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

70 lines
1.7 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):
output_field = FloatField()
def __init__(self, y, x, output_field=None, filter=None):
if not x or not y:
raise ValueError('Both y and x must be provided.')
super().__init__(y, x, output_field=output_field, filter=filter)
def resolve_expression(self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False):
return super().resolve_expression(query, allow_joins, reuse, summarize)
class Corr(StatAggregate):
function = 'CORR'
class CovarPop(StatAggregate):
def __init__(self, y, x, sample=False, filter=None):
self.function = 'COVAR_SAMP' if sample else 'COVAR_POP'
super().__init__(y, x, filter=filter)
class RegrAvgX(StatAggregate):
function = 'REGR_AVGX'
class RegrAvgY(StatAggregate):
function = 'REGR_AVGY'
class RegrCount(StatAggregate):
function = 'REGR_COUNT'
output_field = IntegerField()
def convert_value(self, value, expression, connection):
return 0 if value is None else 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'