__init__.py

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## @file __init__.py Loader of libswarmng_ext and root of the @ref swarmng package.
#
# To read the documentation generated from this file refer to @ref swarmng

## @package swarmng
#  Python interface to the Swarm-NG library
#
#  This package loads and verifies the libswarmng_ext.so and
#  adds some API that is implemented in Python. 
#
#  The extensive module for opening log files is also included in \ref swarmng.logdb
#  

import sys
import os
import imp
from ctypes import CDLL, c_char_p
import platform

# First find the source directory of Swarm
SWARMDIR = os.path.dirname(os.path.dirname(os.path.dirname(os.path.realpath(__file__))))

# We have some guesses as where to find the library
DEFAULT_PLACES = [ 'lib', os.path.join(SWARMDIR,'build/lib'), os.path.join(SWARMDIR,'lib') ]

# Find and load the so library
_, fn, _ = imp.find_module('libswarmng_ext', sys.path + DEFAULT_PLACES)
so_dll = CDLL(fn)

# Get the functions that allow you to read the Python versions
so_hexversion = so_dll.python_hexversion
so_version    = so_dll.python_version
so_version.restype = c_char_p

# Test the Python version
if so_hexversion() != sys.hexversion :
  print("The swarmng library was build for Python version %s, but you are running %s" % (so_version(), platform.python_version()))
  sys.exit(1)
else:
  imp.load_dynamic('libswarmng_ext', fn)

from libswarmng_ext import *
from collections import namedtuple




## Convert hashes and keyword arguments to a @ref swarmng.Config object
#
#
#  There are three ways to use this function:
#  # Combining one or more hashes into a @ref swarmng.Config object
#  @code{.py}
#  >>> cc = { 'nsys' : 16, 'nbod' : 3 }
#  >>> c1 = { 'integrator' : 'hermite_cpu' , 'time_step' : 0.001, 'log_writer' : 'bdb' }
#  >>> swarmng.config(c1)
#  >>> swarmng.config(c1, c2)
#  @endcode
#  # Create a config object for inline use using keyword arguments. Following snippet initializes Swarm with `nogpu = 1`
#  @code{.py}
#  >>> c = swarmng.config(nogpu = 1)
#  >>> swarmng.init(c) 
#  @endcode
#  # Combine hashes and keyword arguments.
#  @code{.py}
#  >>> c1 = { 'integrator' : 'hermite_cpu' , 'time_step' : 0.001, 'log_writer' : 'bdb' }
#  >>> swarmng.config(c1, { 'nsys' : 16, 'nbod' : 3 } , nogpu = 1)
#  @endcode
#
#  Arguments and return type:
#  @arg arbitrary number of Hash objects and keyword arguments
#
#  Returns: a @ref swarmng.Config object that combines configuration options
#  from the hashes and keyword arguments.
def config(*l,**kw):
    c = Config()
    def addHash(h):
        for k,v in h.items():
            c[k] = str(v)

    for h in l:
        addHash(h)
    addHash(kw)
    return c

KeplerianCoordinates = namedtuple('KeplerianCoordinates',
    ['a', 'e', 'i', 'O', 'w', 'M' ])


## Caluclate Keplerian coordinates for a planet with respect to a predefined center
#  
#  \arg \c planet : a tuple of structure ((x,y,z),(vx,vy,vz),mass)
#  \arg \c center : the supposed center of the orbit that planet is orbiting ( around of structure ((x,y,z),(vx,vy,vz),mass) )
#
#  \ret Return type: a named tuple that has the following attributes
#  * a : semi-major axis
#  * e : eccentricity
#  * i : inclination
#  * O : Longitude of the ascending node
#  * w : Argument of periapsis
#  * M : mean anomaly.
#
#  Refer to <a href="https://en.wikipedia.org/wiki/Orbital_elements">Wikipedia:Orbital elements</a> for meaning of these.
#
def keplerian_for_cartesian(planet,center):
    ((x,y,z),(vx,vy,vz),mass) = planet
    ((cx,cy,cz),(cvx,cvy,cvz),cmass) = center
    (a,e,i,O,w,M) =  calc_keplerian_for_cartesian(x-cx,y-cy,z-cz, vx-cvx,vy-cvy,vz-cvz, mass + cmass)
    return KeplerianCoordinates(a,e,i,O,w,M)



def mkConfig(h):
  return config(h)