/**++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 *
 *                                              PANIC
 *                              Portable Algorithms and Numerics In C++
 *
 *                       Scientific computing from scratch, with feeling.
 *
 * Copyright (c) 2026 Michelle Bausager
 *
 * This file is part of PANIC.
 *
 * PANIC is free software licensed under the GNU General Public License v3.0 or later.
 * You may redistribute and/or modify it under the terms of the GPL.
 *
 * PANIC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the LICENSE file for the full license text.
 *
 * SPDX-License-Identifier: GPL-3.0-or-later
 *
 *++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 *
 * Project Name:      PANIC
 * Module Name:       math
 * File Name:         log.cpp
 * Revision:          0.1.0
 * Date:              29-07-2026
 * Author:            Michelle Bausager
 *
 * Description:
 * Functions to calculate the logorithem of numbers
 *
 *++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/
#pragma once

#include <tensor/vector.hpp> // for panic::vector
#include <tensor/matrix.hpp> // for panic::matrix

namespace panic{
namespace math{



/**
 * @brief calculates the exponential of a value.
 *
 * Computes:
 * @code
 * result = exp(k)
 * @endcode
 *
 * @tparam T Numeric element type.
 * @param k Value to take the exp of.
 *
 * @return The calculated value
 *
 * @note This function is omp-friendly.
 */
template <typename T>
T exp(const T x);


/**
 * @brief Calculates the exponential elementwise in a vector
 *
 * Computes:
 * @code
 * c[i] = exp(a[i])
 * @endcode
 *
 * @tparam T Numeric element type.
 * @param a Input vector.
 * @param c Output vector. Resized to match @p a.
 *
 * @return true if @p c was resized and filled successfully.
 * @return false if resizing @p c failed.
 *
 * @note This overload writes the result into an existing vector to avoid
 *       unnecessary temporary allocations.
 */
template <typename T>
bool exp(const panic::tensor::vector<T>& a, panic::tensor::vector<T>& c);

/**
 * @brief Calculates the exponential elementwise in a vector
 *
 * Computes:
 * @code
 * result[i] = exp(a[i])
 * @endcode
 *
 * @tparam T Numeric element type.
 * @param a Input vector.
 *
 * @return A new vector containing the result.
 * @return An empty vector if the operation fails.
 *
 * @note This overload is convenient, but may allocate a new vector.
 */
template <typename T>
panic::tensor::vector<T> add(const panic::tensor::vector<T>& a);

/**
 * @brief Calculates the expnential elementwise of a matrix
 *
 * Computes:
 * @code
 * C(i,j) = exp(A(i,j))
 * @endcode
 *
 * @tparam T Numeric element type.
 * @param A Input matrix.
 * @param C Output Matrix. Resized to match @p A.
 *
 * @return true if @p C was resized and filled successfully.
 * @return false if resizing @p C failed.
 *
 * @note This overload writes the result into an existing vector to avoid
 *       unnecessary temporary allocations.
 */
template <typename T>
bool exp(const panic::tensor::matrix<T>& A, panic::tensor::matrix<T>& C);

/**
 * @brief Returns the calculated ecponential elementwise of the matrix
 *
 * Computes:
 * @code
 * result(i,j) = exp(A(i,j))
 * @endcode
 *
 * @tparam T Numeric element type.
 * @param A Input matrix.
 *
 * @return A new matrix containing the result.
 * @return An empty matrix if the operation fails.
 *
 * @note This overload is convenient, but may allocate a new vector.
 */
template <typename T>
panic::tensor::matrix<T> exp(const panic::tensor::matrix<T>& A);

} // namespace math
} // namespace panic