erf

Computes the error function value of vector elements.

Syntax

Buffer API:

void erf(queue &exec_queue, int64_t n, buffer<T, 1> &a, buffer<T, 1> &y, uint64_t mode = mode::not_defined)

USM API:

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

erf supports the following precisions and devices:

T

Devices supported

float

Host, CPU, and GPU

double

Host, CPU, and GPU

Description

The erf function computes the error function values for elements of the input vector a and writes them to the output vector y.

The error function is defined as given by:

image0

Useful relations:

image1

where erfc is the complementary error function.

image2

where

image3

is the cumulative normal distribution function.

image4

where Φ-1(x) and erf-1(x) are the inverses to Φ(x) and erf(x), respectively.

The following figure illustrates the relationships among erf family functions (erf, erfc, cdfnorm).

erf Family Functions Relationship |

image5

Useful relations for these functions:

image6


image7

Argument

Result

Error Code

+∞

+1

-∞

-1

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.

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 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.

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 erfcan be found in the Intel® oneMKL installation directory, under:

examples/sycl/vml/verf.cpp