Functions that perform parallel reductions on a GPU. More...

Functions
cudaReal	Pscf::Reduce::sum (DeviceArray< cudaReal > const &in)
	Return sum of elements of a real array.
cudaReal	Pscf::Reduce::sum (DeviceArray< cudaReal > const &in, int begin, int end)
	Return sum of elements of a real array slice.
std::complex< cudaReal >	Pscf::Reduce::sum (DeviceArray< cudaComplex > const &in)
	Return sum of all elements of a complex array.
std::complex< cudaReal >	Pscf::Reduce::sum (DeviceArray< cudaComplex > const &in, int begin, int end)
	Return sum of elements of a complex array slice.
cudaReal	Pscf::Reduce::sumSq (DeviceArray< cudaReal > const &in)
	Return sum of squares of elements of a real array.
std::complex< cudaReal >	Pscf::Reduce::sumSq (DeviceArray< cudaComplex > const &in)
	Return sum of squares of elements of a complex array.
cudaReal	Pscf::Reduce::sumSqAbs (DeviceArray< cudaComplex > const &in)
	Return sum of squared magnitudes of elements of a complex array.
cudaReal	Pscf::Reduce::innerProduct (DeviceArray< cudaReal > const &a, DeviceArray< cudaReal > const &b)
	Return the inner product of two real arrays.
cudaReal	Pscf::Reduce::max (DeviceArray< cudaReal > const &in)
	Return maximum of all real array elements.
cudaReal	Pscf::Reduce::max (DeviceArray< cudaReal > const &in, int begin, int end)
	Return maximum of elements of a real array slice.
cudaReal	Pscf::Reduce::maxAbs (DeviceArray< cudaReal > const &in)
	Get maximum absolute magnitude of real array elements.
cudaReal	Pscf::Reduce::min (DeviceArray< cudaReal > const &in)
	Return minimum of all real array elements.
cudaReal	Pscf::Reduce::min (DeviceArray< cudaReal > const &in, int begin, int end)
	Return minimum of elements of a real array slice.
cudaReal	Pscf::Reduce::minAbs (DeviceArray< cudaReal > const &in)
	Return minimum absolute magnitude of real array elements.
void	Pscf::Reduce::freeWorkSpace ()
	Free any private work space currently allocated for reductions.

Detailed Description

Functions that perform parallel reductions on a GPU.

A reduction is any operation that involves reducing all of the elements of one or more arrays to a single scalar result. Examples include taking the computation of the sum or the maximum of all elements of a single array, or of a Euclidean inner product of two real arrays.

A public function is provided for each reduction operation, which takes one or more DeviceArray containers as inputs and returns a single value. Each wrapper function is a standard C++ function that may be called on the host CPU. The implementation of each such wrapper function calls one of the device-wide algorithms defined in the CUB library that is distributed as part of the CUDA Core Compute library collection provided with the CUDA development kit.

Reduction functions that return a real number return a value of type cudaReal. Functions that return a complex number instead return a value of type std::complex<cudaReal>. Complex values are returned as std::complex<cudaReal> rather than cudaComplex to allow similar interfaces to be used by reduction functions declared here and by analogous functions defined in src/pscf/cpu/Reduced.h that take take standard Array containers as inputs and perform calculations on the CPU.

Function Documentation

◆ sum() [1/4]

cudaReal Pscf::Reduce::sum ( DeviceArray< cudaReal > const & in )

Return sum of elements of a real array.

Parameters

in	real input array

Returns: sum of elements

Definition at line 216 of file Reduce.cu.

References Pscf::DeviceArray< Data >::capacity(), Pscf::DeviceArray< Data >::cArray(), Pscf::DeviceArray< Data >::isAllocated(), sum(), and UTIL_CHECK.

◆ sum() [2/4]

cudaReal Pscf::Reduce::sum	(	DeviceArray< cudaReal > const &	in,
		int	begin,
		int	end )

Return sum of elements of a real array slice.

Parameters

in	real input array
begin	index of first element of slice
end	index one past last element

Returns: sum of elements

Definition at line 231 of file Reduce.cu.

References Pscf::DeviceArray< Data >::capacity(), Pscf::DeviceArray< Data >::cArray(), Pscf::DeviceArray< Data >::isAllocated(), sum(), and UTIL_CHECK.

◆ sum() [3/4]

std::complex< cudaReal > Pscf::Reduce::sum ( DeviceArray< cudaComplex > const & in )

Return sum of all elements of a complex array.

Parameters

in	complex input array

Returns: complex sum of elements

Definition at line 249 of file Reduce.cu.

References Pscf::DeviceArray< Data >::capacity(), Pscf::DeviceArray< Data >::cArray(), Pscf::DeviceArray< Data >::isAllocated(), sum(), and UTIL_CHECK.

◆ sum() [4/4]

std::complex< cudaReal > Pscf::Reduce::sum	(	DeviceArray< cudaComplex > const &	in,
		int	begin,
		int	end )

Return sum of elements of a complex array slice.

Parameters

in	real input array
begin	index of first element of slice
end	index one past last element of slice

Returns: sum of elements

Definition at line 264 of file Reduce.cu.

References Pscf::DeviceArray< Data >::capacity(), Pscf::DeviceArray< Data >::cArray(), Pscf::DeviceArray< Data >::isAllocated(), sum(), and UTIL_CHECK.

◆ sumSq() [1/2]

cudaReal Pscf::Reduce::sumSq ( DeviceArray< cudaReal > const & in )

Return sum of squares of elements of a real array.

This function returns the square of the Euclidean norm for a real array.

Parameters

in	real input array

Returns: sum of squares of elements

Definition at line 281 of file Reduce.cu.

