c_STRIDED example for span

[ib00]

Is there an example of how to use c_STRIDED layout for span?

[tylov]

Yes, in the span_demo.c example it is used it make a "downsampled view" of an image in each direction, using the cspan_shape() and cspan_strides() macros.

    Span2 img = cspan_md(md3.data, 6, 10);
    Span2 half = {img.data, cspan_shape(img.shape[0]/2, img.shape[1]/2),
                            cspan_strides(img.stride.d[0]*2, img.stride.d[1]*2)};

[ib00]

Would you ever use c_STRIDED layout to construct a span with custom strides? Or is that undesirable practice?

[tylov]

I don't actually use linear algebra much outside of 3d graphics, but I think it is used yes. You just have to make sure that the index() function always returns an index inside your data array for valid inputs - the range checking only checks that the input indices are within the shape sizes.