class RegularGrid(Grid):
def __init__(self,grid_desc):
assert isinstance(grid_desc,(list,tuple))
for gd in grid_desc:
assert isinstance(gd,(list,tuple))
assert 3 == len(gd)
self.dim = len(grid_desc)
self.grid_desc = grid_desc # List of (low,high,num) triples
(low,hi,num_cells) = zip(*self.grid_desc)
self.lower_bound = np.array(low,dtype=np.double)
self.upper_bound = np.array(hi,dtype=np.double)
self.num_cells = np.array(num_cells,dtype=np.integer)
assert not np.any(self.num_cells <= 0)
self.num_nodes = self.num_cells + 1
# Cell dimensions
self.delta = (self.upper_bound - self.lower_bound)
self.delta /= self.num_cells.astype(np.double)
# Initialize the indexer
self.cell_indexer = Indexer(self.num_cells)
self.node_indexer = Indexer(self.num_nodes)
# Fuzz to convert [low,high) to [low,high]
self.fuzz = 1e-15
def points_to_cell_coords(self,points):
"""
Figure out where points are. Returns the cell coordinate.
"""
assert is_mat(points)
(N,D) = points.shape
assert D == self.dim
# Get the OOB info
oob = OutOfBounds()
oob.build_from_points(self,points)
assert oob.check()
raw_coords = np.empty((N,D))
for d in xrange(D):
(low,high,num_cells) = self.grid_desc[d]
# Transform: [low,high) |-> [0,n)
transform = num_cells * (points[:,d] - low) / (high - low)
transform += self.fuzz
raw_coords[:,d] = np.floor(transform).astype(np.integer)
# Add a little fuzz to make sure stuff on the boundary is
# mapped correctly
# Fuzz top boundary to get [low,high]
fuzz_mask = np.logical_and(high <= points[:,d],
points[:,d] < high + 2*self.fuzz)
raw_coords[fuzz_mask,d] = num_cells - 1
# Counts things just a littttle bit greater than last cell
# boundary as part of the last cell
raw_coords[oob.mask,:] = np.nan
assert is_int(raw_coords)
coords = Coordinates(raw_coords,oob)
assert coords.check()
return coords
def points_to_cell_indices(self,points):
assert is_mat(points)
(N,D) = points.shape
cell_coords = self.points_to_cell_coords(points)
assert isinstance(cell_coords,Coordinates)
assert (N,D) == cell_coords.shape
cell_indices = self.cell_indexer.coords_to_indices(cell_coords)
assert is_vect(cell_indices)
assert (N,) == cell_indices.shape
return cell_indices
def cell_indices_to_cell_coords(self,cell_indices):
cell_coords = self.cell_indexer.indices_to_coords(cell_indices)
return cell_coords
def cell_indices_to_mid_points(self,cell_indices):
assert is_vect(cell_indices)
low_points = cell_indices_to_low_points(self,cell_indices)
mid_points = low_points + row_vect(0.5 * self.delta)
assert is_mat(mid_points)
assert mid_points.shape[0] == cell_indices.shape[0]
return mid_points
def cell_indices_to_low_points(self,cell_indices):
assert is_vect(cell_indices)
cell_coords = self.cell_indexer.indices_to_coords(cell_indices)
assert isinstance(cell_coords,Coordinates)
assert cell_coords.check()
low_points = self.cell_coords_to_low_points(cell_coords)
assert is_mat(low_points)
assert cell_coords.shape == low_points.shape
return low_points
def cell_coords_to_low_points(self,cell_coords):
assert isinstance(cell_coords,Coordinates)
assert self.dim == cell_coords.dim
assert cell_coords.check()
C = cell_coords.coords
oob = cell_coords.oob
assert np.all(np.isnan(C[oob.mask,:]))
low_points = row_vect(self.lower_bound) + C * row_vect(self.delta)
assert is_mat(low_points)
assert np.all(np.isnan(low_points[oob.mask,:]))
assert cell_coords.shape == low_points.shape
return low_points
def node_indices_to_node_points(self,node_indices):
assert is_vect(node_indices)
(N,) = node_indices.shape
node_coords = self.node_indexer.indices_to_coords(node_indices)
assert isinstance(node_coords,Coordinates)
oob = node_coords.oob
C = node_coords.coords
assert np.all(np.isnan(C[oob.mask,:]))
node_points = row_vect(self.lower_bound) + C * row_vect(self.delta)
assert is_mat(node_points)
assert np.all(np.isnan(node_points[oob.mask,:]))
assert node_coords.shape == node_points.shape
return node_points
def cell_indices_to_vertex_indices(self,cell_indices):
assert is_vect(cell_indices)
cell_coords = self.cell_indexer.indices_to_coords(cell_indices)
assert isinstance(cell_coords,Coordinates)
vertex_indices = self.cell_coords_to_vertex_indices(cell_coords)
assert is_mat(vertex_indices) # (N x 2**D) matrix
return vertex_indices
def cell_coords_to_vertex_indices(self,cell_coords):
assert isinstance(cell_coords,Coordinates)
(N,D) = cell_coords.shape
assert self.dim == D
"""
The low node index in the cell has the same coords in node-land
as the cell in cell-land:
| |
-o - o-
| x |
-x - o-
| |
"""
low_vertex = self.node_indexer.coords_to_indices(cell_coords)
# Array of index offsets to reach every vertex in cell
shift = self.node_indexer.cell_shift()
assert (2**D,) == shift.shape
vertices = col_vect(low_vertex) + row_vect(shift)
assert (N,2**D) == vertices.shape
"""
Handle out of bound nodes. There is a constant offset for
converting cell oob indices to node oob indices.
Also the difference between max spatial indices.
"""
oob = cell_coords.oob
if oob.has_oob():
# Figure out the right oob node
oob_indices = cell_coords.oob.indices[oob.mask]
offset = self.node_indexer.get_num_spatial_nodes()
vertices[oob.mask,0] = oob_indices + offset
vertices[oob.mask,1:] = np.nan
return vertices
def points_to_low_vertex_rel_distance(self,points,cell_coords):
assert is_mat(points)
assert isinstance(cell_coords,Coordinates)
(N,D) = points.shape
assert (N,D) == cell_coords.shape
low_vertex = self.cell_coords_to_low_points(cell_coords)
dist = np.empty((N,D))
for d in xrange(D):
dist[:,d] = (points[:,d] - low_vertex[:,d]) / self.delta[d]
# OOB -> 0 distance from OOB node
dist[cell_coords.oob.mask,:] = 0.0
assert np.all(dist >= 0.0)
assert np.all(dist <= 1.0)
return dist
def are_points_oob(self,points):
"""
Check if points are out-of-bounds
"""
(N,D) = points.shape
assert D == self.dim
L = np.any(points < row_vect(self.lower_bound),axis=1)
U = np.any(points > row_vect(self.upper_bound) + self.fuzz,axis=1)
assert (N,) == L.shape
assert (N,) == U.shape
return np.logical_or(L,U)
