#!/usr/bin/env python
# coding: utf-8

# Intensity Weighting
# ============================
# 
# Setup
# -----------------------------

# Let's first make sure we have the latest version of PHOEBE 2.0 installed. (You can comment out this line if you don't use pip for your installation or don't want to update to the latest release).

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get_ipython().system('pip install -I "phoebe>=2.0,<2.1"')


# As always, let's do imports and initialize a logger and a new Bundle.  See [Building a System](building_a_system.html) for more details.

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get_ipython().run_line_magic('matplotlib', 'inline')


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import phoebe
from phoebe import u # units
import numpy as np
import matplotlib.pyplot as plt

logger = phoebe.logger()

b = phoebe.default_binary()


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b.add_dataset('lc', times=np.linspace(0,1,101))


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b.add_dataset('mesh', times=[0])


# Relevant Parameters 
# -------------------------------

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b['intens_weighting']


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print b['intens_weighting']


# Influence on Light Curves (fluxes)
# ---------------------------------------------
# 
# Let's (roughtly) reproduce Figure 5 from [Prsa et al. 2016](http://phoebe-project.org/publications/2016Prsa+) which shows the difference between photon and energy intensity weighting.
# 
# <img src="prsa+2016_fig5.png" alt="Figure 8" width="600px"/>

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for teff_primary in [5000,7500,10000,12500,15000]:
    b['teff@primary'] = teff_primary
    b['teff@secondary'] = 0.9 * teff_primary
    
    for weighting in ['energy', 'photon']:
        b['intens_weighting'] = weighting
        b.run_compute(irrad_method='none', model='{}_{}'.format(teff_primary, weighting))


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teff_colormap = {5000: 'm', 7500: 'r', 10000: 'g', 12500: 'c', 15000: 'b'}

fig = plt.figure()
ax1, ax2 = fig.add_subplot(211), fig.add_subplot(212)

for teff, color in teff_colormap.items():
    fluxes_energy = b.get_value('fluxes@{}_energy'.format(teff))
    fluxes_photon = b.get_value('fluxes@{}_photon'.format(teff))
    phases = b.to_phase('times@lc@dataset')
    
    # alias data from -0.6 to 0.6
    fluxes_energy = np.append(fluxes_energy, fluxes_energy[abs(phases) > 0.4])
    fluxes_photon = np.append(fluxes_photon, fluxes_photon[abs(phases) > 0.4])
    phases = np.append(phases, phases[abs(phases)>0.4]+1.0)
    phases[phases > 1.0] = phases[phases > 1.0] - 2.0
    
    sort = phases.argsort()
    phases = phases[sort]
    fluxes_energy = fluxes_energy[sort]
    fluxes_photon = fluxes_photon[sort]
    
    ax1.plot(phases, fluxes_energy, color=color)
    ax2.plot(phases, fluxes_photon-fluxes_energy, color=color)

lbl = ax1.set_xlabel('')
lbl = ax1.set_ylabel('flux')
lbl = ax2.set_xlabel('phase')
lbl = ax2.set_ylabel('flux diff')


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