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Added iterator for Eigen tensors

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This commit is contained in:
Michael Marshall 2019-03-25 15:50:29 +00:00
parent b3b9e608e1
commit d1e02f50ff
1 changed files with 85 additions and 0 deletions
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85
Grid/util/EigenUtil.h
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@ -30,6 +30,83 @@
#include <Grid/tensors/Tensor_traits.h>
#include <Grid/Eigen/unsupported/CXX11/Tensor>
namespace Grid {
// Custom iterator for Eigen tensors
namespace EigenUtil {
template <typename ETensor, bool bConst> // Is the tensor constant
class TensorIterator_raw{
public:
using Index = typename ETensor::Index;
using Scalar = typename ETensor::Scalar;
using FullIndex = std::array<Index, ETensor::NumIndices>;
const ETensor * pET;
const Index end; // same as pET->size()
Index position; // position (memory order)
Index Seq; // sequence (what our position would be if we were column major)
FullIndex indexPos;
FullIndex indexSize;
inline TensorIterator_raw( ETensor & eT, Index pos = 0 ) : pET{&eT}, position{pos}, Seq{pos}, end{pET->size()} {
for( int i = 0 ; i < ETensor::NumIndices ; i++ ) {
indexPos[i] = 0;
indexSize[i] = pET->dimension(i);
}
}
inline TensorIterator_raw<ETensor, bConst> & operator++() {
auto sz = pET->size();
if( position < sz ) {
position++;
if( ETensor::Options & Eigen::RowMajor ) {
for( int i = ETensor::NumIndices - 1; i != -1 && ++indexPos[i] == indexSize[i]; i-- )
indexPos[i] = 0;
Seq++;
} else {
for( int i = 0; i < ETensor::NumIndices && ++indexPos[i] == indexSize[i]; i++ )
indexPos[i] = 0;
Seq = 0;
for( int i = 0; i < ETensor::NumIndices; i++ ) {
Seq *= indexSize[i];
Seq += indexPos[i];
}
}
}
return * this;
}
inline typename std::conditional<bConst,const Scalar &,Scalar &>::type operator*() const {
assert( position >= 0 && position < pET->size() && "Attempt to access Eigen tensor iterator out of range" );
return ( ( typename std::conditional<bConst,const Scalar *,Scalar*>::type ) pET->data() )[position];
}
inline bool operator!=(const TensorIterator_raw<ETensor, bConst> &r)
{ return pET == nullptr || pET != r.pET || position != r.position; }
// These functions aren't rerquired for iterators, but they make using them easier
inline bool AtEnd() { return position == end; }
inline void DumpIndex(void) {
for( auto dim : indexPos )
std::cout << "[" << dim << "]";
}
};
}
}
// The only way I could get these iterators to work is to put the begin() and end() functions in the Eigen namespace
// So if Eigen ever defines these, we'll have a conflict and have to change this
namespace Eigen {
template <typename ETensor> using TensorIterator = Grid::EigenUtil::TensorIterator_raw< ETensor, false>;
template <typename ETensor> using TensorIteratorConst = Grid::EigenUtil::TensorIterator_raw<const ETensor, true>;
template <typename ETensor>
inline typename std::enable_if<Grid::EigenIO::is_tensor<ETensor>::value, TensorIterator<ETensor>>::type
begin( ETensor & ET ) { return TensorIterator<ETensor>(ET); }
template <typename ETensor>
inline typename std::enable_if<Grid::EigenIO::is_tensor<ETensor>::value, TensorIterator<ETensor>>::type
end( ETensor & ET ) { return TensorIterator<ETensor>(ET, ET.size()); }
template <typename ETensor>
inline typename std::enable_if<Grid::EigenIO::is_tensor<ETensor>::value, TensorIteratorConst<ETensor>>::type
begin( const ETensor & ET ) { return TensorIteratorConst<ETensor>(ET); }
template <typename ETensor>
inline typename std::enable_if<Grid::EigenIO::is_tensor<ETensor>::value, TensorIteratorConst<ETensor>>::type
end( const ETensor & ET ) { return TensorIteratorConst<ETensor>(ET, ET.size()); }
}
namespace Grid {
// for_all helper function to call the lambda for scalar
template <typename ETensor, typename Lambda>
@ -174,6 +251,7 @@ namespace Grid {
for( int i = 0 ; i < rank; i++ ) std::cout << "[" << dims[i] << "]";
for( int i = 0 ; i < Traits::Rank; i++ ) std::cout << "(" << Traits::Dimension(i) << ")";
std::cout << " in memory order:" << std::endl;
#ifdef OLD_DEFINITION
for_all( t, [&](scalar_type &c, Index n, const std::array<Index, rank> &TensorIndex,
const std::array<int, Traits::Rank> &ScalarIndex ){
std::cout << " ";
@ -183,6 +261,13 @@ namespace Grid {
std::cout << "(" << dim << ")";
std::cout << " = " << c << std::endl;
} );
#else
for( auto it = begin(t); !it.AtEnd(); ++it ) {
std::cout << " ";
it.DumpIndex();
std::cout << " = " << (const typename T::Scalar)(*it) << std::endl;
}
#endif
std::cout << "========================================" << std::endl;
}