django1/django/contrib/postgres/aggregates/statistics.py

81 lines
2.0 KiB
Python

from django.db.models import FloatField, IntegerField
from django.db.models.aggregates import Aggregate
__all__ = [
'CovarPop', 'Corr', 'RegrAvgX', 'RegrAvgY', 'RegrCount', 'RegrIntercept',
'RegrR2', 'RegrSlope', 'RegrSXX', 'RegrSXY', 'RegrSYY', 'StatAggregate',
]
class StatAggregate(Aggregate):
def __init__(self, y, x, output_field=FloatField()):
if not x or not y:
raise ValueError('Both y and x must be provided.')
super(StatAggregate, self).__init__(y=y, x=x, output_field=output_field)
self.x = x
self.y = y
self.source_expressions = self._parse_expressions(self.y, self.x)
def get_source_expressions(self):
return self.y, self.x
def set_source_expressions(self, exprs):
self.y, self.x = exprs
def resolve_expression(self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False):
return super(Aggregate, self).resolve_expression(query, allow_joins, reuse, summarize)
class Corr(StatAggregate):
function = 'CORR'
class CovarPop(StatAggregate):
def __init__(self, y, x, sample=False):
self.function = 'COVAR_SAMP' if sample else 'COVAR_POP'
super(CovarPop, self).__init__(y, x)
class RegrAvgX(StatAggregate):
function = 'REGR_AVGX'
class RegrAvgY(StatAggregate):
function = 'REGR_AVGY'
class RegrCount(StatAggregate):
function = 'REGR_COUNT'
def __init__(self, y, x):
super(RegrCount, self).__init__(y=y, x=x, output_field=IntegerField())
def convert_value(self, value, expression, connection, context):
if value is None:
return 0
return int(value)
class RegrIntercept(StatAggregate):
function = 'REGR_INTERCEPT'
class RegrR2(StatAggregate):
function = 'REGR_R2'
class RegrSlope(StatAggregate):
function = 'REGR_SLOPE'
class RegrSXX(StatAggregate):
function = 'REGR_SXX'
class RegrSXY(StatAggregate):
function = 'REGR_SXY'
class RegrSYY(StatAggregate):
function = 'REGR_SYY'