quantization.h

#pragma once

#include<cmath>

namespace Quantization {

	// NOTE: none of these values should be modified by the clients
	static const int BITS = 30;
	// MAGNIFY * RESHRINK == 1
	extern double MAGNIFY;
	extern double RESHRINK;
	inline int quantize2int(double number) {
		return int(number * MAGNIFY);
	}
	inline double quantizedInt2double(int number) {
		return RESHRINK * double(number);
	}
	inline double quantize(double number) {
		return RESHRINK * double(int(number * MAGNIFY));
	}

	// given the specified number of bits,
	// and bound on the coordinate values of points,
	// fit as fine-grained a grid as possible over the space.
	inline void callibrate(double maximumMagnitude)
	{
		int max_exponent;
		std::frexp(maximumMagnitude, &max_exponent);
		max_exponent++; // ensure that 2^max_exponent > maximumMagnitude

						// set constants
		MAGNIFY = std::pow(2.0, BITS - max_exponent);
		// we are guaranteed that maximumMagnitude * MAGNIFY < 2.0^BITS
		RESHRINK = std::pow(2.0, max_exponent - BITS);
	}
} // end namespace Quantization