# Copyright 2019 Huawei Technologies Co., Ltd
#
# Licensed 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 akg.tvm
import akg.topi
import akg
import numpy as np


class bernoulli:
    """
    Bernoulli distribution

    Args:
        log_prob (x):
            logarithm of probability density function
    """
    def __init__(self, probs, dtype="float16"):
        self.probs = probs
        self.dtype = dtype

    def log_prob(self, x):
        one = akg.tvm.const(1.0, self.dtype)
        result = akg.topi.log(one - self.probs) * (one - x) + akg.topi.log(self.probs) * x
        return result
