Developer Reference

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

p?amax

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

Syntax

call psamax
(
n
,
amax
,
indx
,
x
,
ix
,
jx
,
descx
,
incx
)
call pdamax
(
n
,
amax
,
indx
,
x
,
ix
,
jx
,
descx
,
incx
)
call pcamax
(
n
,
amax
,
indx
,
x
,
ix
,
jx
,
descx
,
incx
)
call pzamax
(
n
,
amax
,
indx
,
x
,
ix
,
jx
,
descx
,
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)
INTEGER
.
The length of distributed vector
sub(
x
)
,
n
0.
x
(local)
REAL
for
psamax
DOUBLE PRECISION
for
pdamax
COMPLEX
for
pcamax
DOUBLE COMPLEX
for
pzamax
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)
INTEGER
.
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)
INTEGER
array of dimension 9. The array descriptor of the distributed matrix
X
.
incx
(global)
INTEGER
.
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)
REAL
for
psamax
.
DOUBLE PRECISION
for
pdamax
.
COMPLEX
for
pcamax
.
DOUBLE COMPLEX
for
pzamax
.
Maximum absolute value (magnitude) of elements of the distributed vector only in its scope.
indx
(global)
INTEGER
.
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

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 manuf