bugfix for Q transfer (this fixes #92)

Author: pancetta

pySDC/core/BaseTransfer.py

@@ -33,7 +33,7 @@ def __init__(self, fine_level, coarse_level, base_transfer_params, space_transfe
         class __Pars(FrozenClass):
             def __init__(self, pars):
                 self.finter = False
-                self.coll_iorder = 1
+                self.coll_iorder = 2
                 self.coll_rorder = 1
                 for k, v in pars.items():
                     setattr(self, k, v)
@@ -110,8 +110,7 @@ def restrict(self):
             tmp_u.append(self.space_transfer.restrict(F.u[m]))
 
         # restrict collocation values
-        G.u[0] = tmp_u[0]
-        for n in range(1, SG.coll.num_nodes + 1):
+        for n in range(0, SG.coll.num_nodes + 1):
             G.u[n] = self.Rcoll[n, 0] * tmp_u[0]
             for m in range(1, SF.coll.num_nodes + 1):
                 G.u[n] += self.Rcoll[n, m] * tmp_u[m]
@@ -133,11 +132,11 @@ def restrict(self):
             tmp_tau.append(self.space_transfer.restrict(tauF[m]))
 
         # restrict fine level tau correction part in collocation
-        tauFG = [tmp_tau[0]]
-        for n in range(1, SG.coll.num_nodes):
-            tauFG.append(self.Rcoll[n + 1, 1] * tmp_tau[0])
+        tauFG = []
+        for n in range(1, SG.coll.num_nodes + 1):
+            tauFG.append(self.Rcoll[n, 1] * tmp_tau[0])
             for m in range(1, SF.coll.num_nodes):
-                tauFG[-1] += self.Rcoll[n + 1, m + 1] * tmp_tau[m]
+                tauFG[-1] += self.Rcoll[n, m + 1] * tmp_tau[m]
 
         # build tau correction
         for m in range(SG.coll.num_nodes):
@@ -150,10 +149,10 @@ def restrict(self):
                 tmp_tau.append(self.space_transfer.restrict(F.tau[m]))
 
             # restrict possible tau correction from fine in collocation
-            for n in range(0, SG.coll.num_nodes):
-                G.tau[n] += self.Rcoll[n + 1, 1] * tmp_tau[0]
+            for n in range(1, SG.coll.num_nodes + 1):
+                G.tau[n - 1] += self.Rcoll[n, 1] * tmp_tau[0]
                 for m in range(1, SF.coll.num_nodes):
-                    G.tau[n] += self.Rcoll[n + 1, m + 1] * tmp_tau[m]
+                    G.tau[n - 1] += self.Rcoll[n, m + 1] * tmp_tau[m]
         else:
             pass
 
@@ -201,8 +200,7 @@ def prolong(self):
             tmp_u.append(self.space_transfer.prolong(G.u[m] - G.uold[m]))
 
         # interpolate values in collocation
-        F.u[0] += tmp_u[0]
-        for n in range(1, SF.coll.num_nodes + 1):
+        for n in range(0, SF.coll.num_nodes + 1):
             for m in range(0, SG.coll.num_nodes + 1):
                 F.u[n] += self.Pcoll[n, m] * tmp_u[m]
 
@@ -247,9 +245,7 @@ def prolong_f(self):
             tmp_f.append(self.space_transfer.prolong(G.f[m] - G.fold[m]))
 
         # interpolate values in collocation
-        F.u[0] += tmp_u[0]
-        F.f[0] += tmp_f[0]
-        for n in range(1, SF.coll.num_nodes + 1):
+        for n in range(0, SF.coll.num_nodes + 1):
             for m in range(0, SG.coll.num_nodes + 1):
                 F.u[n] += self.Pcoll[n, m] * tmp_u[m]
                 F.f[n] += self.Pcoll[n, m] * tmp_f[m]

tests/test_Q_transfer.py

@@ -109,8 +109,6 @@ def check_Q_transfer_minimal(collclass):
             err_inter = np.linalg.norm(uinter-ufine, np.inf)
             err_restr = np.linalg.norm(urestr-ucoarse, np.inf)
 
-            print(M, Mcoarse, 2, err_inter)
-
             if polyorder <= 2:
                 assert err_inter < 2E-15, "ERROR: Q-interpolation order is not reached, got %s" %err_inter
                 assert err_restr < 2E-15, "ERROR: Q-restriction order is not reached, got %s" % err_restr