Source code for pycalphad.core.light_dataset

"""Defines a class for internally representing arrays used in equilibrium calculations"""

import numpy as np
from xarray import Dataset


[docs]class LightDataset: """ Lightweight wrapper around an xarray Dataset. Attributes ---------- data_vars : dict coords : dict attrs : dict Notes ----- The idea of LightDataset is to provide the same constructor API as Dataset objects, but doesn't provide any `sel` or other functionality. Calls to getitem or getattr to get a DataArray from xarray Datasets can take ~1ms or more, which is problematic when the equilibrium solver operates on the order of a few tens of ms and xarray Datasets are in the core loop. This class provides a similar getattr API to accessing data variables and "wraps" xarray Datasets in the sense that any LightDataset can be converted to an xarray Dataset by the getdataset method. """ def __init__(self, data_vars=None, coords=None, attrs=None): """ Parameters ---------- data_vars : Dictionary of {Variable: (Dimensions, Values)} coords : Mapping of {Dimension: Values} attrs : Returns ------- LightDataset Notes ----- Takes on same format as xarray.Dataset initializer """ self.data_vars = data_vars or dict() self.coords = coords or dict() self.attrs = attrs or dict() for var, (coord, values) in data_vars.items(): setattr(self, var, values) for coord, values in coords.items(): setattr(self, coord, values)
[docs] def get_dataset(self): """Build an xarray Dataset""" return Dataset(self.data_vars, self.coords, self.attrs)
def __getitem__(self, item): try: return getattr(self, item) except: raise KeyError("`{}` is not a variable or coordinate".format(item))
[docs] def remove(self, item): self.data_vars.pop(item) delattr(self, item)
[docs] def merge(self, other, inplace=False, compat='no_conflicts'): if compat != 'equals': raise ValueError("Only `compat='equals'` is supported. Passed `compat={}`".format(compat)) if inplace: for var, coords_vals in other.data_vars.items(): if var not in self.data_vars.keys(): self.data_vars[var] = coords_vals setattr(self, var, coords_vals[1]) else: if np.all(self.data_vars[var] != coords_vals): raise ValueError("Cannot merge EquilibriumResults because data variable `{}` is not equal to preexisting variable".format(var)) for coord, values in other.coords.items(): if coord not in self.coords.keys(): self.coords[var] = values setattr(self, coord, values) else: if np.all(self.coords[coord] != values): raise ValueError("Cannot merge EquilibriumResults because coordinate `{}` is not equal to preexisting coordinate".format(coord)) else: raise NotImplementedError("Copy merges not implemented") return self
[docs] def add_variable(self, var, coord, value): self.data_vars[var] = (coord, value) setattr(self, var, value)