lgamma

oneMKL - Data Parallel C++ Developer Reference

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ID 772045

Date 6/24/2024

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lgamma

Computes the element-wise natural logarithm of the absolute value of the gamma function of vector elements.

Description
API
Examples

Description

The lgamma(a) function computes the natural logarithm of the absolute value of gamma function for elements of the input vector a and writes them to the output vector y. Precision overflow thresholds for the lgamma function are beyond the scope of this document. If the result does not meet the target precision, the function sets the VM Error Status to status::overflow.

Argument	Result	Error Code
+1	+0
+2	+0
+0	+	`status::sing`
-0	+	`status::sing`
negative integer	+	`status::sing`
-	+
+	+
a > overflow	+	`status::overflow`
QNAN	QNAN
SNAN	QNAN

API

Syntax

Buffer API

namespace oneapi::mkl::vm {

sycl::event lgamma(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 lgamma(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 lgamma(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 lgamma(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 = {});

}

lgamma supports the following precisions and devices:

T	Devices supported
`sycl::half`	GPU
`_Float16`	CPU
`float`	CPU
`double`	CPU

Input Parameters

Buffer API

exec_queue: The queue where the routine will 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 will 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 lgamma can be found in the oneMKL installation directory, under:

share/doc/mkl/examples/sycl/vml/source/vlgamma.cpp

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oneMKL - Data Parallel C++ Developer Reference

lgamma

Description

API

Examples