| # 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. |
| |
| import numpy as np |
| |
| from _datasketches import _density_sketch, KernelFunction |
| from .KernelFunction import GaussianKernel |
| |
| class density_sketch: |
| """An instance of a Density Sketch for kernel density estimation. Requires a KernelFunction object.""" |
| |
| def __init__(self, k:int, dim:int, kernel:KernelFunction=GaussianKernel()): |
| self._kernel = kernel |
| self._gadget = _density_sketch(k, dim, self._kernel) |
| |
| @classmethod |
| def deserialize(cls, data:bytes, kernel:KernelFunction=GaussianKernel()): |
| """Reads a bytes object and returns a density sketch, using the provided kerenl or defaulting to a Guassian kerenl""" |
| self = cls.__new__(cls) |
| self._kernel = kernel |
| self._gadget = _density_sketch.deserialize(data, kernel) |
| return self |
| |
| def update(self, point:np.array): |
| """Updates the sketch with the given point""" |
| self._gadget.update(point) |
| |
| def merge(self, other:'density_sketch'): |
| """Merges the provided sketch into this one""" |
| self._gadget.merge(other._gadget) |
| |
| def is_empty(self): |
| """Returns True if the sketch is empty, otherwise False""" |
| return self._gadget.is_empty() |
| |
| def get_k(self): |
| """Returns the configured parameter k""" |
| return self._gadget.get_k() |
| |
| def get_dim(self): |
| """Returns the configured parameter dim""" |
| return self._gadget.get_dim() |
| |
| def get_n(self): |
| """Returns the length of the input stream""" |
| return self._gadget.get_n() |
| |
| def get_num_retained(self): |
| """Returns the number of retained items (samples) in the sketch""" |
| return self._gadget.get_num_retained() |
| |
| def is_estimation_mode(self): |
| """Returns True if the sketch is in estimation mode, otherwise False""" |
| return self._gadget.is_estimation_mode() |
| |
| def get_estimate(self, point:np.array): |
| """Returns an approximate density at the given point""" |
| return self._gadget.get_estimate(point) |
| |
| def serialize(self): |
| """Serializes the sketch into a bytes object""" |
| return self._gadget.serialize() |
| |
| def __str__(self, print_levels:bool=False, print_items:bool=False): |
| """Produces a string summary of the sketch""" |
| return self._gadget.to_string(print_levels, print_items) |
| |
| def to_string(self, print_levels:bool=False, print_items:bool=False): |
| """Produces a string summary of the sketch""" |
| return self._gadget.to_string(print_levels, print_items) |
| |
| def __iter__(self): |
| return self._gadget.__iter__() |