sub

oneMKL - Data Parallel C++ Developer Reference

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ID 772045

Date 3/31/2021

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sub

Computes the element-wise subtraction of vector b from vector a.

Description
API
Examples

Description

The sub(a, b) function performs element by element subtraction of vector a and vector b.

Argument 1	Argument 2	Result
+0	+0	+0
+0	-0	+0
-0	+0	+0
-0	-0	-0
+	+	QNAN
+	-	+
-	+	-
-	-	QNAN
SNAN	any value	QNAN
any value	SNAN	QNAN

Specifications for special values of the complex functions are defined according to the following formula:

sub(x1+i*y1,x2+i*y2) = (x1-x2) + i*(y1-y2)

Overflow in a complex function occurs (supported in the HA/LA accuracy modes only) when all RE(x), RE(y), IM(x), IM(y) arguments are finite numbers, but the real or imaginary part of the computed result is so large that it does not fit the target precision. In this case, the function returns in that part of the result, and sets the VM Error Status to status::overflow (overriding any possible status::accuracy_warning status).

API

Syntax

Buffer API

namespace oneapi::mkl::vm {

sycl::event sub(sycl::queue & exec_queue,
      std::int64_t n,
      sycl::buffer<T> & a,
      sycl::buffer<T> & b,
      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 sub(sycl::queue & exec_queue,
      sycl::buffer<T> & a,
      oneapi::mkl::slice sa,
      sycl::buffer<T> & b,
      oneapi::mkl::slice sb,
      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 sub(sycl::queue & exec_queue,
      std::int64_t n,
      T const * a,
      T const * b,
      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 sub(sycl::queue & exec_queue,
      T const * a,
      oneapi::mkl::slice sa,
      T const * b,
      oneapi::mkl::slice sb,
      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 = {});

}

sub supports the following precisions and devices:

T	Devices supported
`float`	CPU and GPU
`double`	CPU and GPU
`std::complex<float>`	CPU and GPU
`std::complex<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 1st input vector.
sa: Slice selector for a. See Data Types for a description of the oneMKL slice type.
b: The buffer containing the 2nd input vector.
sb: Slice selector for b. 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 1st input vector.
sa: Slice selector for a. See Data Types for a description of the oneMKL slice type.
b: Pointer to the 2nd input vector.
sb: Slice selector for b. 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 sub can be found in the oneMKL installation directory, under:

examples/dpcpp/vml/source/vsub.cpp

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oneMKL - Data Parallel C++ Developer Reference

sub

Description

API

Examples