Fix vertex resolution in partitioner and joiner (#180)

* Set vertex resolution in partitioner/joiner to double

* Fix second occurrence in mesh joiner

Author: davidscn

src/precice-aste-join

@@ -144,6 +144,7 @@ class MeshJoiner:
         logger.info("Starting partition-wise mesh merge")
         joined_mesh = vtk.vtkUnstructuredGrid()
         joined_points = vtk.vtkPoints()
+        joined_points.SetDataTypeToDouble()
         joined_data_arrays = None
         joined_cells = vtk.vtkCellArray()
         joined_cell_types = []
@@ -231,6 +232,7 @@ class MeshJoiner:
         # Initialize Joined Mesh
         joined_mesh = vtk.vtkUnstructuredGrid()
         joined_points = vtk.vtkPoints()
+        joined_points.SetDataTypeToDouble()
         joined_points.SetNumberOfPoints(size)
         joined_data_arrays = None
         joined_cells = vtk.vtkCellArray()

src/precice-aste-partition

@@ -496,6 +496,7 @@ class MeshPartitioner:
 
         vtk_grid = vtk.vtkUnstructuredGrid()
         vtkpoints = vtk.vtkPoints()
+        vtkpoints.SetDataTypeToDouble()
         vtkpoints.SetNumberOfPoints(len(points))
         for id, point in enumerate(points):
             vtkpoints.SetPoint(id, point)