GetPhiPrime: Calculate a matrix whose rows represent P(topic_i|tokens)

In ChengMengli/topic: Functions for Text Mining and Topic Modeling

Description

This function takes a phi matrix (P(token|topic)) and a theta matrix (P(topic|document)) and returns the phi prime matrix (P(topic|token)). Phi prime can be used for classifying new documents and for alternative topic labels. This function is deprecated. Use CalcPhiPrime instead.

Usage

GetPhiPrime(phi, theta)

Arguments

phi	= The phi matrix whose rows index topics and columns index words. The i, j entries are P(word_i | topic_j)
theta	= The theta matrix whose rows index documents and columns index topics. The i, j entries are P(topic_i | document_j)

Value

Returns a matrix whose rows correspond to topics and whose columns correspond to tokens. The i,j entry corresponds to P(topic_i|token_j)

Examples

# Load a pre-formatted dtm and topic model
data(nih_sample_topic_model) 

# Make a phi_prime matrix, P(topic|words)
phi_prime <- GetPhiPrime(phi = nih_sample_topic_model$phi, 
                         theta = nih_sample_topic_model$theta)

ChengMengli/topic documentation built on May 31, 2019, 8:44 p.m.