Add new function GivensFGFT::compute_fourier() to return the fourier matrix approximate.

misc/test/src/C++/GivensFGFT.cpp.in

@@ -67,8 +67,19 @@ int main()
 	Faust::MatDense<FPP,Cpu> full_D = Faust::MatDense<FPP,Cpu>(D);
 	cout << "D fro norm:" << D.norm() << endl;
 
+	Faust::MatDense<FPP,Cpu> fourier_diag2 = algo.compute_fourier();
+	Faust::MatDense<FPP,Cpu> ordered_fourier_diag2 = algo.compute_fourier(true);
+
 	Faust::MatDense<FPP,Cpu> * ordered_fourier_diag = fourier_diag.get_cols(algo.get_ord_indices());
 
+	fourier_diag2 -= fourier_diag;
+	ordered_fourier_diag2 -= *ordered_fourier_diag;
+	cout << "norm(fourier_diag2-fourier_diag): " << fourier_diag2.norm() << endl;
+	cout << "norm(ordered_fourier_diag2-ordered_fourier_diag): " << ordered_fourier_diag2.norm() << endl;
+
+	//verify approx. fourier is properly computed (when ordered or not)
+	assert(fourier_diag2.norm()==0);
+	assert(ordered_fourier_diag2.norm()==0);
 
 	Faust::MatDense<FPP,Cpu> ordered_D(algo.get_D(true));
 
@@ -82,7 +93,7 @@ int main()
 		cout << ordered_D.getData()[i*ordered_D.getNbRow()+i] << " " << full_D(i,i) << endl;
 	}
 
-	cout << "orderded fourier_diag fro norm: " << ordered_fourier_diag->norm() << endl;
+	cout << "ordered fourier_diag fro norm: " << ordered_fourier_diag->norm() << endl;
 	cout << "Lap fro norm: " << Lap.norm() << endl;
 
 	Faust::MatDense<FPP,Cpu> tmp = *ordered_fourier_diag;

src/algorithm/factorization/faust_GivensFGFT.h

@@ -123,6 +123,12 @@ namespace Faust {
 			 */
 			const MatSparse<FPP,DEVICE> get_D(const bool ord=false);
 
+			/**
+			 *
+			 *
+			 */
+			const MatDense<FPP,DEVICE> compute_fourier(const bool ord=false);
+
 			/**
 			 *
 			 */

src/algorithm/factorization/faust_GivensFGFT.hpp

@@ -334,6 +334,26 @@ const Faust::MatSparse<FPP,DEVICE> GivensFGFT<FPP,DEVICE,FPP2>::get_D(const bool
 	return D;
 }
 
+template<typename FPP, Device DEVICE, typename FPP2>
+const Faust::MatDense<FPP,DEVICE> GivensFGFT<FPP,DEVICE,FPP2>::compute_fourier(const bool ord /* default to false */)
+{
+	Faust::MatDense<FPP,Cpu> fourier(Lap.getNbRow(), Lap.getNbCol());
+	Faust::MatDense<FPP,Cpu>* ord_fourier;
+	fourier.setEyes();
+	for(int i=facts.size()-1;i>=0;i--)
+		facts[i].multiply(fourier, 'N');
+	if(ord)
+	{
+		if(!is_D_ordered)
+			order_D();
+		ord_fourier = fourier.get_cols(ord_indices);
+		fourier = *ord_fourier;
+		delete ord_fourier;
+	}
+	return fourier;
+}
+
+
 template<typename FPP, Device DEVICE, typename FPP2>
 const MatDense<FPP,DEVICE>& GivensFGFT<FPP,DEVICE,FPP2>::get_L() const
 {