introduced flag do_coll_update as parameter for sweeper objects. If True (default), a proper collocation update is performed in compute_end_point. If False, the stage corresponding to the end point is copied. Throws an exception of set to False for collocation nodes where endpoint is not a stage

Author: Daniel Ruprecht

pySDC/Sweeper.py

@@ -31,7 +31,8 @@ def __init__(self,params):
 
                 defaults = dict()
                 defaults['do_LU'] = False
-
+                defaults['do_coll_update'] = True
+                
                 for k,v in defaults.items():
                     setattr(self,k,v)
 
@@ -43,6 +44,8 @@ def __init__(self,params):
 
         coll = params['collocation_class'](params['num_nodes'],0,1)
         assert isinstance(coll, CollBase)
+        if not coll.right_is_node:
+          assert self.params['do_coll_update'], "For nodes where the right end point is not a node, do_coll_update has to be set to True"
 
         # This will be set as soon as the sweeper is instantiated at the level
         self.__level = None
@@ -151,4 +154,4 @@ def update_nodes(self):
         """
         Abstract interface to node update
         """
-        return None
+        return None

pySDC/sweeper_classes/generic_LU.py

@@ -135,12 +135,17 @@ def compute_end_point(self):
         L = self.level
         P = L.prob
 
-        # start with u0 and add integral over the full interval (using coll.weights)
-        L.uend = P.dtype_u(L.u[0])
-        for m in range(self.coll.num_nodes):
-            L.uend += L.dt*self.coll.weights[m]*L.f[m+1]
-        # add up tau correction of the full interval (last entry)
-        if L.tau is not None:
-            L.uend += L.tau[-1]
-
-        return None
+-        # check if Mth node is equal to right point and do_coll_update is false, perform a simple copy
+-        if (self.coll.right_is_node and not self.params['do_coll_update']):
+-            # a copy is sufficient
+-            L.uend = P.dtype_u(L.u[-1])
+        else:
+          # start with u0 and add integral over the full interval (using coll.weights)
+          L.uend = P.dtype_u(L.u[0])
+          for m in range(self.coll.num_nodes):
+              L.uend += L.dt*self.coll.weights[m]*L.f[m+1]
+          # add up tau correction of the full interval (last entry)
+          if L.tau is not None:
+              L.uend += L.tau[-1]
+
+        return None