U
    9%e                     @   sR   d dl mZ d dlZd dlmZ d dlmZ d dlmZ dgZ	G dd deZ
dS )    )NumberN)constraints)ExponentialFamily)broadcast_allPoissonc                       s   e Zd ZdZdejiZejZe	dd Z
e	dd Ze	dd Zd fd
d	Zd fdd	Ze fddZdd Ze	dd Zdd Z  ZS )r   a  
    Creates a Poisson distribution parameterized by :attr:`rate`, the rate parameter.

    Samples are nonnegative integers, with a pmf given by

    .. math::
      \mathrm{rate}^k \frac{e^{-\mathrm{rate}}}{k!}

    Example::

        >>> # xdoctest: +SKIP("poisson_cpu not implemented for 'Long'")
        >>> m = Poisson(torch.tensor([4]))
        >>> m.sample()
        tensor([ 3.])

    Args:
        rate (Number, Tensor): the rate parameter
    ratec                 C   s   | j S Nr   self r   Z/var/www/html/Darija-Ai-API/env/lib/python3.8/site-packages/torch/distributions/poisson.pymean!   s    zPoisson.meanc                 C   s
   | j  S r   )r   floorr
   r   r   r   mode%   s    zPoisson.modec                 C   s   | j S r   r	   r
   r   r   r   variance)   s    zPoisson.varianceNc                    s>   t |\| _t|tr t }n
| j }t j||d d S )Nvalidate_args)	r   r   
isinstancer   torchSizesizesuper__init__)r   r   r   batch_shape	__class__r   r   r   -   s
    


zPoisson.__init__c                    sD   |  t|}t|}| j||_tt|j|dd | j|_|S )NFr   )	Z_get_checked_instancer   r   r   r   expandr   r   _validate_args)r   r   Z	_instancenewr   r   r   r   5   s    
zPoisson.expandc              
   C   s<   |  |}t   t| j|W  5 Q R  S Q R X d S r   )Z_extended_shaper   Zno_gradZpoissonr   r   )r   Zsample_shapeshaper   r   r   sample=   s    

zPoisson.samplec                 C   s:   | j r| | t| j|\}}||| |d   S )N   )r   Z_validate_sampler   r   Zxlogylgamma)r   valuer   r   r   r   log_probB   s    
zPoisson.log_probc                 C   s   t | jfS r   )r   logr   r
   r   r   r   _natural_paramsH   s    zPoisson._natural_paramsc                 C   s
   t |S r   )r   exp)r   xr   r   r   _log_normalizerL   s    zPoisson._log_normalizer)N)N)__name__
__module____qualname____doc__r   ZnonnegativeZarg_constraintsZnonnegative_integerZsupportpropertyr   r   r   r   r   r   r   r!   r%   r'   r*   __classcell__r   r   r   r   r      s    




)numbersr   r   Ztorch.distributionsr   Ztorch.distributions.exp_familyr   Ztorch.distributions.utilsr   __all__r   r   r   r   r   <module>   s   