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106 lines
3.9 KiB
Python
106 lines
3.9 KiB
Python
"""
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Position-related methods for Grid class
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"""
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from typing import List
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import numpy
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from numpy import zeros
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from . import GridError
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def ind2pos(self,
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ind: numpy.ndarray or List,
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which_shifts: int = None,
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round_ind: bool = True,
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check_bounds: bool = True
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) -> numpy.ndarray:
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"""
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Returns the natural position corresponding to the specified cell center indices.
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The resulting position is clipped to the bounds of the grid
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(to cell centers if round_ind=True, or cell outer edges if round_ind=False)
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:param ind: Indices of the position. Can be fractional. (3-element ndarray or list)
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:param which_shifts: which grid number (shifts) to use
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:param round_ind: Whether to round ind to the nearest integer position before indexing
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(default True)
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:param check_bounds: Whether to raise an GridError if the provided ind is outside of
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the grid, as defined above (centers if round_ind, else edges) (default True)
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:return: 3-element ndarray specifying the natural position
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:raises: GridError
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"""
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if which_shifts is not None and which_shifts >= self.shifts.shape[0]:
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raise GridError('Invalid shifts')
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ind = numpy.array(ind, dtype=float)
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if check_bounds:
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if round_ind:
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low_bound = 0.0
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high_bound = -1
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else:
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low_bound = -0.5
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high_bound = -0.5
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if (ind < low_bound).any() or (ind > self.shape - high_bound).any():
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raise GridError('Position outside of grid: {}'.format(ind))
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if round_ind:
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rind = numpy.clip(numpy.round(ind).astype(int), 0, self.shape - 1)
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sxyz = self.shifted_xyz(which_shifts)
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position = [sxyz[a][rind[a]].astype(int) for a in range(3)]
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else:
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sexyz = self.shifted_exyz(which_shifts)
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position = [numpy.interp(ind[a], numpy.arange(sexyz[a].size) - 0.5, sexyz[a])
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for a in range(3)]
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return numpy.array(position, dtype=float)
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def pos2ind(self,
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r: numpy.ndarray or List,
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which_shifts: int or None,
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round_ind: bool=True,
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check_bounds: bool=True
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) -> numpy.ndarray:
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"""
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Returns the cell-center indices corresponding to the specified natural position.
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The resulting position is clipped to within the outer centers of the grid.
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:param r: Natural position that we will convert into indices (3-element ndarray or list)
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:param which_shifts: which grid number (shifts) to use
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:param round_ind: Whether to round the returned indices to the nearest integers.
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:param check_bounds: Whether to throw an GridError if r is outside the grid edges
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:return: 3-element ndarray specifying the indices
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:raises: GridError
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"""
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r = numpy.squeeze(r)
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if r.size != 3:
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raise GridError('r must be 3-element vector: {}'.format(r))
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if (which_shifts is not None) and (which_shifts >= self.shifts.shape[0]):
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raise GridError('Invalid which_shifts: {}'.format(which_shifts))
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sexyz = self.shifted_exyz(which_shifts)
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if check_bounds:
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for a in range(3):
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if self.shape[a] > 1 and (r[a] < sexyz[a][0] or r[a] > sexyz[a][-1]):
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raise GridError('Position[{}] outside of grid!'.format(a))
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grid_pos = zeros((3,))
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for a in range(3):
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xi = numpy.digitize(r[a], sexyz[a]) - 1 # Figure out which cell we're in
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xi_clipped = numpy.clip(xi, 0, sexyz[a].size - 2) # Clip back into grid bounds
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# No need to interpolate if round_ind is true or we were outside the grid
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if round_ind or xi != xi_clipped:
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grid_pos[a] = xi_clipped
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else:
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# Interpolate
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x = self.shifted_xyz(which_shifts)[a][xi]
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dx = self.shifted_dxyz(which_shifts)[a][xi]
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f = (r[a] - x) / dx
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# Clip to centers
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grid_pos[a] = numpy.clip(xi + f, 0, self.shape[a] - 1)
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return grid_pos
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