# coding=utf-8

"""
@file lmf_igd.py_in

@brief Low-rank Matrix Factorization using IGD: Driver functions

@namespace lmf_igd

@brief Low-rank Matrix Factorization using IGD: Driver functions
"""

from utilities.control import IterationController2S
from utilities.control import OptimizerControl

def compute_lmf_igd(schema_madlib, rel_args, rel_state, rel_source,
    col_row, col_column, col_value, **kwargs):
    """
    Driver function for Low-rank Matrix Factorization using IGD

    @param schema_madlib Name of the MADlib schema, properly escaped/quoted
    @rel_args Name of the (temporary) table containing all non-template
        arguments
    @rel_state Name of the (temporary) table containing the inter-iteration
        states
    @param rel_source Name of the relation containing input points
    @param col_row Name of the row column
    @param col_column Name of the column (in the matrix sense) column
    @param col_value Name of the value column
    @param kwargs We allow the caller to specify additional arguments (all of
        which will be ignored though). The purpose of this is to allow the
        caller to unpack a dictionary whose element set is a superset of
        the required arguments by this function.
    @return The iteration number (i.e., the key) with which to look up the
        result in \c rel_state
    """

    # We disable ORCA since this function creates an edge case where
    # the performance is worse than the planner. (MADLIB-1170)

    with OptimizerControl(False):
        iterationCtrl = IterationController2S(
            rel_args = rel_args,
            rel_state = rel_state,
            stateType = "DOUBLE PRECISION[]",
            truncAfterIteration = False,
            schema_madlib = schema_madlib, # Identifiers start here
            rel_source = rel_source,
            col_row = col_row,
            col_column = col_column,
            col_value = col_value)
        with iterationCtrl as it:
            it.iteration = 0
            while True:
                it.update("""
                    SELECT
                        {schema_madlib}.lmf_igd_step(
                            (_src.{col_row})::integer,
                            (_src.{col_column})::integer,
                            (_src.{col_value})::integer,
                            (SELECT _state FROM {rel_state}
                                WHERE _iteration = {iteration}),
                            (_args.row_dim)::integer,
                            (_args.column_dim)::integer,
                            (_args.max_rank)::integer,
                            (_args.stepsize)::FLOAT8,
                            (_args.scale_factor)::FLOAT8)
                    FROM {rel_source} AS _src, {rel_args} AS _args
                    """)
                if it.test("""
                    {iteration} > _args.num_iterations OR
                    {schema_madlib}.internal_lmf_igd_distance(
                        _state_previous, _state_current) < _args.tolerance
                    """):
                    break
        return iterationCtrl.iteration