p3d_index2ijk.m

function [i, j, k] = p3d_index2ijk(index, nx, ny)
% author: Ainray
% date: 20220831
% bug-report: wwzhang0421@163.com
% introduction: index 2 ijk, i, k, k and index starting with zero
% modify:

k = floor(index/(nx*ny));

% if k * nx * ny < index
%     k = k + 1;
% end
kr = index - k * (nx * ny);
j = floor(kr/nx);
% if j * nx < kr
%     j = j + 1;
% end
jr = kr - j*nx;
i = jr;