code: public static int[] unravelIndex(int configIx, int... dims) {
          int numConfigs = IntArrays.prod(dims);
          assert configIx < numConfigs;
          int[] strides = getStrides(dims);
          return unravelIndexFromStrides(configIx, strides);
      }
docs: Returns an integer array of the same length as dims that matches the configIx'th configuration
  if enumerated configurations in order such that the leftmost dimension changes slowest