/**++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 *
 *                                              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:       tensor
 * File Name:         matrix.cpp
 * Revision:          0.1.0
 * Date:              23-06-2026
 * Author:            Michelle Bausager
 *
 * Description:
 * Defines the matrix object that will be used in the rest of the libraries.
 *
 *++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/

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

//---------------------------------------------------------------------------------------------------------------------------
// PRIVATE CONSTANTS
//---------------------------------------------------------------------------------------------------------------------------
/**
 * @brief Minimum number of element operations before using the OpenMP-enabled loop.
 *
 * Small vectors and matrices are kept serial because the overhead of starting
 * worker threads can be larger than the work itself.
 */
static const panic::types::uint_t matrix_omp_min_size = 500;

namespace panic{
	namespace tensor{


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

//--------------------------------------------------------------------------------------------------------------------------
// Constructor Name : panic::tensor::matrix::matrix
//
// Description:
//		Creates a matrix with size allocation and initializes all values to zero.
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
matrix<T>::matrix(panic::types::uint_t rows, panic::types::uint_t cols){
	n = rows;
	m = cols;
	length = n*m;

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

	data = new T[length];

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

}

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

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

	data = new T[length];

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

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

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

	data = new T[length];

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

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

	data = 0;
	n = 0;
	m = 0;
	length = 0;
}

//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::tensor::matrix::operator=
//
// Description:
//		Copy-assignment. Copies from another matrix.
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
matrix<T>& matrix<T>::operator=(const matrix& 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(other.length > matrix_omp_min_size)
		for (panic::types::uint_t i = 0; i < other.length; ++i){
			new_data[i] = other.data[i];
		}
	}

	delete[] data;

	data = new_data;
	n = other.n;
	m = other.m;
	length = other.length;

	return *this;
}

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

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

//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::tensor::matrix::resize
//
// Description:
//		Resizes the matrix to new dimentions and keeps old values
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
bool matrix<T>::resize(panic::types::uint_t new_n, panic::types::uint_t new_m){

	if ((new_n == n) && (new_m == m)){
		return true;
	}

	if ((new_n == 0) || (new_m == 0)){
		delete[] data;
		n = 0;
		m = 0;
		length = 0;
		data = 0;
		
		return true;
	}

	panic::types::uint_t new_length = new_n*new_m;

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

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

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

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

	delete[] data;

	data = new_data;
	n = new_n;
	m = new_m;
	length = new_length;

	return true;

}

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

	return true;
}

//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::tensor::matrix::operator()
//
// Description:
//		Lets you read and write A(2,3)
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
T& matrix<T>::operator()(panic::types::uint_t index_n, panic::types::uint_t index_m){
	return data[index_n*m + index_m];
}


//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::tensor::matrix::operator[]
//
// Description:
//		Lets you read A(2,3) from a const matrix
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
const T& matrix<T>::operator()(panic::types::uint_t index_n, panic::types::uint_t index_m) const{
	return data[index_n*m + index_m];
}


//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::tensor::matrix::set_row
//
// Description:
//		Filles and set a row to a value.
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
bool matrix<T>::set_row(const panic::types::uint_t index_row, const T c){

	PANIC_OMP_PARALLEL_FOR_IF(m > matrix_omp_min_size)
	for (panic::types::uint_t i = 0; i < m; ++i){
		data[index_row*m + i] = c;
	}

	return true;
}


//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::tensor::matrix::set_row
//
// Description:
//		Filles and set a row to a vector.
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
bool matrix<T>::set_row(const panic::types::uint_t index_row, const panic::tensor::vector<T> v){

	if (m != v.size()){
		return false;
	}

	PANIC_OMP_PARALLEL_FOR_IF(m > matrix_omp_min_size)
	for (panic::types::uint_t i = 0; i < m; ++i){
		data[index_row*m + i] = v[i];
	}

	return true;
}

//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::tensor::matrix::set_col
//
// Description:
//		Filles and set a column to a value.
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
bool matrix<T>::set_col(const panic::types::uint_t index_col, const T c){

	PANIC_OMP_PARALLEL_FOR_IF(n > matrix_omp_min_size)
	for (panic::types::uint_t i = 0; i < n; ++i){
		data[i*m + index_col] = c;
	}

	return true;
}


//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::tensor::matrix::set_col
//
// Description:
//		Filles and set a colmn to a vector.
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
bool matrix<T>::set_col(const panic::types::uint_t index_col, const panic::tensor::vector<T> v){

	if (n != v.size()){
		return false;
	}

	PANIC_OMP_PARALLEL_FOR_IF(n > matrix_omp_min_size)
	for (panic::types::uint_t i = 0; i < n; ++i){
		data[i*m + index_col] = v[i];
	}

	return true;
}




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

template struct matrix<panic::types::real_t>;
template struct matrix<panic::types::int_t>;
template struct matrix<panic::types::uint_t>;


	} // namespace tensor
} // namespace panic