"""
Simplified Interpolating.
Uses scipy.interpolate.
"""
import warnings
import numpy as np
import uncertainties as unc
import uncertainties.unumpy as unp
from scipy import interpolate as interp
from scipy.interpolate import bisplev, bisplrep
# from smpl import plot as splot
from smpl import data, doc
from smpl.doc import append_doc, append_str
unv = unp.nominal_values
usd = unp.std_devs
# mimick removed interp2d from scipy
# https://scipy.github.io/devdocs/tutorial/interpolate/interp_transition_guide.html
[docs]
def interp_interp2d(xxr, yyr, zzr, kind="linear"):
kx = 1
ky = 1
if kind == "linear":
kx = 1
ky = 1
elif kind == "cubic":
kx = 3
ky = 3
else:
raise ValueError("kind must be 'linear' or 'cubic'")
tck = bisplrep(xxr, yyr, zzr, kx=kx, ky=ky)
return lambda x, y: bisplev(x, y, tck).T
[docs]
def identity(x):
return x
default = {
"interpolator": [
"cubic",
"Use 'cubic' (spline) or 'linear' (cf. <https://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.interp1d.html#scipy.interpolate.interp1d>).",
],
"order": [3, "Spline order."],
"pre": [identity, "pre interpolation"],
"post": [identity, "post interpolation"],
"interpolate_upper_uncertainty": [
True,
"Interpolate only using upper uncertainty.",
],
"interpolate_lower_uncertainty": [
True,
"Interpolate only using lower uncertainty.",
],
}
# @doc.insert_str("\tDefault kwargs\n\n\t")
[docs]
@append_doc(data.data_kwargs)
@append_str("\t")
@append_str(doc.array_table(default, init=False))
@append_str(
doc.array_table({"interpolate_kwargs": ["default", "description"]}, bottom=False)
)
def interpolate_kwargs(kwargs):
"""Set default interpolate_kwargs if not set."""
kwargs = data.data_kwargs(kwargs)
for k, v in default.items():
if k not in kwargs:
kwargs[k] = v[0]
return kwargs
[docs]
def interpolate_split(datax, datay, **kwargs):
"""
Splits datax and datay into (x,y,xerr,yerr).
Parameters
----------
**kwargs : optional
see :func:`interpolate_kwargs`.
"""
kwargs = interpolate_kwargs(kwargs)
return data.filtered_data_split(datax, datay, **kwargs)
[docs]
def interpolate(*data, **kwargs):
# TODO save spl_upd spl_down values instead of recalculate
# TODO set eps
kwargs = interpolate_kwargs(kwargs)
kwargs["sortbyx"] = False
_, y, _, dy = interpolate_split(data[0], data[-1], **kwargs)
ret = None
if dy is None:
spl_center = _interpolate(*data[:-1], (y), **kwargs)
ret = np.vectorize(spl_center, otypes=["float"])
elif (
kwargs["interpolate_upper_uncertainty"]
and kwargs["interpolate_lower_uncertainty"]
):
spl_up = _interpolate(*data[:-1], (y + dy), **kwargs)
spl_down = _interpolate(*data[:-1], (y - dy), **kwargs)
ret = np.vectorize(
lambda *a: unc.ufloat(
spl_up(*a) / 2 + spl_down(*a) / 2,
np.abs(spl_up(*a) - spl_down(*a)) / 2,
),
otypes=["object"],
) # symmetrized error...
# return np.vectorize(Bounds(spl_up, spl_down), otypes=["object"])
elif not kwargs["interpolate_lower_uncertainty"]:
spl_center = _interpolate(*data[:-1], (y), **kwargs)
spl_up = _interpolate(*data[:-1], (y + dy), **kwargs)
ret = np.vectorize(
lambda *a: unc.ufloat(spl_center(*a), np.abs(spl_up(*a) - spl_center(*a))),
otypes=["object"],
) # symmetrized error...
elif not kwargs["interpolate_upper_uncertainty"]:
spl_center = _interpolate(*data[:-1], (y), **kwargs)
spl_down = _interpolate(*data[:-1], (y - dy), **kwargs)
ret = np.vectorize(
lambda *a: unc.ufloat(
spl_center(*a), np.abs(spl_down(*a) - spl_center(*a))
),
otypes=["object"],
) # symmetrized error...
else:
raise ValueError(
"interpolate_upper_uncertainty and interpolate_lower_uncertainty can't be both False"
)
if not check(ret, *data):
warnings.warn("Bad interpolation. Increase Order or symmetrize error.")
return ret
[docs]
def check(f, *args):
return np.all(np.isclose(unv(f(*args[:-1])), unv(args[-1]), rtol=1e-2))
def _interpolate(*data, **kwargs):
ret = None
datay = kwargs["pre"](data[-1])
if len(data) == 2:
if kwargs["interpolator"] == "exp":
ret = _interpolate_exp(*data[:-1], datay)
else:
ret = interp.interp1d(*data[:-1], datay, kind=kwargs["interpolator"])
elif len(data) == 3:
if kwargs["interpolator"] == "bivariatespline":
ret = interp.SmoothBivariateSpline(
*data[:-1], datay, kx=kwargs["order"], ky=kwargs["order"]
)
elif kwargs["interpolator"] == "linearnd":
ret = interp.LinearNDInterpolator(list(zip(*data[:-1])), datay)
else:
ret = interp_interp2d(*data[:-1], datay, kind=kwargs["interpolator"])
elif kwargs["interpolator"] == "linear":
ret = interp.LinearNDInterpolator(list(zip(*data[:-1])), datay)
# return np.vectorize(Post(ret, kwargs['post']), otypes=["object"])
return np.vectorize(lambda *a: kwargs["post"](ret(*a)), otypes=["object"])
def _interpolate_exp(x, y, **kwargs):
ip = interp.interp1d(x, np.log(y), kind="linear")
return lambda x_new: np.exp(ip(x_new))