"""
Examples
========
Point-to-point Mapping
----------------------
>>> import numpy as np
>>> from pymt.grids.map import RectilinearMap as Rectilinear
>>> src = Rectilinear([0, 1, 2], [0, 2])
>>> dst = Rectilinear([.5, 1.5, 2.5], [.25, 1.25])
>>> src.get_x()
array([ 0., 2., 0., 2., 0., 2.])
>>> src.get_y()
array([ 0., 0., 1., 1., 2., 2.])
>>> dst.get_x()
array([ 0.25, 1.25, 0.25, 1.25, 0.25, 1.25])
>>> dst.get_y()
array([ 0.5, 0.5, 1.5, 1.5, 2.5, 2.5])
>>> src_vals = np.arange(src.get_point_count(), dtype=np.float64)
Map the source values on the source points to the destination grid
using nearest neighbor.
>>> from pymt.mappers import NearestVal
>>> mapper = NearestVal()
>>> mapper.initialize(dst, src)
>>> mapper.run(src_vals)
array([ 0., 1., 2., 3., 4., 5.])
>>> mappers = find_mapper(dst, src)
>>> len(mappers)
3
>>> mappers[0].name
'PointToPoint'
>>> src_vals[2] = -999
>>> dst_vals = np.full(dst.get_point_count(), -1.)
>>> mapper.run(src_vals, dst_vals=dst_vals)
array([ 0., 1., -1., 3., 4., 5.])
Cell-to-point Mapping
---------------------
The source grid looks like,
::
(0) ------ (1)
| |
| |
(2) ------ (3)
| |
| |
(4) ------ (5)
| |
| |
(7) ------ (7)
>>> from pymt.mappers import CellToPoint
>>> from pymt.grids.map import UniformRectilinearMap as UniformRectilinear
>>> from pymt.grids.map import UnstructuredPointsMap as UnstructuredPoints
>>> (dst_x, dst_y) = (np.array([.45, 1.25, 3.5]), np.array([.75, 2.25, 3.25]))
>>> src = UniformRectilinear((2,4), (2, 1), (0, 0))
>>> dst = UnstructuredPoints(dst_x, dst_y)
>>> src_vals = np.arange(src.get_cell_count(), dtype=np.float64)
>>> mapper = CellToPoint()
>>> mapper.initialize(dst, src)
>>> mapper.run(src_vals, bad_val=-999)
array([ 0., 2., -999.])
>>> src_vals = np.arange(src.get_cell_count(), dtype=np.float64)
>>> src_vals[0] = -9999
>>> dst_vals = np.zeros(dst.get_point_count()) + 100
>>> _ = mapper.run(src_vals, dst_vals=dst_vals)
>>> dst_vals
array([ 100., 2., -999.])
Point-to-cell Mapping
---------------------
>>> from pymt.mappers.pointtocell import PointToCell
>>> (src_x, src_y) = (np.array ([.45, 1.25, 3.5, .0, 1.]),
... np.array ([.75, 2.25, 3.25, .9, 1.1]))
>>> src = UnstructuredPoints(src_x, src_y)
>>> dst = UniformRectilinear((2,4), (2, 1), (0, 0))
>>> src_vals = np.arange(src.get_point_count(), dtype=np.float64)
>>> mapper = PointToCell()
>>> mapper.initialize(dst, src)
>>> mapper.run(src_vals, bad_val=-999)
array([ 1.5, 4. , 1. ])
>>> mapper.run(src_vals, bad_val=-999, method=np.sum)
array([ 3., 4., 1.])
>>> src_vals[0] = -9999
>>> dst_vals = np.zeros(dst.get_cell_count ()) - 1
>>> _ = mapper.run(src_vals, dst_vals=dst_vals)
>>> dst_vals
array([-1., 4., 1.])
Point on cell edges
-------------------
>>> (src_x, src_y) = (np.array ([0, .5, 1., 2, 3.5]),
... np.array ([1., 1., .0, 3, 3.]))
>>> src = UnstructuredPoints(src_x, src_y)
>>> dst = UniformRectilinear((2,4), (2, 1), (0, 0))
>>> mapper = PointToCell()
>>> mapper.initialize(dst, src)
>>> src_vals = np.arange(src.get_point_count(), dtype=np.float64)
>>> dst_vals = np.zeros(dst.get_cell_count()) - 1
>>> _ = mapper.run(src_vals, dst_vals=dst_vals)
>>> dst_vals
array([ 1. , 0.5, 3. ])
A big mapper
============
>>> (m, n) = (20, 40)
>>> (src_x, src_y) = np.meshgrid(range(m), range(n))
>>> src = UnstructuredPoints(src_y, src_x)
>>> dst = UniformRectilinear((n + 1, m + 1), (1, 1), (-.5, -.5))
>>> mapper = PointToCell()
>>> mapper.initialize(dst, src)
>>> src_vals = np.arange(src.get_point_count(), dtype=np.float64)
>>> dst_vals = np.zeros(dst.get_cell_count(), dtype=np.float64) - 1
>>> _ = mapper.run(src_vals, dst_vals=dst_vals)
>>> from numpy.testing import assert_array_equal
>>> assert_array_equal(dst_vals, src_vals)
"""
from .celltopoint import CellToPoint
from .imapper import IncompatibleGridError
from .pointtocell import PointToCell
from .pointtopoint import NearestVal
_MAPPERS = [NearestVal, CellToPoint, PointToCell]
[docs]def find_mapper(dst_grid, src_grid):
"""Find appropriate mappers to map bewteen two grid-like objects"""
choices = []
for cls in _MAPPERS:
if cls.test(dst_grid, src_grid):
choices.append(cls())
if len(choices) == 0:
raise IncompatibleGridError(dst_grid.name, src_grid.name)
return choices
