ó
áp7]c           @  s±  d  Z  d d l m Z d d l Z d d l m Z m Z m 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 d l m Z d „  Z d „  Z d „  Z d „  Z d „  Z d „  Z d d d d „ Z e j d d „ Z e  d k r­e j! d d d g d d d g d d d g g ƒ Z" e j! d d d g d d d g d d d g g ƒ Z# e j! d d d g d d d g d d d g g ƒ Z$ e$ Z% e j& e j e j d g ƒ Z' e j& d d d g ƒ Z' e j& d d d g ƒ Z( e j& d d d g ƒ Z( d e' (d e( (d Z) e j* e) ƒ Z+ e, e e' e( e" d d  ƒƒ e, e j- j. e( d e) ƒ e j- j. e' d e) ƒ d ƒ d Z/ e, e e/ e' e+ e/ e( e+ e% ƒ ƒ d! Z) e, e e' e( e% e) ƒ ƒ e j& d d g d d g g ƒ Z0 e, e d d" g e0 d# d$ ƒ ƒ d% Z1 e d d" g e0 d# e1 ƒ Z2 e, e j3 e2 d d" g k  j4 d ƒ d ƒ d e1 ƒ e, e e j e j5 d# ƒ e j6 d# ƒ e% d d# … d d# … f d# ƒ ƒ n  d S(&   s2  Multivariate Distribution

Probability of a multivariate t distribution

Now also mvstnormcdf has tests against R mvtnorm

Still need non-central t, extra options, and convenience function for
location, scale version.

Author: Josef Perktold
License: BSD (3-clause)

Reference:
Genz and Bretz for formula

iÿÿÿÿ(   t   print_functionN(   t	   integratet   statst   special(   t   chii   (   t   mvstdnormcdf(   t   exp(   t   log(   t   gamma(   t   gammalnc         C  sK   | | d d t  j | d ƒ } | t j | d ƒ d | d :} | S(   s   pdf of chi-square distributiong       @i   i   (   t   npR   R   R   (   t   selft   xt   dft   Px(    (    sM   lib/python2.7/site-packages/statsmodels/sandbox/distributions/multivariate.pyt   chi2_pdf   s    $#c         C  sO   | d t  |  ƒ |  |  d | d d t  d ƒ t | d ƒ } t | ƒ S(   Ng      ð?g      à?i   g       @(   t   np_logt   sps_gammalnt   np_exp(   R   R   t   tmp(    (    sM   lib/python2.7/site-packages/statsmodels/sandbox/distributions/multivariate.pyt   chi_pdf$   s    Ec         C  sI   | d t  |  ƒ |  |  d | d d t  d ƒ t | d ƒ } | S(   Ng      ð?g      à?i   g       @(   R   R   (   R   R   R   (    (    sM   lib/python2.7/site-packages/statsmodels/sandbox/distributions/multivariate.pyt
   chi_logpdf*   s    Ec      
   C  sj   t  j | d ƒ } t |  | ƒ } | t t |  | | |  | | | d d d d ƒƒ 7} t | ƒ } | S(   Ng      à?t   maxptsi@B t   absepsgíµ ÷Æ°>(   R
   t   sqrtR   R   R   R   (   t   st   at   bt   RR   t   sqrt_dft   ret(    (    sM   lib/python2.7/site-packages/statsmodels/sandbox/distributions/multivariate.pyt   funbgh/   s    %c      	   C  s{   t  | ƒ } t j | ƒ } t | d t |  ƒ |  |  d ƒ t |  | | |  | | | t j | d ƒ d d d d ƒS(   Ni   g      à?iÿÿÿÿR   i@B R   g-Cëâ6?(   t   lenR
   R   R   R   R   t   tril_indices(   R   R   R   R   R   t   nR   (    (    sM   lib/python2.7/site-packages/statsmodels/sandbox/distributions/multivariate.pyt   funbgh27   s
    #/c         C  s&   t  j d d |  d ƒ t |  d ƒ S(   Ng       @i   g      à?(   R
   t   powert	   sps_gamma(   R   (    (    sM   lib/python2.7/site-packages/statsmodels/sandbox/distributions/multivariate.pyt	   bghfactor?   s    gñhãˆµøä>c      	   C  s   t  d |  | | | f d d d d d d ƒ } | d	 k	 rI | j | ƒ n  t j | d | g | ƒ \ } }	 t j t | |	 |  \ }
 } |
 t | ƒ } | S(
   s8  
    Probability of rectangular area of standard t distribution

    assumes mean is zero and R is correlation matrix

    Notes
    -----
    This function does not calculate the estimate of the combined error
    between the underlying multivariate normal probability calculations
    and the integration.
    t   argst   epsabsg-Cëâ6?t   epsrelg{®Gáz„?t   limiti–   i   N(	   t   dictt   Nonet   updateR   t   ppfR   t   quadR#   R&   (   R   R   R   R   t   iepst   quadkwdst   mvstkwdst   kwdst   lowert   uppert   rest   errt   prob(    (    sM   lib/python2.7/site-packages/statsmodels/sandbox/distributions/multivariate.pyt
   mvstdtprobC   s    -"c         C  s•   t  j |  ƒ }  t |  ƒ } | t  j k r3 d } n t  j j | | ƒ | } t  j j t  j | ƒ | | f ƒ } |  | t  j | ƒ d d … d f S(   s  generate random variables of multivariate t distribution

    Parameters
    ----------
    m : array_like
        mean of random variable, length determines dimension of random variable
    S : array_like
        square array of covariance  matrix
    df : int or float
        degrees of freedom
    n : int
        number of observations, return random array will be (n, len(m))

    Returns
    -------
    rvs : ndarray, (n, len(m))
        each row is an independent draw of a multivariate t distributed
        random variable


    g      ð?N(
   R
   t   asarrayR    t   inft   randomt	   chisquaret   multivariate_normalt   zerosR   R,   (   t   mt   SR   R"   t   dR   t   z(    (    sM   lib/python2.7/site-packages/statsmodels/sandbox/distributions/multivariate.pyt   multivariate_t_rvsY   s    	$t   __main__g      ð?i    g      à?g      YÀg¸…ëQ¸î¿g        g¸…ëQ¸î?i   g      $@R   gíµ ÷Æ°>i   g      4@i   i   i'  (7   t   __doc__t
   __future__R    t   numpyR
   t   scipyR   R   R   t   scipy.statsR   t   extrasR   R   R   R   R   t   scipy.specialR   R%   R	   R   R   R   R   R   R#   R&   R,   R9   R;   RD   t   __name__R:   t   corrt
   corr_indept
   corr_equalR   t   arrayR   R   R   R   R   t   printt   tt   cdfR   RA   t   nobst   rvstt   sumt   allt   onesR?   (    (    (    sM   lib/python2.7/site-packages/statsmodels/sandbox/distributions/multivariate.pyt   <module>   sV   						"333 8&!3I