LocalUtil.py 文件源码

def calcELBOSingleDoc_Fast(wc_d, DocTopicCount_d, Prior_d, sumR_d, alphaEbeta):
  ''' Evaluate ELBO contributions for single doc, dropping terms constant wrt local step.

      Note: key to some progress was remembering that Prior_d is not just exp(ElogPi)
            but that it is usually altered by a multiplicative constant for safety
            we can find this constant offset (in logspace), and adjust sumR_d accordingly
  '''
  theta_d = DocTopicCount_d + alphaEbeta[:-1]
  thetaRem = alphaEbeta[-1]

  digammaSum = digamma(theta_d.sum() + thetaRem)
  ElogPi_d = digamma(theta_d) - digammaSum
  ElogPiRem = digamma(thetaRem) - digammaSum                  

  cDir = -1 * c_Dir(theta_d[np.newaxis,:], thetaRem)
  slackOn = np.inner(DocTopicCount_d + alphaEbeta[:-1] - theta_d,
                     ElogPi_d.flatten())
  slackOff = (alphaEbeta[-1] - thetaRem) * ElogPiRem
  rest = np.inner(wc_d, np.log(sumR_d)) - np.inner(DocTopicCount_d, np.log(Prior_d+1e-100))

  return cDir + slackOn + slackOff + rest