71 lines
2.2 KiB

"""Karma logging models."""
import math
import random
import pytz
from django.conf import settings
from django.db import models
class PiLogManager(models.Manager):
"""Assemble some queries against PiLog."""
def simulate(self):
"""Add one more entry to the log, and return it."""
latest = self.latest()
except PiLog.DoesNotExist:
latest = PiLog.objects.create(simulation_x=0.0, simulation_y=0.0,
total_count_inside=0, total_count=0)
inside = latest.total_count_inside
total = latest.total_count
x = random.random()
y = random.random()
total += 1
if math.hypot(x, y) < 1:
inside += 1
newest = PiLog.objects.create(simulation_x=x, simulation_y=y,
total_count_inside=inside, total_count=total)
# TODO: remove the x, y return values, now that we track them in the object
return newest, x, y
class PiLog(models.Model):
"""Track pi as it is estimated over time."""
simulation_x = models.DecimalField(max_digits=11, decimal_places=10)
simulation_y = models.DecimalField(max_digits=11, decimal_places=10)
total_count_inside = models.PositiveIntegerField()
total_count = models.PositiveIntegerField()
created = models.DateTimeField(auto_now_add=True)
objects = PiLogManager()
class Meta:
"""Options for the PiLog class."""
get_latest_by = 'created'
def __str__(self):
"""Provide string representation."""
tz = pytz.timezone(settings.TIME_ZONE)
return "({0:d}/{1:d}) @ {2:s}".format(self.total_count_inside, self.total_count,
self.created.astimezone(tz).strftime('%Y-%m-%d %H:%M:%S %Z'))
def value(self):
"""Return this log entry's estimated value of pi."""
if self.total_count == 0:
return 0.0
return 4.0 * int(self.total_count_inside) / int(self.total_count)
def hit(self):
"""Return if this log entry is inside the unit circle."""
return math.hypot(self.simulation_x, self.simulation_y) < 1