References Pscf::DeviceArray< Data >::associate(), Pscf::DeviceArray< Data >::capacity(), Pscf::DeviceArray< Data >::dissociate(), Pscf::DeviceArray< Data >::isAllocated(), Pscf::VecOp::sqV(), sum(), and UTIL_CHECK.

◆ sumSq() [2/2]

std::complex< cudaReal > Pscf::Reduce::sumSq ( DeviceArray< cudaComplex > const & in )

Return sum of squares of elements of a complex array.

This function returns the complex sum of complex squares of elements. This is not the square of the Hilbert space norm.

Parameters

in	real input array

Returns: sum of complex squares of elements

Definition at line 304 of file Reduce.cu.

References Pscf::DeviceArray< Data >::associate(), Pscf::DeviceArray< Data >::capacity(), Pscf::DeviceArray< Data >::dissociate(), Pscf::DeviceArray< Data >::isAllocated(), Pscf::VecOp::sqV(), sum(), and UTIL_CHECK.

◆ sumSqAbs()

cudaReal Pscf::Reduce::sumSqAbs ( DeviceArray< cudaComplex > const & in )

Return sum of squared magnitudes of elements of a complex array.

This function returns the real sum of the squared absolute magnitude of all elements of a complex array. This is the square of the conventional Hilbert space norm.

Parameters

in	real input array

Returns: sum of squared absolute magnitude of elements

Definition at line 328 of file Reduce.cu.

References Pscf::DeviceArray< Data >::associate(), Pscf::DeviceArray< Data >::capacity(), Pscf::DeviceArray< Data >::dissociate(), Pscf::DeviceArray< Data >::isAllocated(), Pscf::VecOp::sqAbsV(), sum(), and UTIL_CHECK.

◆ innerProduct()

cudaReal Pscf::Reduce::innerProduct	(	DeviceArray< cudaReal > const &	a,
		DeviceArray< cudaReal > const &	b )

Return the inner product of two real arrays.

Parameters

a	first real input array
b	second real input array

Returns: Euclidean inner product

Definition at line 352 of file Reduce.cu.

References Pscf::DeviceArray< Data >::associate(), Pscf::DeviceArray< Data >::capacity(), Pscf::DeviceArray< Data >::dissociate(), Pscf::DeviceArray< Data >::isAllocated(), Pscf::VecOp::mulVV(), sum(), and UTIL_CHECK.

◆ max() [1/2]

cudaReal Pscf::Reduce::max ( DeviceArray< cudaReal > const & in )

Return maximum of all real array elements.

Parameters

in	real input array

Returns: value of maximum element

Definition at line 381 of file Reduce.cu.

References Pscf::DeviceArray< Data >::capacity(), Pscf::DeviceArray< Data >::cArray(), Pscf::DeviceArray< Data >::isAllocated(), max(), and UTIL_CHECK.

◆ max() [2/2]

cudaReal Pscf::Reduce::max	(	DeviceArray< cudaReal > const &	in,
		int	begin,
		int	end )

Return maximum of elements of a real array slice.

Parameters

in	real input array
begin	index of first element of slice
end	index one past last element

Returns: value of maximum element

Definition at line 394 of file Reduce.cu.

References Pscf::DeviceArray< Data >::capacity(), Pscf::DeviceArray< Data >::cArray(), Pscf::DeviceArray< Data >::isAllocated(), max(), and UTIL_CHECK.

◆ maxAbs()

cudaReal Pscf::Reduce::maxAbs ( DeviceArray< cudaReal > const & in )

Get maximum absolute magnitude of real array elements.

Parameters

in	real input array

Returns: magnitude of element of maximum magnitude

Definition at line 410 of file Reduce.cu.

References Pscf::VecOp::absV(), Pscf::DeviceArray< Data >::associate(), Pscf::DeviceArray< Data >::capacity(), Pscf::DeviceArray< Data >::dissociate(), Pscf::DeviceArray< Data >::isAllocated(), max(), and UTIL_CHECK.

◆ min() [1/2]

cudaReal Pscf::Reduce::min ( DeviceArray< cudaReal > const & in )

Return minimum of all real array elements.

Parameters

in	real input array

Returns: value of minimum element

Definition at line 436 of file Reduce.cu.

References Pscf::DeviceArray< Data >::capacity(), Pscf::DeviceArray< Data >::cArray(), Pscf::DeviceArray< Data >::isAllocated(), min(), and UTIL_CHECK.

◆ min() [2/2]

cudaReal Pscf::Reduce::min	(	DeviceArray< cudaReal > const &	in,
		int	begin,
		int	end )

Return minimum of elements of a real array slice.

Parameters

in	real input array
begin	index of first element of slice
end	index one past last element

Returns: value of minimum element

Definition at line 449 of file Reduce.cu.

References Pscf::DeviceArray< Data >::capacity(), Pscf::DeviceArray< Data >::cArray(), Pscf::DeviceArray< Data >::isAllocated(), min(), and UTIL_CHECK.

◆ minAbs()

cudaReal Pscf::Reduce::minAbs ( DeviceArray< cudaReal > const & in )

Return minimum absolute magnitude of real array elements.

Parameters

in	real input array

Returns: magnitude of element of minimum magnitude

Definition at line 465 of file Reduce.cu.

References Pscf::VecOp::absV(), Pscf::DeviceArray< Data >::associate(), Pscf::DeviceArray< Data >::capacity(), Pscf::DeviceArray< Data >::dissociate(), Pscf::DeviceArray< Data >::isAllocated(), min(), and UTIL_CHECK.

◆ freeWorkSpace()

void Pscf::Reduce::freeWorkSpace ( )

Free any private work space currently allocated for reductions.

Definition at line 203 of file Reduce.cu.