lgamma

Computes the natural logarithm of the absolute value of gamma function for vector elements.

Syntax

Buffer API:

void lgamma(queue &exec_queue, int64_t n, buffer<T, 1> &a, buffer<T, 1> &y, uint64_t mode = mode::not_defined, error_handler<T> errhandler = {})

USM API:

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

lgamma supports the following precisions and devices:

T

Devices supported

float

Host and CPU

double

Host and CPU

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

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.

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 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.

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

examples/sycl/vml/vlgamma.cpp