def get_diff(s1,
s2,
var,
wunit='default',
Iunit='default',
medium='default',
resample=True):
''' Get the difference between 2 spectra
Basically returns w1, I1 - I2 where (w1, I1) and (w2, I2) are the values of
s1 and s2 for variable var. (w2, I2) is linearly interpolated if needed.
Parameters
----------
s1, s2: Spectrum objects
var: str
spectral quantity (ex: 'radiance', 'transmittance'...)
wunit: 'nm', 'cm-1'
waveunit to compare in
Iunit: str
If 'default' use s1 unit for variable var
medium: 'air', 'vacuum', default'
propagating medium to compare in (if in wavelength)
Returns
-------
w1, Idiff: array
difference interpolated on the second range(order?)
See Also
--------
:func:`~radis.spectrum.compare.get_ratio`,
:func:`~radis.spectrum.compare.get_distance`,
:func:`~radis.spectrum.compare.get_residual`,
:func:`~radis.spectrum.compare.get_residual_integral`,
:func:`~radis.spectrum.compare.plot_diff`
:meth:`~radis.spectrum.spectrum.compare_with`
'''
w1, I1, w2, I2 = _get_defaults(s1,
s2,
var=var,
wunit=wunit,
Iunit=Iunit,
medium=medium,
resample=resample)
return curve_substract(w1, I1, w2,
I2) # basically w1, I1 - I2 (on same range)
def get_wdiff_Idiff():
wdiffs, Idiffs = [], []
for method in methods:
if not normalize:
if method == 'distance':
wdiff, Idiff = get_distance(s1,
s2,
var=var,
wunit=wunit,
Iunit=Iunit,
medium=medium)
elif method == 'diff':
wdiff, Idiff = get_diff(s1,
s2,
var=var,
wunit=wunit,
Iunit=Iunit,
medium=medium,
diff_window=diff_window)
elif method == 'ratio':
wdiff, Idiff = get_ratio(s1,
s2,
var=var,
wunit=wunit,
Iunit=Iunit,
medium=medium)
else:
raise ValueError(
'Unknown comparison method: {0}'.format(method))
wdiffs.append(wdiff)
Idiffs.append(Idiff)
else:
if method == 'distance':
raise ValueError(
'{0} was not implemented yet for normalized spectra'.
format(method))
elif method == 'diff':
wdiff, Idiff = curve_substract(w1, I1, w2, I2)
elif method == 'ratio':
wdiff, Idiff = get_ratio(s1,
s2,
var=var,
wunit=wunit,
Iunit=Iunit,
medium=medium)
else:
raise ValueError(
'Unknown comparison method: {0}'.format(method))
wdiffs.append(wdiff)
Idiffs.append(Idiff)
return wdiffs, Idiffs
def get_wdiff_Idiff():
wdiffs, Idiffs = [], []
for method in methods:
if not normalize:
if method == "distance":
wdiff, Idiff = get_distance(s1,
s2,
var=var,
wunit=wunit,
Iunit=Iunit)
elif method == "diff":
wdiff, Idiff = get_diff(
s1,
s2,
var=var,
wunit=wunit,
Iunit=Iunit,
diff_window=diff_window,
)
elif method == "ratio":
wdiff, Idiff = get_ratio(s1,
s2,
var=var,
wunit=wunit,
Iunit=Iunit)
else:
raise ValueError(
"Unknown comparison method: {0}".format(method))
wdiffs.append(wdiff)
Idiffs.append(Idiff)
else:
if method == "distance":
raise ValueError(
"{0} was not implemented yet for normalized spectra".
format(method))
elif method == "diff":
wdiff, Idiff = curve_substract(w1, I1, w2, I2)
elif method == "ratio":
wdiff, Idiff = get_ratio(s1,
s2,
var=var,
wunit=wunit,
Iunit=Iunit)
else:
raise ValueError(
"Unknown comparison method: {0}".format(method))
wdiffs.append(wdiff)
Idiffs.append(Idiff)
return wdiffs, Idiffs
def get_diff(s1,
s2,
var,
wunit="default",
Iunit="default",
resample=True,
diff_window=0):
# type: (Spectrum, Spectrum, str, str, str, str, bool, int) -> np.array, np.array
"""Get the difference between 2 spectra.
Basically returns w1, I1 - I2 where (w1, I1) and (w2, I2) are the values of
s1 and s2 for variable var. (w2, I2) is linearly interpolated if needed.
.. math::
dI = I_1 - I_2
Parameters
----------
s1, s2: Spectrum objects
2 spectra to compare.
var: str
spectral quantity (ex: ``'radiance'``, ``'transmittance'``...)
wunit: ``'nm'``, ``'cm-1'``, ``'nm_vac'``
waveunit to compare in: wavelength air, wavenumber, wavelength vacuum
Iunit: str
if ``'default'`` use s1 unit for variable var
medium: 'air', 'vacuum', default'
propagating medium to compare in (if in wavelength)
Other Parameters
----------------
resample: bool
if not ``True``, wavelength must be equals. Else, resample ``s2`` on
``s1`` if needed.
diff_window: int
If non 0, calculates diff by offsetting s1 by ``diff_window`` number of
units on either side, and returns the minimum. Compensates for experimental
errors on the w axis. Default 0. (look up code for more details...)
Returns
-------
w1, Idiff: array
difference interpolated on the wavespace range of the first Spectrum
Notes
-----
Uses :func:`~radis.misc.curve.curve_substract` internally
See Also
--------
:func:`~radis.spectrum.compare.get_ratio`,
:func:`~radis.spectrum.compare.get_distance`,
:func:`~radis.spectrum.compare.get_residual`,
:func:`~radis.spectrum.compare.get_residual_integral`,
:func:`~radis.spectrum.compare.plot_diff`,
:meth:`~radis.spectrum.spectrum.compare_with`
"""
w1, I1, w2, I2 = _get_defaults(s1,
s2,
var=var,
wunit=wunit,
Iunit=Iunit,
assert_same_wavelength=not resample)
# basically w1, I1 - I2 (on same range)
w1, Idiff = curve_substract(w1, I1, w2, I2)
if diff_window:
# allow fluctuation from diff_window units. Kinda compensates
# for experimental errors on x-axis
diff_list = []
I2_interp = I1 - Idiff
for i in range(-diff_window, diff_window + 1):
diff_list.append(I2_interp - np.roll(I1, i))
# get minimum in abs value
diff_list = np.array(diff_list)
b = np.abs(diff_list).argmin(axis=0)
Idiff = np.choose(b, diff_list) # keeps sign
return w1, Idiff
