Done with activation softmax backwards

include/math/argmax.hpp

@@ -0,0 +1,176 @@
+/**++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+ * 
+ *
+ *                                              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:         argmax.hpp
+ * Revision:          0.1.0
+ * Date:              31-07-2026
+ * Author:            Michelle Bausager
+ *
+ * Description:
+ * Functions to find the index of the maximum value;
+ *
+ *++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/
+#pragma once
+
+#include <config/types.hpp>
+#include <tensor/vector.hpp> // for panic::vector
+#include <tensor/matrix.hpp> // for panic::matrix
+
+namespace panic{
+namespace math{
+
+
+
+
+/**
+ * @brief Returns the index of maximum value of a vector
+ *
+ * Computes:
+ * @code
+ * @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::types::uint_t argmax(const panic::tensor::vector<T>& a);
+
+
+/**
+ * @brief Calculates the index of the maximum value of a matrix.
+ *
+ * Computes:
+ * @code
+ * @endcode
+ *
+ * @tparam T Numeric element type.
+ * @param A Input matrix.
+ * @param b Output vector for index
+ *
+ * @return A new matrix containing the result.
+ * @return An empty matrix if the operation fails.
+ *
+ */
+template <typename T>
+bool argmax(const panic::tensor::matrix<T>& A, panic::tensor::uint_vector& b);
+
+
+/**
+ * @brief Returns the index of the maximum value of a matrix.
+ *
+ * Computes:
+ * @code
+ * @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.
+ *
+ */
+template <typename T>
+panic::types::uint_t argmax(const panic::tensor::matrix<T>& A);
+
+
+
+/**
+ * @brief Find the index of the maximum values row-wise of a matrix.
+ *
+ * Computes:
+ * @code
+ * @endcode
+ *
+ * @tparam T Numeric element type.
+ * @param A Input matrix.
+ * @param C Output vector with indexes. Resized to match @p A.cols().
+ *
+ * @return true if @p c was resized and filled successfully.
+ * @return false if vector sizes do not match or resizing @p c failed.
+ */
+template <typename T>
+bool argmax_rowwise(const panic::tensor::matrix<T>& A, panic::tensor::uint_vector& c);
+
+/**
+ * @brief Returns a new matrix containing the index of the maiximum row-wise elementwise.
+ *
+ * Computes:
+ * @code
+ * @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::uint_vector argmax_rowwise(const panic::tensor::matrix<T>& A);
+
+
+/**
+ * @brief Find the index of the maximum values column-wise of a matrix.
+ *
+ * Computes:
+ * @code
+ * @endcode
+ *
+ * @tparam T Numeric element type.
+ * @param A Input matrix.
+ * @param C Output matrix. Resized to match @p A.rows().
+ *
+ * @return true if @p c was resized and filled successfully.
+ * @return false if vector sizes do not match or resizing @p c failed.
+ */
+template <typename T>
+bool argmax_colwise(const panic::tensor::matrix<T>& A, panic::tensor::uint_vector& c);
+
+/**
+ * @brief Returns a new matrix containing the index of the maiximum column-wise elementwise.
+ *
+ * Computes:
+ * @code
+ * @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::uint_vector argmax_colwise(const panic::tensor::matrix<T>& A);
+
+} // namespace math
+} // namespace panic