code: public static void negative( InterleavedS16 input , InterleavedS16 output ) {
  
  		output.reshape(input.width,input.height);
  
  		int columns = input.width*input.numBands;
  		if(BoofConcurrency.USE_CONCURRENT ) {
  			ImplPixelMath_MT.negative(input.data, input.startIndex, input.stride,
  					output.data, output.startIndex, output.stride,
  					input.height, columns);
  		} else {
  			ImplPixelMath.negative(input.data, input.startIndex, input.stride,
  					output.data, output.startIndex, output.stride,
  					input.height, columns);
  		}
  	}
docs: Changes the sign of every pixel in the image: output[x,y] = -input[x,y]
  
  @param input The input image. Not modified.
  @param output Where the negated image is written to. Modified.