Developer Reference

Contents

cblas_i?amax

Finds the index of the element with maximum absolute value.

Syntax

CBLAS_INDEX
cblas_isamax
(
const
MKL_INT
n
,
const
float
*x
,
const
MKL_INT
incx
);
CBLAS_INDEX
cblas_idamax
(
const
MKL_INT
n
,
const
double
*x
,
const
MKL_INT
incx
);
CBLAS_INDEX
cblas_icamax
(
const
MKL_INT
n
,
const
void
*x
,
const
MKL_INT
incx
);
CBLAS_INDEX
cblas_izamax
(
const
MKL_INT
n
,
const
void
*x
,
const
MKL_INT
incx
);
Include Files
  • mkl.h
Description
Given a vector
x
, the
i?amax
functions return the position of the vector element
x
[
i
] that has the largest absolute value for real flavors, or the largest sum
|Re(
x
[
i
])|+|Im(
x
[
i
])|
for complex flavors.
If either
n
or
incx
are not positive, the routine returns
0
.
If more than one vector element is found with the same largest absolute value, the index of the first one encountered is returned.
If the vector contains
NaN
values, then the routine returns the index of the first
NaN
.
Input Parameters
n
Specifies the number of elements in vector
x
.
x
Array, size at least
(1+(
n
-1)*abs(
incx
))
.
incx
Specifies the increment for the elements of
x
.
Return Values
Returns the position of vector element that has the largest absolute value such that
x
[
index
-1] has the largest absolute value. The index returned is zero-based.

Product and Performance Information

1

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