/* ----------------------------------------------------------------------- *//**
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 *
 * @file avg_var.sql_in
 *
 * @brief SQL functions for average and variance
 * @date September 2015
 *
 *
 *//* ----------------------------------------------------------------------- */

m4_include(`SQLCommon.m4')

---------------------------------------------------------------------------
-- Functions for user-defined aggregates
---------------------------------------------------------------------------
-- normal
CREATE OR REPLACE FUNCTION MADLIB_SCHEMA.avg_var_merge_states(
    state1 double precision[],
    state2 double precision[])
RETURNS double precision[] AS 'MODULE_PATHNAME', 'avg_var_merge_states'
LANGUAGE C
IMMUTABLE STRICT
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `NO SQL', `');

CREATE OR REPLACE FUNCTION MADLIB_SCHEMA.avg_var_final(
    state double precision[])
RETURNS double precision[] AS 'MODULE_PATHNAME'
LANGUAGE C 
IMMUTABLE STRICT
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `NO SQL', `');

CREATE OR REPLACE FUNCTION MADLIB_SCHEMA.avg_var_transition(
    state double precision[],
    x double precision)
RETURNS double precision[] AS 'MODULE_PATHNAME'
LANGUAGE C
IMMUTABLE STRICT
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `NO SQL', `');
---------------------------------------------------------------------------

---------------------------------------------------------------------------
-- User-defined aggregates
---------------------------------------------------------------------------
DROP AGGREGATE IF EXISTS MADLIB_SCHEMA.avg_var(DOUBLE PRECISION);
CREATE AGGREGATE MADLIB_SCHEMA.avg_var(
		DOUBLE PRECISION) (

    SFUNC=MADLIB_SCHEMA.avg_var_transition,
    STYPE=double precision[],
    FINALFUNC=MADLIB_SCHEMA.avg_var_final,
    m4_ifdef(`__POSTGRESQL__', `', `prefunc=MADLIB_SCHEMA.avg_var_merge_states,')
    INITCOND='{0, 0, 0}'
);