) Array of size
dlen_
. The array descriptor for the distributed matrix
X
.
incx
(global).The global increment for the elements of
X
. Only two values of
incx
are supported in this version, namely 1 and
m_x
.
incx
must not be zero.
Output Parameters
amax
(global output).The absolute value of the largest entry of the distributed vector sub(
X
) only in the scope of sub(
X
).
indx
(global output).The global index of the element of the distributed vector sub(
X
) whose real part has maximum absolute value.

Product and Performance Information

1

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