Impala Documentation

static void solve_nu_svc	(	const svm_problem *	prob,
		const svm_parameter *	param,
		double *	alpha,
		Solver::SolutionInfo *	si
	)			`[static]`

Definition at line 1288 of file svm.cpp.

References svm_problem::l, min, svm_parameter::nu, and svm_problem::y.

Referenced by svm_train_one().

01291 {
01292         int i;
01293         int l = prob->l;
01294         double nu = param->nu;
01295 
01296         schar *y = new schar[l];
01297 
01298         for(i=0;i<l;i++)
01299                 if(prob->y[i]>0)
01300                         y[i] = +1;
01301                 else
01302                         y[i] = -1;
01303 
01304         double sum_pos = nu*l/2;
01305         double sum_neg = nu*l/2;
01306 
01307         for(i=0;i<l;i++)
01308                 if(y[i] == +1)
01309                 {
01310                         alpha[i] = min(1.0,sum_pos);
01311                         sum_pos -= alpha[i];
01312                 }
01313                 else
01314                 {
01315                         alpha[i] = min(1.0,sum_neg);
01316                         sum_neg -= alpha[i];
01317                 }
01318 
01319         double *zeros = new double[l];
01320 
01321         for(i=0;i<l;i++)
01322                 zeros[i] = 0;
01323 
01324         Solver_NU s;
01325         s.Solve(l, SVC_Q(*prob,*param,y), zeros, y,
01326                 alpha, 1.0, 1.0, param->eps, si,  param->shrinking);
01327         double r = si->r;
01328 
01329         info("C = %f\n",1/r);
01330 
01331         for(i=0;i<l;i++)
01332                 alpha[i] *= y[i]/r;
01333 
01334         si->rho /= r;
01335         si->obj /= (r*r);
01336         si->upper_bound_p = 1/r;
01337         si->upper_bound_n = 1/r;
01338 
01339         delete[] y;
01340         delete[] zeros;
01341 }