error not zero in the extended run between 0.5 and 1. All ok for runs where extend is beyond 1

simple_extend_code/compare.py

 import dolfin as df
 import numpy as np
+np.set_printoptions(precision=16)
 
-c1File = df.XDMFFile('121223-065916_concentration.xdmf')
-c2File = df.XDMFFile('121223-065829_concentration.xdmf')
+c1File = df.XDMFFile('171223-153055_concentration.xdmf')
+c2File = df.XDMFFile('171223-153002_concentration.xdmf')
 
 mesh = df.IntervalMesh(128, -0.5, 0.5)
 times = np.arange(0.0, 1.1, 0.1)

simple_extend_code/extend_for_diffusion.py

@@ -2,6 +2,7 @@ import numpy as np
 import dolfin as df
 import progressbar
 
+np.set_printoptions(precision=16)
 df.set_log_level(df.LogLevel.ERROR)
 df.parameters['form_compiler']['optimize'] = True
 
@@ -25,6 +26,7 @@ class diffusion(object):
             self.c0.interpolate(df.Expression('1 + 0.2 * cos(pi*x[0]/L)', pi=np.pi, L=self.L, degree=1))
         else:
             self.c0 = df.project(initc, self.function_space)
+        # print('c0=', self.c0.compute_vertex_values(self.mesh))
 
     def setup_weak_forms(self):
         self.form = (df.inner((self.c - self.c0)/self.timestep, self.tc) 
@@ -36,8 +38,9 @@ class diffusion(object):
         self.cFile = df.XDMFFile('%s_concentration.xdmf' % self.timestamp)
         
         # time-variables
-        self.time = initTime
-        maxsteps = int(self.maxtime/self.timestep)
+        self.time = round(initTime, 1)
+        # print('time=', self.time)
+        maxsteps = round(self.maxtime/self.timestep)
 
         self.setup_initial_conditions(initc)
         self.setup_weak_forms()
@@ -48,8 +51,10 @@ class diffusion(object):
 
         for steps in progressbar.progressbar(range(1, maxsteps + 1)):
             self.time += self.timestep        
+            # print('time=', self.time)
             df.solve(self.form == 0, self.c)
             self.cFile.write_checkpoint(self.c, 'concentration', self.time, append=True)
+            # print('c=', self.c.compute_vertex_values(self.mesh))
             self.c0.assign(self.c)
 
         self.cFile.close()

simple_extend_code/parameters.json

@@ -5,5 +5,4 @@
     "timestep": 0.1,
     "maxtime": 1
 
-
 }   
\ No newline at end of file

simple_extend_code/run_extend_for_diffusion.py

 import json, datetime
 import os
 from extend_for_diffusion import diffusion
+from viz_extend_for_diffusion import visualize
 import argparse
 import dolfin as df
 
@@ -30,7 +31,7 @@ else:
     print('Extending run...')
     parametersFile = args.jsonfile
 
-    steps = int(parameters['maxtime']/parameters['timestep'])
+    steps = round(parameters['maxtime']/parameters['timestep'])
     
     mesh = df.IntervalMesh(parameters['resolution'], 
                             - parameters['L']/2, 
@@ -54,5 +55,4 @@ if extend:
 with open(parametersFile, "w") as jsonFile:
     json.dump(parameters, jsonFile, indent=4, sort_keys=True)
 
-from viz_extend_for_diffusion import visualize
 visualize(parameters, DIR='')

simple_extend_code/viz_extend_for_diffusion.py

@@ -6,7 +6,7 @@ import progressbar
 import matplotlib.pyplot as plt
 
 def visualize(params, DIR=''):
-    savesteps = int(params['maxtime']/params['timestep'])
+    savesteps = round(params['maxtime']/params['timestep'])
     times = np.arange(savesteps+1) * params['timestep']
     
     mesh = df.IntervalMesh(params['resolution'],