U
    9%eo                     @   sf   d dl Z d dlZd dlmZ d dlm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 )	    N)inf)constraints)Normal)TransformedDistribution)AbsTransform
HalfNormalc                       s   e Zd ZdZdejiZejZdZ	d fdd	Z
d fdd	Zed	d
 Zedd Zedd Zedd Zdd Zdd Zdd Zdd Z  ZS )r   a  
    Creates a half-normal distribution parameterized by `scale` where::

        X ~ Normal(0, scale)
        Y = |X| ~ HalfNormal(scale)

    Example::

        >>> # xdoctest: +IGNORE_WANT("non-deterinistic")
        >>> m = HalfNormal(torch.tensor([1.0]))
        >>> m.sample()  # half-normal distributed with scale=1
        tensor([ 0.1046])

    Args:
        scale (float or Tensor): scale of the full Normal distribution
    scaleTNc                    s&   t d|dd}t j|t |d d S )Nr   F)validate_args)r   super__init__r   )selfr   r	   	base_dist	__class__ ^/var/www/html/Darija-Ai-API/env/lib/python3.8/site-packages/torch/distributions/half_normal.pyr   "   s    zHalfNormal.__init__c                    s   |  t|}t j||dS )N)	_instance)Z_get_checked_instancer   r
   expand)r   Zbatch_shaper   newr   r   r   r   &   s    zHalfNormal.expandc                 C   s   | j jS N)r   r   r   r   r   r   r   *   s    zHalfNormal.scalec                 C   s   | j tdtj  S N   )r   mathsqrtpir   r   r   r   mean.   s    zHalfNormal.meanc                 C   s   t | jS r   )torchZ
zeros_liker   r   r   r   r   mode2   s    zHalfNormal.modec                 C   s   | j dddtj   S Nr      )r   powr   r   r   r   r   r   variance6   s    zHalfNormal.variancec                 C   s>   | j r| | | j|td }t|dk|t }|S )Nr   r   )	_validate_args_validate_sampler   log_probr   logr   wherer   )r   valuer%   r   r   r   r%   :   s
    
zHalfNormal.log_probc                 C   s$   | j r| | d| j| d S r   )r#   r$   r   cdf)r   r(   r   r   r   r)   A   s    
zHalfNormal.cdfc                 C   s   | j |d d S )Nr    r   )r   icdf)r   Zprobr   r   r   r*   F   s    zHalfNormal.icdfc                 C   s   | j  td S r   )r   entropyr   r&   r   r   r   r   r+   I   s    zHalfNormal.entropy)N)N)__name__
__module____qualname____doc__r   ZpositiveZarg_constraintsZnonnegativeZsupportZhas_rsampler   r   propertyr   r   r   r"   r%   r)   r*   r+   __classcell__r   r   r   r   r      s$   




)r   r   r   Ztorch.distributionsr   Ztorch.distributions.normalr   Z,torch.distributions.transformed_distributionr   Ztorch.distributions.transformsr   __all__r   r   r   r   r   <module>   s   