probcomp/bayeslite

latent variables cannot be inputs to CGPM foreign models

Open

#445 opened on Jul 12, 2016

View on GitHub
 (0 comments) (0 reactions) (0 assignees)Python (915 stars) (63 forks)batch import
help wantedk min/hr

Description

create generator g for p using cgpm (
    model foo given err using venturescript (sp = errfoo),
    latent err numerical
)

This will not work because cgpm_metamodel._create_schema assumes that every input to a foreign model exists as a manifest variable of the population, and passes them to core.bayesdb_variable_stattype to determine the statistical type.

The logic in _create_schema must be changed to defer whatever processing requires the statistical types of inputs to foreign models until after all clauses have been ingested, and then update that processing to use latents (the mapping from latent variable names to their respective statistical types) instead of core.bayesdb_variable_stattype when appropriate.

Contributor guide

Tech stack
python
Domain
backenddata
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Pythonbayeslite internalsCGPM conceptbasic Bayesian statistics
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
10
Research direction
The issue is in `cgpm metamodel. create schema` in the bayeslite codebase. It currently assumes all inputs to foreign models are manifest variables, but latent variables should also be allowed. The fix requires deferring the statistical type determination for foreign model inputs until after all clauses are processed, then using the `latents` mapping instead of `core.bayesdb variable stattype`. Start by examining the ` create schema` method and understanding how it processes foreign models, then design a change that separates the input validation from type resolution.