能量最小化初探，graphcuts能量最小化调用

/* energy.h */
/* Vladimir Kolmogorov (vnk@cs.cornell.edu), 2003. */

/*
	This software implements an energy minimization technique described in

	What Energy Functions can be Minimized via Graph Cuts?
	Vladimir Kolmogorov and Ramin Zabih. 
	To appear in IEEE Transactions on Pattern Analysis and Machine Intelligence (PAMI). 
	Earlier version appeared in European Conference on Computer Vision (ECCV), May 2002. 

	More specifically, it computes the global minimum of a function E of binary
	variables x_1, ..., x_n which can be written as a sum of terms involving
	at most three variables at a time:

		E(x_1, ..., x_n) = \sum_{i}     E^{i}    (x_i)
		                 + \sum_{i,j}   E^{i,j}  (x_i, x_j)
		                 + \sum_{i,j,k} E^{i,j,k}(x_i, x_j, x_k)

	The method works only if each term is "regular". Definitions of regularity
	for terms E^{i}, E^{i,j}, E^{i,j,k} are given below as comments to functions
	add_term1(), add_term2(), add_term3(). 

	This software can be used only for research purposes. IF YOU USE THIS SOFTWARE,
	YOU SHOULD CITE THE AFOREMENTIONED PAPER IN ANY RESULTING PUBLICATION.

	In order to use it, you will also need a MAXFLOW software which can be
	obtained from http://www.cs.cornell.edu/People/vnk/software.html


	Example usage
	(Minimizes the following function of 3 binary variables:
	E(x, y, z) = x - 2*y + 3*(1-z) - 4*x*y + 5*|y-z|):

	///////////////////////////////////////////////////

	#include <stdio.h>
	#include "energy.h"

	void test_energy()
	{
		// Minimize the following function of 3 binary variables:
		// E(x, y, z) = x - 2*y + 3*(1-z) - 4*x*y + 5*|y-z|
		   
		Energy::Var varx, vary, varz;
		Energy *e = new Energy();

		varx = e -> add_variable();
		vary = e -> add_variable();
		varz = e -> add_variable();

		e -> add_term1(varx, 0, 1);  // add term x ,常数项为0，一次项系数为1
		e -> add_term1(vary, 0, -2); // add term -2*y
		e -> add_term1(varz, 3, 0);  // add term 3*(1-z)

		//e -> add_term2(x, y, 0, 0, 0, -4); // add term -4*x*y
		//e -> add_term2(y, z, 0, 5, 5, 0); // add term 5*|y-z|

		Energy::TotalValue Emin = e -> minimize();
		
		printf("Minimum = %d\n", Emin);
		printf("Optimal solution:\n");
		printf("x = %d\n", e->get_var(varx));
		printf("y = %d\n", e->get_var(vary));
		printf("z = %d\n", e->get_var(varz));

		delete e;
	}

	///////////////////////////////////////////////////
*/