Visible to Intel only — GUID: GUID-C5FCC624-5CE2-41D9-AB38-0DF612AD5D7A
Visible to Intel only — GUID: GUID-C5FCC624-5CE2-41D9-AB38-0DF612AD5D7A
erf
Computes the element-wise error function of vector elements.
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:
![](/content/dam/docs/us/en/developer-reference-dpcpp/2023-1/3731AD71-6E2D-493D-8514-05A3D41B1DF9-low.png)
Useful relations:
![](/content/dam/docs/us/en/developer-reference-dpcpp/2023-1/53671448-7305-4653-9CB1-0617D69B67EF-low.png)
where erfc is the complementary error function.
![](/content/dam/docs/us/en/developer-reference-dpcpp/2023-1/9CBDB17A-160E-4730-A06A-C2106C1D2A2B-low.png)
where
![](/content/dam/docs/us/en/developer-reference-dpcpp/2023-1/6072E561-E9ED-4F50-B304-EA1AD9378261-low.png)
is the cumulative normal distribution function.
![](/content/dam/docs/us/en/developer-reference-dpcpp/2023-1/FE2C3C06-4220-4DED-8705-CA4A5FE7D599-low.png)
where and erf-1(x) are the inverses to
and erf(x), respectively.
The following figure illustrates the relationships among erf family functions (erf, erfc, cdfnorm).
![](/content/dam/docs/us/en/developer-reference-dpcpp/2023-1/3AFAACB6-2DE7-43D9-B19E-E1BC782ED10E-low.png)
Useful relations for these functions:
![](/content/dam/docs/us/en/developer-reference-dpcpp/2023-1/F0710479-52BE-4C95-A2FF-4B1C36702C73-low.png)
![](/content/dam/docs/us/en/developer-reference-dpcpp/2023-1/BAB20A37-5E70-414F-94D1-7BCD8AB67337-low.png)
Argument |
Result |
Error Code |
---|---|---|
+ |
+1 |
|
- |
-1 |
|
QNAN |
QNAN |
|
SNAN |
QNAN |
API
Syntax
Buffer API
namespace oneapi::mkl::vm { sycl::event erf(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); }
namespace oneapi::mkl::vm { sycl::event erf(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); }
USM API
namespace oneapi::mkl::vm { sycl::event erf(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); }
namespace oneapi::mkl::vm { sycl::event erf(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); }
erf 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 the 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 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.
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 erf can be found in the oneMKL installation directory, under:
examples/dpcpp/vml/source/verf.cpp