powr¶

Computes a to the power b for elements of two vectors, where the elements of vector argument a are all non-negative.

Syntax

Buffer API:

void powr(queue &exec_queue, int64_t n, buffer<T, 1> &a, buffer<T, 1> &b, buffer<T, 1> &y, uint64_t mode = mode::not_defined, error_handler<T> errhandler = {})¶

USM API:

event powr(queue &exec_queue, int64_t n, T *a, T *b, T *y, vector_class<event> *depends, uint64_t mode = mode::not_defined, error_handler<T> errhandler = {})¶

powr supports the following precisions.

T
`float`
`double`

Description

The powr(a,b) function raises each element of vector a by the corresponding element of vector b. The elements of a are all nonnegative (a_i≥ 0).

Data Type	Threshold Limitations on Input Parameters
single precision	`a`_i < (FLT_MAX)^1/``b`i`
double precision	`a`_i < (DBL_MAX)^1/``b`i`

Special values and VM Error Status treatment for v?Powr function are the same as for pow, unless otherwise indicated in this table:

Argument 1	Argument 2	Result	Error Code
`a` < 0	any value `b`	NAN	`status::errdom`
0 < `a` < ∞	±0	1
±0	-∞ < `b` < 0	+∞
±0	-∞	+∞
±0	`b` > 0	+0
1	-∞ < `b` < ∞	1
±0	±0	NAN
+∞	±0	NAN
1	+∞	NAN
`a`≥ 0	NAN	NAN
NAN	any value `b`	NAN
0 < `a` <1	-∞	+∞
`a` > 1	-∞	+0
0 ≤`a` < 1	+∞	+0
`a` > 1	+∞	+∞
+∞	`b` < +0	+0
+∞	`b` > +0	+∞
QNAN	QNAN	QNAN	`status::errdom`
QNAN	SNAN	QNAN	`status::errdom`
SNAN	QNAN	QNAN	`status::errdom`
SNAN	SNAN	QNAN	`status::errdom`

Input Parameters

Buffer API:

exec_queue: The queue where the routine should be executed.
n: Specifies the number of elements to be calculated.
a: The buffer a containing 1st input vector of size n.
b: The buffer b containing 2nd input vector of size n.
mode: Overrides the global VM mode setting for this function call. See set_mode function for possible values and their description. This is an optional parameter. The default value is mode::not_defined.
errhandler: Sets local error handling mode for this function call. See the create_error_handler function for arguments and their descriptions. This is an optional parameter. The local error handler is disabled by default.

USM API:

exec_queue: The queue where the routine should be executed.
n: Specifies the number of elements to be calculated.
a: Pointer a to the 1st input vector of size n.
b: Pointer b to the 2nd input vector of size n.
depends: Vector of dependent events (to wait for input data to be ready).
mode: Overrides the global VM mode setting for this function call. See the set_mode function for possible values and their description. This is an optional parameter. The default value is mode::not_defined.
errhandler: Sets local error handling mode for this function call. See the create_error_handler function for arguments and their descriptions. This is an optional parameter. The local error handler is disabled by default.

Output Parameters

Buffer API:

y: The buffer y containing the output vector of size n.

USM API:

y: Pointer y to the output vector of size n.
return value (event): Function end event.

Example

An example of how to use powr can be found in the oneMKL installation directory, under:

examples/sycl/vml/vpowr.cpp

Parent topic: Power and Root Functions