U
    ©Ê¹jZ	  ã                   @   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ƒZdS )	é    N)Úinf)Úconstraints)ÚCauchy)ÚTransformedDistribution)ÚAbsTransformÚ
HalfCauchyc                       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
„ ƒZedd„ ƒZedd„ ƒZedd„ ƒZdd„ Zdd„ Zdd„ Zdd„ Z‡  ZS )r   a³  
    Creates a half-Cauchy distribution parameterized by `scale` where::

        X ~ Cauchy(0, scale)
        Y = |X| ~ HalfCauchy(scale)

    Example::

        >>> # xdoctest: +IGNORE_WANT("non-deterinistic")
        >>> m = HalfCauchy(torch.tensor([1.0]))
        >>> m.sample()  # half-cauchy distributed with scale=1
        tensor([ 2.3214])

    Args:
        scale (float or Tensor): scale of the full Cauchy distribution
    ÚscaleTNc                    s&   t d|dd�}tƒ j|tƒ |d� d S )Nr   F)Úvalidate_args)r   ÚsuperÚ__init__r   )Úselfr   r	   Ú	base_dist©Ú	__class__© ú^/var/www/html/bwave/python/venv/lib/python3.8/site-packages/torch/distributions/half_cauchy.pyr   "   s    zHalfCauchy.__init__c                    s   |   t|¡}tƒ j||d�S )N)Ú	_instance)Z_get_checked_instancer   r
   Úexpand)r   Zbatch_shaper   Únewr   r   r   r   &   s    zHalfCauchy.expandc                 C   s   | j jS ©N)r   r   ©r   r   r   r   r   *   s    zHalfCauchy.scalec                 C   s    t j|  ¡ tj| jj| jjd�S )N©ÚdtypeÚdevice)ÚtorchÚfullZ_extended_shapeÚmathr   r   r   r   r   r   r   r   Úmean.   s    üzHalfCauchy.meanc                 C   s   t  | j¡S r   )r   Z
zeros_liker   r   r   r   r   Úmode7   s    zHalfCauchy.modec                 C   s   | j jS r   )r   Úvariancer   r   r   r   r   ;   s    zHalfCauchy.variancec                 C   sZ   | j r|  |¡ tj|| jjj| jjjd�}| j |¡t	 
d¡ }t |dk|t ¡}|S )Nr   é   r   )Ú_validate_argsÚ_validate_sampler   Z	as_tensorr   r   r   r   Úlog_probr   ÚlogÚwherer   )r   Úvaluer#   r   r   r   r#   ?   s    
  ÿzHalfCauchy.log_probc                 C   s$   | j r|  |¡ d| j |¡ d S )Nr    é   )r!   r"   r   Úcdf)r   r&   r   r   r   r(   I   s    
zHalfCauchy.cdfc                 C   s   | j  |d d ¡S )Nr'   r    )r   Úicdf)r   Zprobr   r   r   r)   N   s    zHalfCauchy.icdfc                 C   s   | j  ¡ t d¡ S )Nr    )r   Úentropyr   r$   r   r   r   r   r*   Q   s    zHalfCauchy.entropy)N)N)Ú__name__Ú
__module__Ú__qualname__Ú__doc__r   ZpositiveZarg_constraintsZnonnegativeZsupportZhas_rsampler   r   Úpropertyr   r   r   r   r#   r(   r)   r*   Ú__classcell__r   r   r   r   r      s$   





)r   r   r   Ztorch.distributionsr   Ztorch.distributions.cauchyr   Z,torch.distributions.transformed_distributionr   Ztorch.distributions.transformsr   Ú__all__r   r   r   r   r   Ú<module>   s   