Fix python wrapper (#1532)

* Fixes to the Python interface for accessing field and particle data

* In Python wrapper, cleaned up how ngrow is handled

1 files changed, 49 insertions, 48 deletions

diff --git a/Python/pywarpx/fields.py b/Python/pywarpx/fields.py
index eeed3283d..e36f4707a 100644
--- a/Python/pywarpx/fields.py
+++ b/Python/pywarpx/fields.py
@@ -45,26 +45,26 @@ class _MultiFABWrapper(object):
         self.dim = _libwarpx.dim
 
         # overlaps is one along the axes where the grid boundaries overlap the neighboring grid,
-        # which is the case with node centering
+        # which is the case with node centering.
+        # This presumably will never change during a calculation.
         self.overlaps = self.get_nodal_flag()
 
     def _getlovects(self):
         if self.direction is None:
-            lovects = self.get_lovects(self.level, self.include_ghosts)
+            lovects, ngrow = self.get_lovects(self.level, self.include_ghosts)
         else:
-            lovects = self.get_lovects(self.level, self.direction, self.include_ghosts)
-        self.nghosts = -lovects.min()
-        return lovects
+            lovects, ngrow = self.get_lovects(self.level, self.direction, self.include_ghosts)
+        return lovects, ngrow
 
     def _gethivects(self):
-        lovects = self._getlovects()
+        lovects, ngrow = self._getlovects()
         fields = self._getfields()
 
         hivects = np.zeros_like(lovects)
         for i in range(len(fields)):
             hivects[:,i] = lovects[:,i] + np.array(fields[i].shape[:self.dim]) - self.overlaps
 
-        return hivects
+        return hivects, ngrow
 
     def _getfields(self):
         if self.direction is None:
@@ -73,7 +73,8 @@ class _MultiFABWrapper(object):
             return self.get_fabs(self.level, self.direction, self.include_ghosts)
 
     def __len__(self):
-        return lend(self._getlovects())
+        lovects, ngrow = self._getlovects()
+        return lend(lovects)
 
     def mesh(self, direction):
         """Returns the mesh along the specified direction with the appropriate centering.
@@ -96,8 +97,8 @@ class _MultiFABWrapper(object):
             raise Exception('Inappropriate direction given')
 
         # --- Get the total number of cells along the direction
-        hivects = self._gethivects()
-        nn = hivects[idir,:].max() - self.nghosts + self.overlaps[idir]
+        hivects, ngrow = self._gethivects()
+        nn = hivects[idir,:].max() - ngrow[idir] + self.overlaps[idir]
         if npes > 1:
             nn = comm_world.allreduce(nn, op=mpi.MAX)
 
@@ -143,8 +144,8 @@ class _MultiFABWrapper(object):
         """Returns slices of a 3D decomposed array,
         """
 
-        lovects = self._getlovects()
-        hivects = self._gethivects()
+        lovects, ngrow = self._getlovects()
+        hivects, ngrow = self._gethivects()
         fields = self._getfields()
 
         ix = index[0]
@@ -164,9 +165,9 @@ class _MultiFABWrapper(object):
         else:
             ic = None
 
-        nx = hivects[0,:].max() - self.nghosts
-        ny = hivects[1,:].max() - self.nghosts
-        nz = hivects[2,:].max() - self.nghosts
+        nx = hivects[0,:].max() - ngrow[0]
+        ny = hivects[1,:].max() - ngrow[1]
+        nz = hivects[2,:].max() - ngrow[2]
 
         if npes > 1:
             nx = comm_world.allreduce(nx, op=mpi.MAX)
@@ -174,20 +175,20 @@ class _MultiFABWrapper(object):
             nz = comm_world.allreduce(nz, op=mpi.MAX)
 
         if isinstance(ix, slice):
-            ixstart = max(ix.start or -self.nghosts, -self.nghosts)
-            ixstop = min(ix.stop or nx + 1 + self.nghosts, nx + self.overlaps[0] + self.nghosts)
+            ixstart = max(ix.start or -ngrow[0], -ngrow[0])
+            ixstop = min(ix.stop or nx + 1 + ngrow[0], nx + self.overlaps[0] + ngrow[0])
         else:
             ixstart = ix
             ixstop = ix + 1
         if isinstance(iy, slice):
-            iystart = max(iy.start or -self.nghosts, -self.nghosts)
-            iystop = min(iy.stop or ny + 1 + self.nghosts, ny + self.overlaps[1] + self.nghosts)
+            iystart = max(iy.start or -ngrow[1], -ngrow[1])
+            iystop = min(iy.stop or ny + 1 + ngrow[1], ny + self.overlaps[1] + ngrow[1])
         else:
             iystart = iy
             iystop = iy + 1
         if isinstance(iz, slice):
-            izstart = max(iz.start or -self.nghosts, -self.nghosts)
-            izstop = min(iz.stop or nz + 1 + self.nghosts, nz + self.overlaps[2] + self.nghosts)
+            izstart = max(iz.start or -ngrow[2], -ngrow[2])
+            izstop = min(iz.stop or nz + 1 + ngrow[2], nz + self.overlaps[2] + ngrow[2])
         else:
             izstart = iz
             izstop = iz + 1
@@ -250,8 +251,8 @@ class _MultiFABWrapper(object):
         """Returns slices of a 2D decomposed array,
         """
 
-        lovects = self._getlovects()
-        hivects = self._gethivects()
+        lovects, ngrow = self._getlovects()
+        hivects, ngrow = self._gethivects()
         fields = self._getfields()
 
         ix = index[0]
@@ -270,22 +271,22 @@ class _MultiFABWrapper(object):
         else:
             ic = None
 
