# -*- coding: utf-8 -*-
# Copyright 2022 The PsiZ Datasets Authors. All Rights Reserved.
#
# 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.
# ============================================================================
"""Module of utility functions.

Functions:
    one_hot: Encode sparse index to one-hot representation.

"""

import numpy as np


def one_hot(index, n_outcome):
    """Encode sparse index to one-hot representation.

    Args:
        index: A sparse index.
        n_outcome: An integer indicating the number of outcomes.

    Returns:
        A np.NDArray one-hot representation.

    """
    x = np.zeros(n_outcome, dtype=np.float32)
    x[index] = 1.0
    return x
