yakl::ScalarLiveOut< T > Class Template Reference

Class to handle scalars that exist before kernels, are written to by kernels, and read after the kernel terminates. More...

#include <YAKL_ScalarLiveOut.h>

Public Member Functions
YAKL_INLINE	ScalarLiveOut ()
	Default constructor allocates room on the device for one scalar of type T More...
YAKL_INLINE	ScalarLiveOut (ScalarLiveOut &&rhs)
	Copies and moves are shallow, not deep copy. More...
YAKL_INLINE	ScalarLiveOut (ScalarLiveOut const &rhs)
	Copies and moves are shallow, not deep copy. More...
	ScalarLiveOut (T val, Stream stream=Stream())
	[ASYNCHRONOUS] This constructor allocates room on the device for one scalar of type T and initializes it on device with the provided value. More...
YAKL_INLINE	~ScalarLiveOut ()
	Deallocates the scalar value on the device. More...
YAKL_INLINE T	get () const
	Returns a modifiable reference to the underlying data on the device. More...
T	hostRead (Stream stream=Stream()) const
	Returns a host copy of the data. This is blocking. More...
void	hostWrite (T val, Stream stream=Stream())
	[ASYNCHRONOUS] Writes a value to the device-resident underlying data More...
YAKL_INLINE T &	operator() () const
	Returns a modifiable reference to the underlying data on the device. More...
YAKL_INLINE ScalarLiveOut &	operator= (ScalarLiveOut &&rhs)
	Copies and moves are shallow, not deep copy. More...
YAKL_INLINE ScalarLiveOut &	operator= (ScalarLiveOut const &rhs)
	Copies and moves are shallow, not deep copy. More...
template<class TLOC , typename std::enable_if< std::is_arithmetic< TLOC >::value, int >::type = 0>
YAKL_INLINE T &	operator= (TLOC rhs) const
	Assign a value to the ScalarLiveOut object on the device. More...

Detailed Description

template<class T>
class yakl::ScalarLiveOut< T >

Class to handle scalars that exist before kernels, are written to by kernels, and read after the kernel terminates.

Handles the case where a scalar value is written to in a kernel and must be read on the host after the kernel completes. Passing a value to the constructor will initialize the device pointer with that data from the host. Using the = operator will assign to the value inside a kernel. This is the most common operation. To access the value as a reference that is writable, use the operator() (e.g., in an atomic operation perhaps). To read on the host afterward, using hostRead() To write after construction, use hostWrite()

ScalarLiveOut<float> sum(0.);
// You'd use a reduction for this in reality. This is just for demonstration.
parallel_for( Bounds<2>(ny,nx) , YAKL_LAMBDA (int j, int i) {
  // sum() obtains a modifiable reference to the data contained by the ScalarLiveOut object
  atomicAdd( sum() , 1. );
});
if (sum.hostRead() != ny*nx) yakl::yakl_throw("ERROR: Wrong sum");

ScalarLiveOut<bool> data_is_bad(false);
parallel_for( Bounds<2>(ny,nx) , YAKL_LAMBDA (int j, int i) {
  // operator= always assigns on the device
  if (density(j,i) < 0) data_is_bad = true;
});
if (data_is_bad.hostRead()) yakl::yakl_throw("ERROR: Data is bad");

Parameters

T	The type of the scalar value

Constructor & Destructor Documentation

ScalarLiveOut() [1/4]

template<class T >

YAKL_INLINE yakl::ScalarLiveOut< T >::ScalarLiveOut ( )

inline

Default constructor allocates room on the device for one scalar of type T

ScalarLiveOut() [2/4]

template<class T >

yakl::ScalarLiveOut< T >::ScalarLiveOut ( T  val, Stream  stream = Stream()  )

inlineexplicit

[ASYNCHRONOUS] This constructor allocates room on the device for one scalar of type T and initializes it on device with the provided value.

~ScalarLiveOut()

template<class T >

YAKL_INLINE yakl::ScalarLiveOut< T >::~ScalarLiveOut ( )

inline

Deallocates the scalar value on the device.

ScalarLiveOut() [3/4]

template<class T >

YAKL_INLINE yakl::ScalarLiveOut< T >::ScalarLiveOut ( ScalarLiveOut< T > const &  rhs )

inline

Copies and moves are shallow, not deep copy.

ScalarLiveOut() [4/4]

template<class T >

YAKL_INLINE yakl::ScalarLiveOut< T >::ScalarLiveOut ( ScalarLiveOut< T > &&  rhs )

inline

Copies and moves are shallow, not deep copy.

Member Function Documentation

get()

template<class T >

YAKL_INLINE T yakl::ScalarLiveOut< T >::get ( ) const

inline

Returns a modifiable reference to the underlying data on the device.

hostRead()

template<class T >

T yakl::ScalarLiveOut< T >::hostRead ( Stream  stream = Stream() ) const

inline

Returns a host copy of the data. This is blocking.

hostWrite()

template<class T >

void yakl::ScalarLiveOut< T >::hostWrite ( T  val, Stream  stream = Stream()  )

inline

[ASYNCHRONOUS] Writes a value to the device-resident underlying data

operator()()

template<class T >

YAKL_INLINE T& yakl::ScalarLiveOut< T >::operator() ( ) const

inline

Returns a modifiable reference to the underlying data on the device.

operator=() [1/3]

template<class T >

YAKL_INLINE ScalarLiveOut& yakl::ScalarLiveOut< T >::operator= ( ScalarLiveOut< T > &&  rhs )

inline

Copies and moves are shallow, not deep copy.

operator=() [2/3]

template<class T >

YAKL_INLINE ScalarLiveOut& yakl::ScalarLiveOut< T >::operator= ( ScalarLiveOut< T > const &  rhs )

inline

Copies and moves are shallow, not deep copy.

operator=() [3/3]

template<class T >

template<class TLOC , typename std::enable_if< std::is_arithmetic< TLOC >::value, int >::type = 0>

YAKL_INLINE T& yakl::ScalarLiveOut< T >::operator= ( TLOC  rhs ) const

inline

Assign a value to the ScalarLiveOut object on the device.

---

The documentation for this class was generated from the following file:

• YAKL/src/YAKL_ScalarLiveOut.h