Hi Alex, have you had a chance to read some of our knowledge base articles? We have a variety of code examples in those articles that demonstrate the use of map() which is what you need to be using in the situation you described.

If you go to the KB article entitled Array Building Blocks Code Samplesyou will see awide variety of code sample descriptions, most notably the examples of 1D, 2D, and 3D convolution, which is doing exactly what you are seeking. Samples are grouped into directories corresponding to application areas (categories) such as /samples/imaging, /samples/seismic and so on. Have you run those samples?

Seems like you are looking for the method arbb::section (see documentation) that provides a small dense array out of a larger dense array (i.e. sub-matrix). Then you can do whatever you want with the returned dense array.