-        nx = hivects[0,:].max() - self.nghosts
-        nz = hivects[1,:].max() - self.nghosts
+        nx = hivects[0,:].max() - ngrow[0]
+        nz = hivects[1,:].max() - ngrow[1]
 
         if npes > 1:
             nx = comm_world.allreduce(nx, op=mpi.MAX)
             nz = comm_world.allreduce(nz, op=mpi.MAX)
 
         if isinstance(ix, slice):
-            ixstart = max(ix.start or -self.nghosts, -self.nghosts)
-            ixstop = min(ix.stop or nx + 1 + self.nghosts, nx + self.overlaps[0] + self.nghosts)
+            ixstart = max(ix.start or -ngrow[0], -ngrow[0])
+            ixstop = min(ix.stop or nx + 1 + ngrow[0], nx + self.overlaps[0] + ngrow[0])
         else:
             ixstart = ix
             ixstop = ix + 1
         if isinstance(iz, slice):
-            izstart = max(iz.start or -self.nghosts, -self.nghosts)
-            izstop = min(iz.stop or nz + 1 + self.nghosts, nz + self.overlaps[1] + self.nghosts)
+            izstart = max(iz.start or -ngrow[1], -ngrow[1])
+            izstop = min(iz.stop or nz + 1 + ngrow[1], nz + self.overlaps[1] + ngrow[1])
         else:
             izstart = iz
             izstop = iz + 1
@@ -365,8 +366,8 @@ class _MultiFABWrapper(object):
         iy = index[1]
         iz = index[2]
 
-        lovects = self._getlovects()
-        hivects = self._gethivects()
+        lovects, ngrow = self._getlovects()
+        hivects, ngrow = self._gethivects()
         fields = self._getfields()
 
         if len(index) > self.dim:
@@ -377,9 +378,9 @@ class _MultiFABWrapper(object):
         else:
             ic = None
 
-        nx = hivects[0,:].max() - self.nghosts
-        ny = hivects[1,:].max() - self.nghosts
-        nz = hivects[2,:].max() - self.nghosts
+        nx = hivects[0,:].max() - ngrow[0]
+        ny = hivects[1,:].max() - ngrow[1]
+        nz = hivects[2,:].max() - ngrow[2]
 
         # --- Add extra dimensions so that the input has the same number of
         # --- dimensions as array.
@@ -392,20 +393,20 @@ class _MultiFABWrapper(object):
             value3d.shape = sss
 
         if isinstance(ix, slice):
-            ixstart = max(ix.start or -self.nghosts, -self.nghosts)
-            ixstop = min(ix.stop or nx + 1 + self.nghosts, nx + self.overlaps[0] + self.nghosts)
+            ixstart = max(ix.start or -ngrow[0], -ngrow[0])
+            ixstop = min(ix.stop or nx + 1 + ngrow[0], nx + self.overlaps[0] + ngrow[0])
         else:
             ixstart = ix
             ixstop = ix + 1
         if isinstance(iy, slice):
-            iystart = max(iy.start or -self.nghosts, -self.nghosts)
-            iystop = min(iy.stop or ny + 1 + self.nghosts, ny + self.overlaps[1] + self.nghosts)
+            iystart = max(iy.start or -ngrow[1], -ngrow[1])
+            iystop = min(iy.stop or ny + 1 + ngrow[1], ny + self.overlaps[1] + ngrow[1])
         else:
             iystart = iy
             iystop = iy + 1
         if isinstance(iz, slice):
-            izstart = max(iz.start or -self.nghosts, -self.nghosts)
-            izstop = min(iz.stop or nz + 1 + self.nghosts, nz + self.overlaps[2] + self.nghosts)
+            izstart = max(iz.start or -ngrow[2], -ngrow[2])
+            izstop = min(iz.stop or nz + 1 + ngrow[2], nz + self.overlaps[2] + ngrow[2])
         else:
             izstart = iz
             izstop = iz + 1
@@ -442,8 +443,8 @@ class _MultiFABWrapper(object):
         ix = index[0]
         iz = index[2]
 
-        lovects = self._getlovects()
-        hivects = self._gethivects()
+        lovects, ngrow = self._getlovects()
+        hivects, ngrow = self._gethivects()
         fields = self._getfields()
 
         if len(fields[0].shape) > self.dim:
@@ -459,8 +460,8 @@ class _MultiFABWrapper(object):
         else:
             ic = None
 
-        nx = hivects[0,:].max() - self.nghosts
-        nz = hivects[2,:].max() - self.nghosts
+        nx = hivects[0,:].max() - ngrow[0]
+        nz = hivects[2,:].max() - ngrow[1]
 
         # --- Add extra dimensions so that the input has the same number of
         # --- dimensions as array.
@@ -472,14 +473,14 @@ class _MultiFABWrapper(object):
             value3d.shape = sss
 
         if isinstance(ix, slice):
-            ixstart = max(ix.start or -self.nghosts, -self.nghosts)
-            ixstop = min(ix.stop or nx + 1 + self.nghosts, nx + self.overlaps[0] + self.nghosts)
+            ixstart = max(ix.start or -ngrow[0], -ngrow[0])
+            ixstop = min(ix.stop or nx + 1 + ngrow[0], nx + self.overlaps[0] + ngrow[0])
         else:
             ixstart = ix
             ixstop = ix + 1
         if isinstance(iz, slice):
-            izstart = max(iz.start or -self.nghosts, -self.nghosts)
-            izstop = min(iz.stop or nz + 1 + self.nghosts, nz + self.overlaps[2] + self.nghosts)
+            izstart = max(iz.start or -ngrow[1], -ngrow[1])
+            izstop = min(iz.stop or nz + 1 + ngrow[1], nz + self.overlaps[2] + ngrow[1])
         else:
             izstart = iz
             izstop = iz + 1