102 lines
2.6 KiB
C++
102 lines
2.6 KiB
C++
/*
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* Tensor5Expression.h
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* @brief Tensor expression templates based on http://www.gps.caltech.edu/~walter/FTensor/FTensor.pdf
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* Created on: Feb 10, 2010
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* @author: Frank Dellaert
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*/
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#pragma once
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#include <iostream>
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#include "tensors.h"
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namespace tensors {
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/** templated class to interface to an object A as a rank 3 tensor */
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template<class A, class I, class J, class K, class L, class M> class Tensor5Expression {
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A iter;
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typedef Tensor5Expression<A, I, J, K, L, M> This;
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/** Helper class for swapping indices 3 and 4 :-) */
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class Swap34_ {
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const A iter;
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public:
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Swap34_(const A &a) :
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iter(a) {
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}
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double operator()(int i, int j, int k, int l, int m) const {
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return iter(i, j, l, k, m);
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}
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};
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public:
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/** constructor */
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Tensor5Expression(const A &a) :
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iter(a) {
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}
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/** Print */
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void print(const std::string& s = "Tensor5:") const {
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std::cout << s << std::endl;
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for (int m = 0; m < M::dim; m++)
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for (int l = 0; l < L::dim; l++)
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for (int k = 0; k < K::dim; k++) {
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std::cout << "(m,l,k) = (" << m << "," << l << "," << k << ")"
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<< std::endl;
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for (int j = 0; j < J::dim; j++) {
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for (int i = 0; i < I::dim; i++)
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std::cout << " " << (*this)(i, j, k, l, m);
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std::cout << std::endl;
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}
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}
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std::cout << std::endl;
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}
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/** swap indices */
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typedef Tensor5Expression<Swap34_, I, J, L, K, M> Swapped;
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Swapped swap34() {
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return Swap34_(iter);
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}
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/** element access */
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double operator()(int i, int j, int k, int l, int m) const {
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return iter(i, j, k, l, m);
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}
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}; // Tensor5Expression
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/** Print */
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template<class A, class I, class J, class K, class L, class M>
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void print(const Tensor5Expression<A, I, J, K, L, M>& T,
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const std::string& s = "Tensor5:") {
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T.print(s);
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}
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/** Helper class for outer product of rank3 and rank2 tensor */
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template<class A, class I, class J, class K, class B, class L, class M>
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class Rank3Rank2_ {
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typedef Tensor3Expression<A, I, J, K> Rank3;
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typedef Tensor2Expression<B, L, M> Rank2;
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const Rank3 iterA;
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const Rank2 iterB;
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public:
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Rank3Rank2_(const Rank3 &a, const Rank2 &b) :
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iterA(a), iterB(b) {
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}
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double operator()(int i, int j, int k, int l, int m) const {
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return iterA(i, j, k) * iterB(l, m);
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}
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};
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/** outer product of rank2 and rank1 tensor */
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template<class A, class I, class J, class K, class B, class L, class M>
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inline Tensor5Expression<Rank3Rank2_<A, I, J, K, B, L, M> , I, J, K, L, M> operator*(
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const Tensor3Expression<A, I, J, K>& a,
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const Tensor2Expression<B, L, M> &b) {
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return Rank3Rank2_<A, I, J, K, B, L, M> (a, b);
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}
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} // namespace tensors
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