#define N 10
#define DEMAND 5000
#define FEE 3000.0

continuous Y[N]; 
continuous  X[N],Z;
double cap[N],cost[N];
int node_cnt;
int solu_cnt;

data()
{
cap = { 700, 1000, 1000, 1000, 400, 500, 4700, 9930, 3440, 7550 };
cost = { 18.0, 18.5, 20.0, 20.0, 14.0, 17.5, 22.0, 27.5, 24.5, 23.8 };
}

basic_constraints()
{
	and(int j=0;j<N;j++) 				// Bounding constraints
		X[j] <= cap[j];

	// Store’s demand constraint
	sigma(int j=0;j<N;j++)  X[j] >= DEMAND;

	and(int j=0;j<N;j++) 		
		Y[j] <= 1.0;
}

add_cuts()
{
	and(int i=0;i<N;i++)				// Valid cuts
		X[i] <= cap[i]*Y[i]; 
}

quick_and_dirty()				// After cuts
{
double scratch;

	min: Z;
	// Initialize scratch to be wp(Z) less the FEE*Y[i] 
	scratch = wp(sigma(int i=0;i<N;i++) cost[i]*X[i]);
	and(int i=0;i<N;i++) 
		if wp(X[i]) > 0;						// Supplier used ?
		then scratch = scratch + FEE;			// then pay fee
	Z <= scratch;				// A bluff for branch-and-bound
	printf("quick_and_dirty yields a cost of %f",scratch);
}

enforce(int i)
{
	either {
		node_cnt = node_cnt +1;
		Y[i] == 1.0;
	}
	or  {
		node_cnt = node_cnt +1; 
		X[i] == 0; 
		Y[i] == 0.0; 
	}
}

#define fail 0==1
determine_first_pair(int & bv)
{
	and(int i=0;i<N;i++) 
		if { 
			wp(X[i]) > 0.0; 
			wp(Y[i]) < 1.0; 
		}
		then {
			bv = i;
			return;
		}
	fail;
}

search()
{
int bv;
		
	and(;;){
		min: Z;
		if determine_first_pair(bv);
		then enforce(bv);					// New version
		else break;
	}
}

output()
{
	and(int i=0;i<N;i++) 
		printf("Order %f from supplier %d \n",X[i],i);
	printf("Total cost will be %f\n",Z);
	printf("Node count is %d \n",node_cnt);
	printf("Number of solutions is %d\n", solu_cnt); 
}

2lp_main()
{
	data();
	basic_constraints();
	add_cuts();
	Z == sigma(int i=0;i<N;i++) (cost[i]*X[i] + FEE*Y[i]);
	quick_and_dirty();				// Compute and enforce bluff

	find_min: Z;
	subject_to { 
		search();
		solu_cnt = solu_cnt+1;
	}
	output();
}
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