cospi¶

Computes the cosine of vector elements multiplied by π.

Syntax

Buffer API:

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

USM API:

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

cospi supports the following precisions.:

T
`float`
`double`

Description

The cospi(a) function computes the cosine of vector elements multiplied by π. For an argument a, the function computes cos(π*a).

Argument	Result	Error Code
+0	+1
-0	+1
`n` + 0.5, for any integer `n` where `n` + 0.5 is representable	+0
+∞	QNAN	`status::errdom`
-∞	QNAN	`status::errdom`
QNAN	QNAN
SNAN	QNAN

If arguments abs(a_i) ≤ 2²² for single precision or abs(a_i ) ≤ 2⁵¹ for double precision, they belong to the fast computational path: arguments for which VM provides the best possible performance. Avoid arguments which do not belong to the fast computational path in VM High Accuracy (HA) or Low Accuracy (LA) functions. For arguments which do not belong to the fast computational path you can use VM Enhanced Performance (EP) functions, which are fast on the entire function domain. However, these functions provide lower accuracy.

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 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 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 cospi can be found in the oneMKL installation directory, under:

examples/sycl/vml/vcospi.cpp

Parent topic: Trigonometric Functions