Greetings to Boosters,

I have a 3D multi_array and I would like to make 2D slices using dimensions specified at runtime. I know the index of degenerate dimension and an index of slice, that I want to extract in that degenerate dimension. Currently the ugly workaround looks like that:

    if (0 == degenerate_dimension)

    {

        Slice slice = input_array[boost::indices[slice_index][range()][range()]];

    }

    else if (1 == degenerate_dimension)

    {

        Slice slice = input_array[boost::indices[range()][slice_index][range()]];

    }

    else if (2 == degenerate_dimension)

    {

        Slice slice = input_array[boost::indices[range()][range()][slice_index]];

    }

 

Is there a more beautiful way to construct index_gen object?

Something like that:

    var slicer;

    for(int i = 0; i < 3; ++i) {

        if (degenerate_dimension == i)

            slicer = boost::indices[slice_index];

        else

            slicer = boost::indices[range()];

    }

    Slice slice = input_array[slicer];

It seems each subsequent call to boost::indices::operator[] returns a different type depending on the dimensionality, so there's no way to use a single variable, that can hold the temporary index_gen object.