ctools

#! /usr/bin/env python

# ==========================================================================

# Display spectrum generated by csspec

#

# Copyright (C) 2015-2019 Juergen Knoedlseder

#

# This program is free software: you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation, either version 3 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program.  If not, see <http://www.gnu.org/licenses/>.

#

# ==========================================================================

import sys

try:

    import matplotlib.pyplot as plt

    plt.figure()

    plt.close()

except (ImportError, RuntimeError):

    print('This script needs the "matplotlib" module')

    sys.exit()

import gammalib

import cscripts

# ============= #

# Plot spectrum #

# ============= #

def plot_spectrum(filename, plotfile):

    """

    Plot spectrum

    Parameters

    ----------

    filename : str

        Name of spectrum FITS file

    plotfile : str

        Plot file name

    """

    # Read spectrum file    

    fits     = gammalib.GFits(filename)

    table    = fits.table(1)

    c_energy = table['Energy']

    c_ed     = table['ed_Energy']

    c_eu     = table['eu_Energy']

    c_flux   = table['Flux']

    c_eflux  = table['e_Flux']

    c_ts     = table['TS']

    c_upper  = table['UpperLimit']

    # Initialise arrays to be filled

    energies    = []

    flux        = []

    ed_engs     = []

    eu_engs     = []

    e_flux      = []

    ul_energies = []

    ul_ed_engs  = []

    ul_eu_engs  = []

    ul_flux     = []

    # Loop over rows of the file

    nrows = table.nrows()

    for row in range(nrows):

        # Get Test Statistic, flux and flux error

        ts    = c_ts.real(row)

        flx   = c_flux.real(row)

        e_flx = c_eflux.real(row)

        # If Test Statistic is larger than 9 and flux error is smaller than

        # flux then append flux plots ...

        if ts > 9.0 and e_flx < flx:

            energies.append(c_energy.real(row))

            flux.append(c_flux.real(row))

            ed_engs.append(c_ed.real(row))

            eu_engs.append(c_eu.real(row))

            e_flux.append(c_eflux.real(row))

        # ... otherwise append upper limit

        else:

            ul_energies.append(c_energy.real(row))

            ul_flux.append(c_upper.real(row))

            ul_ed_engs.append(c_ed.real(row))

            ul_eu_engs.append(c_eu.real(row))

    # Set upper limit errors

    yerr = [0.6 * x for x in ul_flux]

    # Plot the spectrum 

    plt.figure()

    plt.loglog()

    plt.grid()

    plt.errorbar(energies, flux, yerr=e_flux, xerr=[ed_engs, eu_engs],

                 fmt='ro')

    plt.errorbar(ul_energies, ul_flux, xerr=[ul_ed_engs, ul_eu_engs],

                 yerr=yerr, uplims=True, fmt='ro')

    plt.xlabel('Energy (TeV)')

    plt.ylabel(r'E$^2$ $\times$ dN/dE (erg cm$^{-2}$ s$^{-1}$)')

    # Show figure

    if len(plotfile) > 0:

        plt.savefig(plotfile)

    else:

        plt.show()

    # Return

    return

# ============= #

# Show spectrum #

# ============= #

def show_spectrum():

    """

    Show spectrum

    """

    # Set usage string

    usage = 'show_spectrum.py [-p plotfile] [file]'

    # Set default options

    options = [{'option': '-p', 'value': ''}]

    # Get arguments and options from command line arguments

    args, options = cscripts.ioutils.get_args_options(options, usage)

    # Extract script parameters from options

    plotfile = options[0]['value']

    # Show spectrum

    plot_spectrum(args[0], plotfile)

    # Return

    return

# ======================== #

# Main routine entry point #

# ======================== #

if __name__ == '__main__':

    # Show spectrum

    show_spectrum()