docs: void precomputeAngles(D image) {
  		int savecIndex = 0;
  		for (int y = 0; y < image.height; y++) {
  			int pixelIndex = y*image.stride + image.startIndex;
  
  			for (int x = 0; x < image.width; x++, pixelIndex++, savecIndex++ ) {
  				float spacialDX = imageDerivX.getF(pixelIndex);
  				float spacialDY = imageDerivY.getF(pixelIndex);
  
  				savedAngle.data[savecIndex] = UtilAngle.domain2PI(Math.atan2(spacialDY,spacialDX));
  				savedMagnitude.data[savecIndex] = (float)Math.sqrt(spacialDX*spacialDX + spacialDY*spacialDY);
  			}
  		}
  	}