CODEWITHSUNDEEP
pythonpython-2.7python-3.xnumpyscipy
Dalek
Dalek

Reputation: 4318

Defining numpy.array in the __init__ function of a class

I am not very familiar with writing classes in python, I am trying to modify one written class for my application. the problem is that I want to give halo_pos parameter as an input to the following NFW class: 

class NFW(object):
    _req_params = { 'mass' : float , 'conc' : float , 'redshift' : float }
    _opt_params = { 'halo_pos' :[float,float]  , 'omega_m' : float , 'omega_lam' : float }
    _single_params = []
    _takes_rng = False
    _takes_logger = False

    def __init__(self, mass, conc, redshift, halo_pos, 
                 omega_m=None, omega_lam=None, cosmo=None):
        self.M = float(mass)
        self.c = float(conc)
        self.z = float(redshift)
        self.halo_pos.x = float(halo_pos[0])
        self.halo_pos.y = float(halo_pos[1])  
        self.cosmo = cosmo

if I pass the input for halo_pos for the following parameters

>>> Xpos.value
array(235.0)
>>> type(Xpos.value)
<type 'numpy.ndarray'>
>>> Ypos.value
array(340.0)
omega_matter=0.23;omega_lambda=0.77

then when I try to call NFW class with the given inputs I get the following error message:

nfw = nfw_halo.NFWHalo(mass=M,conc=concentration,redshift=z_halo,halo_pos=[Xpos,Ypos],omega_m=omega_matter,omega_lam=omega_lambda)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "nfw_halo.py", line 156, in __init__
    self.halo_pos.x = float(halo_pos[0])
AttributeError: 'NFWHalo' object has no attribute 'halo_pos'

How should I define halo_pos for my class in order to avoid raise error message?

Upvotes: 0

Views: 3585

Answers (1)

Zifendale
Zifendale

Reputation: 140

You're not declaring the halo_pos variable that you're assigning in your init section.

class NFW(object):
    _req_params = { 'mass' : float , 'conc' : float , 'redshift' : float }
    _opt_params = { 'halo_pos' :[float,float]  , 'omega_m' : float , 'omega_lam' : float }
    _single_params = []
    _takes_rng = False
    _takes_logger = False
    halo_pos = None

    def __init__(self, mass, conc, redshift, halo_pos, 
                 omega_m=None, omega_lam=None, cosmo=None):
        self.M = float(mass)
        self.c = float(conc)
        self.z = float(redshift)
        self.halo_pos = halo_positions(halo_pos)
        self.cosmo = cosmo

        print(str(self.halo_pos.x),str(self.halo_pos.y))

class halo_positions(object):
    x = None
    y = None
    def __init__(self,positions):
        self.x = positions[0]
        self.y = positions[1]

if __name__ == '__main__':
    nfw = NFW(mass=1.23,conc=2.34,redshift=3.45,halo_pos=[4.56,5.67],omega_m=1.111,omega_lam=1.222)

so your delclaration self.halo_pos.x and self.halo_pos.y are cleaned up once init finishes.

Upvotes: 1

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