mescla.isotopes.mix_isotope¶

mescla.isotopes.mix_isotope(ratios, endmember_delta, endmember_carrier)[source]¶

Forward model: the delta of a mixture, weighted by the carrier.

\[\delta_{mix} = \frac{\sum_e f_e C_e \delta_e}{\sum_e f_e C_e}\]

Parameters:

ratios (ndarray, shape (n_samples, ne) or (ne,))
endmember_delta (ndarray, shape (ne,))
endmember_carrier (ndarray, shape (ne,)) – Carrier concentration in each end-member.

Returns:

ndarray, shape (n_samples,)

Return type:

ndarray

Examples

An equal volumetric mixture is not an equal isotopic mixture when the carrier concentrations differ – the carbon-rich end-member dominates:

>>> mix_isotope(np.array([0.5, 0.5]), np.array([-10.0, -20.0]),
...             np.array([100.0, 10.0])).round(3)
array([-10.909])