log2

Intel® oneAPI Math Kernel Library (oneMKL) - Data Parallel C++ Developer Reference

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ID 772045

Date 12/16/2022

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log2

Computes the element-wise base-2 logarithm of vector elements.

Description
API
Examples

Description

The log2(a) function computes the base 2 logarithm of vector elements.

Argument	Result	Error Code
+1	+0
`a` < +0	QNAN	`status::errdom`
+0	-	`status::sing`
-0	-	`status::sing`
-	QNAN	`status::errdom`
+	+
QNAN	QNAN
SNAN	QNAN

API

Syntax

Buffer API

namespace oneapi::mkl::vm {

sycl::event log2(sycl::queue & exec_queue,
      std::int64_t n,
      sycl::buffer<T> & a,
      sycl::buffer<T> & y,
      oneapi::mkl::vm::mode mode = oneapi::mkl::vm::mode::not_defined,
      oneapi::mkl::vm::error_handler<T> errhandler = {});

}

namespace oneapi::mkl::vm {

sycl::event log2(sycl::queue & exec_queue,
      sycl::buffer<T> & a,
      oneapi::mkl::slice sa,
      sycl::buffer<T> & y,
      oneapi::mkl::slice sy,
      oneapi::mkl::vm::mode mode = oneapi::mkl::vm::mode::not_defined,
      oneapi::mkl::vm::error_handler<T> errhandler = {});

}

USM API

namespace oneapi::mkl::vm {

sycl::event log2(sycl::queue & exec_queue,
      std::int64_t n,
      T const * a,
      T * y,
      std::vector<sycl::event> const & depends = {},
      oneapi::mkl::vm::mode mode = oneapi::mkl::vm::mode::not_defined,
      oneapi::mkl::vm::error_handler<T> errhandler = {});

}

namespace oneapi::mkl::vm {

sycl::event log2(sycl::queue & exec_queue,
      T const * a,
      oneapi::mkl::slice sa,
      T * y,
      oneapi::mkl::slice sy,
      std::vector<sycl::event> const & depends = {},
      oneapi::mkl::vm::mode mode = oneapi::mkl::vm::mode::not_defined,
      oneapi::mkl::vm::error_handler<T> errhandler = {});

}

log2 supports the following precisions and devices:

T	Devices supported
`float`	CPU and GPU
`double`	CPU and GPU

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 containing the input vector.
sa: Slice selector for a. See Data Types for a description of the oneMKL slice type.
sy: Slice selector for y. See Data Types for a description of the oneMKL slice type.
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 to the input vector.
sa: Slice selector for a. See Data Types for a description of the oneMKL slice type.
sy: Slice selector for y. See Data Types for a description of the oneMKL slice type.
depends: Vector of dependent events (to wait for input data to be ready). This is an optional parameter. The default is an empty vector.
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 containing the output vector.
return value (event): Computation end event.

USM API

y: Pointer to the output vector.
return value (event): Computation end event..

Examples

An example of how to use log2 can be found in the oneMKL installation directory, under:

examples/dpcpp/vml/source/vlog2.cpp

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Intel® oneAPI Math Kernel Library (oneMKL) - Data Parallel C++ Developer Reference

log2

Description

API

Examples