logb

Computes the exponents of the elements of input vector a.

Syntax

Buffer API:

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

logb supports the following precisions.

T
float
double

Description

The logb(a) function computes the exponents of the elements of the input vector a. For each element a_i of vector a, this is the integral part of log₂|a_i|. The returned value is exact and is independent of the current rounding direction mode.

Argument	Result	VM Error Status
+0	+∞	status::errdom
-0	-∞	status::errdom
-∞	+∞
+∞	+∞
QNAN	QNAN
SNAN	QNAN

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 1st 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 logb can be found in the oneMKL installation directory, under:

examples/sycl/vml/vlogb.cpp

Parent topic: Exponential and Logarithmic Functions