I have a problem in speeding my code. In my code, there is a step as below,
In practice, the matrix a and index are very large n*3 matrix. a is the node coordinates and the index is the triangle face index of the node. The surface is too big. So I really need to speed this loop. I have an idea that vectorization could make the code faster. But I could not get the ideal output result, even with some matrix "resize" or matrix rotation functions, like "resize" or "reshape". I am very thankful for any suggestion.