Developer Reference

Contents

log2

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

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
-LaTex Math image.
status::sing
-0
-LaTex Math image.
status::sing
-LaTex Math image.
QNAN
status::errdom
+LaTex Math image.
+LaTex Math image.
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<cl::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<cl::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
Host, CPU, and GPU
double
Host, 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

Product and Performance Information

1

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