src/main/cpp/kernels/agg_ops.cuh

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

#ifndef __AGG_OPS_H
#define __AGG_OPS_H

#pragma once

#include <cuda_runtime.h>

/**
 * Functor op for assignment op. This is a dummy/identity op.
 */
template<typename T>
struct IdentityOp {
	__device__  __forceinline__ T operator()(T a) const {
		return a;
	}
};

/**
 * Functor op for summation operation
 */
template<typename T>
struct SumOp {
	__device__  __forceinline__ T operator()(T a, T b) const {
		return a + b;
	}
};

/**
 * Functor op for min operation
 */
template<typename T>
struct MinOp {
	__device__  __forceinline__ T operator()(T a, T b) const {
		return fmin(a, b);
	}
};

/**
 * Functor op for max operation
 */
template<typename T>
struct MaxOp {
	__device__  __forceinline__ T operator()(T a, T b) const {
		return fmax(a, b);
	}
};

template<>
struct MaxOp<float> {
	__device__ __forceinline__ float operator()(float a, float b) const {
		return fmaxf(a, b);
	}
};

/**
 * Functor op for product operation
 */
template<typename T>
struct ProductOp {
	__device__  __forceinline__ T operator()(T a, T b) const {
		return a * b;
	}
};

/**
 * Functor op for mean operation
 */
template<typename T>
struct MeanOp {
	const long _size; ///< Number of elements by which to divide to calculate mean
	__device__ __forceinline__ MeanOp(long size) :
			_size(size) {
	}
	__device__  __forceinline__ T operator()(T total) const {
		return total / _size;
	}
};

template<typename T>
struct SumNeutralElement {
	static __device__ __forceinline__ T get();
};

template<>
float SumNeutralElement<float>::get() { return 0.0f; }

template<>
double SumNeutralElement<double>::get() { return 0.0; }


template<typename T>
struct ProdNeutralElement {
	static __device__ __forceinline__ T get();
};

template<>
float ProdNeutralElement<float>::get() { return 1.0f; }

template<>
double ProdNeutralElement<double>::get() { return 1.0; }

template<typename T>
struct MinNeutralElement {
	static __device__ __forceinline__ T get();
};

template<>
float MinNeutralElement<float>::get() { return INFINITY; }

template<>
double MinNeutralElement<double>::get() { return INFINITY; }

template<typename T>
struct MaxNeutralElement {
	static __device__ __forceinline__ T get();
};

template<>
float MaxNeutralElement<float>::get() { return -INFINITY; }

template<>
double MaxNeutralElement<double>::get() { return -INFINITY; }

#endif // __AGG_OPS_H