panic/src/neural_network/layer/layer.cpp

/**++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 *
 *                                              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:       neural_network
 * File Name:         layer_dense.cpp
 * Revision:          0.1.0
 * Date:              23-06-2026
 * Author:            Michelle Bausager
 *
 * Description:
 * Defines the dense layers used in neural network
 *
 *++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/

//---------------------------------------------------------------------------------------------------------------------------
// INCLUDE DESCRIPTION
//---------------------------------------------------------------------------------------------------------------------------
#include <tensor/vector.hpp>
#include <config/omp.hpp>

//---------------------------------------------------------------------------------------------------------------------------
// DEFINE DESCRIPTION
//---------------------------------------------------------------------------------------------------------------------------

//---------------------------------------------------------------------------------------------------------------------------
// TYPE DESCRIPTION
//---------------------------------------------------------------------------------------------------------------------------

//---------------------------------------------------------------------------------------------------------------------------
// VARIABLE DESCRIPTION
//---------------------------------------------------------------------------------------------------------------------------
static const panic::uint_t vector_omp_min_size = 10000;

//---------------------------------------------------------------------------------------------------------------------------
// FUNCTION PROTOTYPE
//---------------------------------------------------------------------------------------------------------------------------
namespace panic{
	namespace tensor{


//--------------------------------------------------------------------------------------------------------------------------
// Constructor Name : panic::tensor::vector::vector
//
// Description:
//		Creates an empty vector.
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
vector<T>::vector() {
	length = 0;
	data = 0;
}

//--------------------------------------------------------------------------------------------------------------------------
// Constructor Name : panic::tensor::vector::vector
//
// Description:
//		Creates a vector with size allocation and initializes all values to zero.
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
vector<T>::vector(panic::uint_t size){
	length = size;

	if (length == 0){
		data = 0;
		return;
	}

	data = new T[length];

	PANIC_OMP_PARALLEL_FOR_IF(length > vector_omp_min_size)
	for (panic::uint_t i = 0; i < size; ++i){
		data[i] = static_cast<T>(0);
	}

}

//--------------------------------------------------------------------------------------------------------------------------
// Constructor Name : panic::tensor::vector::vector
//
// Description:
//		Creates a vector with size allocation and initializes all values.
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
vector<T>::vector(panic::uint_t size, T value){
	length = size;

	if (size == 0){
		data = 0;
		return;
	}

	data = new T[size];

	PANIC_OMP_PARALLEL_FOR_IF(length > vector_omp_min_size)
	for (panic::uint_t i = 0; i < size; ++i){
		data[i] = value;
	}
}

//--------------------------------------------------------------------------------------------------------------------------
// Constructor Name : panic::tensor::vector::vector
//
// Description:
//		Copy-contructor, makes a deep copy of another vector like this:
//		vector a(3);
// 		vector b = a;
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
vector<T>::vector(const vector& other){
	length = other.length;

	if (length == 0){
		data = 0;
		return;
	}

	data = new T[length];

	PANIC_OMP_PARALLEL_FOR_IF(length > vector_omp_min_size)
	for (panic::uint_t i = 0; i < length; ++i){
		data[i] = other.data[i];
	}
}

//--------------------------------------------------------------------------------------------------------------------------
// Deconstructor Name : panic::tensor::vector::~vector
//
// Description:
//		Deletes the data and releases the memory.
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
vector<T>::~vector(){
	delete[] data;

	data = 0;
	length = 0;
}

//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::tensor::vector::operator=
//
// Description:
//		Copy-assignment. Copies from another vector like this:
//		vector a(5);
//		vector b(3);
//		b = a;
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
vector<T>& vector<T>::operator=(const vector& other){
	if (this == &other){
		return *this;
	}

	T* new_data = 0;

	if (other.length > 0){
		new_data = new T[other.length];

		PANIC_OMP_PARALLEL_FOR_IF(length > vector_omp_min_size)
		for (panic::uint_t i = 0; i < other.length; ++i){
			new_data[i] = other.data[i];
		}
	}

	delete[] data;

	data = new_data;
	length = other.length;

	return *this;
}

//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::tensor::vector::resize
//
// Description:
//		Returns the length/size of the vector
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
panic::uint_t vector<T>::size() const{
	return length;
}

//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::tensor::vector::resize
//
// Description:
//		Resizes the vector to new length and keeps old values
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
bool vector<T>::resize(panic::uint_t new_size){
	if (new_size == length){
		return true;
	}

	if (new_size == 0){
		data = 0;
		length = 0;

		return true;
	}

	T* new_data = new T[new_size];
	panic::uint_t copy_size = length;

	if (new_size < length){
		copy_size = new_size;
	}

	PANIC_OMP_PARALLEL_FOR_IF(copy_size > vector_omp_min_size)
	for (panic::uint_t i = 0; i < copy_size; ++i){
		new_data[i] = data[i];
	}

	PANIC_OMP_PARALLEL_FOR_IF(copy_size - new_size > vector_omp_min_size)
	for (panic::uint_t i = copy_size; i < new_size; ++i){
		new_data[i] = static_cast<T>(0);
	}

	delete[] data;

	data = new_data;
	length = new_size;

	return true;

}

//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::tensor::vector::fill
//
// Description:
//		Fills te vector with a value
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
bool vector<T>::fill(T value){
	PANIC_OMP_PARALLEL_FOR_IF(length > vector_omp_min_size)
	for (panic::uint_t i = 0; i < length; ++i){
		data[i] = value;
	}

	return true;
}

//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::tensor::vector::operator[]
//
// Description:
//		Lets you read and write v[index]
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
T& vector<T>::operator[](panic::uint_t index){
	return data[index];
}

//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::tensor::vector::operator[]
//
// Description:
//		Lets you read v[index] from a const vector
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
const T& vector<T>::operator[](panic::uint_t index) const{
	return data[index];
}

//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::tensor::vector::at
//
// Description:
//		Lets you read and write v.at(index) with index bounse
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
T& vector<T>::at(panic::uint_t index){

	if (index >= length){
		return data[length-1];
	}

	return data[index];
}

//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::tensor::vector::at
//
// Description:
//		Lets you read v[index] from a const vector with index bounse
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
const T& vector<T>::at(panic::uint_t index) const{
	if (index >= length){
		return data[length-1];
	}
	return data[index];
}



//---------------------------------------------------------------------------------------------------------------------------
// EXPLICIT TEMPLATE INSTANTIATION
//---------------------------------------------------------------------------------------------------------------------------

template struct vector<panic::real_t>;
template struct vector<panic::int_t>;
template struct vector<panic::uint_t>;


	} // namespace tensor
} // namespace panic