SelectScalarFromRows

#include <popops/SelectScalarFromRows.hpp>

Select values from rows of a tensor.

namespace popops

Common functions, such as elementwise and reductions.

Functions

poplar::Tensor selectScalarFromRows(poplar::Graph &graph, const poplar::Tensor &params, const poplar::Tensor &indices, poplar::program::Sequence &prog, const poplar::DebugContext &debugContext = {})

For each row in the 2D tensor params, select a single scalar value.

Aggregate the resulting scalars into a 1D tensor.

The size of the indices tensor must be equal to the size of dimension 0 of params. The ith element of indices represents an index in the ith row of the params tensor.

If ith element of the indices tensor is less than 0 or greater than the width of params then a NaN is stored into the ith element of the output. If the ith element of the indices tensor is equal to MASKED_LABEL_CODE then zero is stored into the ith element of the output.

Parameters

  • graph – The Poplar graph.

  • params – A 2D tensor, the element type must be either float or half.

  • indices – A 1D tensor, the element type must be unsigned integer.

  • prog – The program to be extended.

  • debugContext – Optional debug information.

Returns

A 1D tensor containing in the ith position the scalar params[indices[i]].