/**++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 *
 *                                              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:         spiral_data.cpp
 * Revision:          0.1.0
 * Date:              29-07-2026
 * Author:            Michelle Bausager
 *
 * Description:
 * Functions to generate dataset for neural networks;
 *
 *++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/
#include <neural_network/datasets/spiral_data.hpp>

#include <tensor/vector.hpp>
#include <tensor/matrix.hpp>
#include <config/types.hpp>
#include <config/omp.hpp>


#include <math/trigonometry/sin.hpp>
#include <math/trigonometry/cos.hpp>
#include <math/add.hpp>
#include <random/uniform.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 spiral_data_omp_min_work = 500;
//---------------------------------------------------------------------------------------------------------------------------

//---------------------------------------------------------------------------------------------------------------------------
// INPLEMENTATION
//---------------------------------------------------------------------------------------------------------------------------

namespace panic {
	namespace neural_network {


//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::neural_network::spiral_data
//
// Description:
//		Generates dataset with spiral data
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
bool spiral_data(const panic::types::uint_t samples, const panic::types::uint_t classes, panic::tensor::matrix<T>& X, panic::tensor::uint_vector& y){


	if ( !X.resize(samples*classes, 2) || !y.resize(samples*classes) ){
		return false;
	}

	PANIC_OMP_PARALLEL_FOR_IF(samples*classes > spiral_data_omp_min_work)
	for (panic::types::uint_t i = 0; i < classes; ++i){
		for (panic::types::uint_t j = 0; j < samples; ++j){

			const T radius = static_cast<T>(j)/static_cast<T>(samples-1);

			const T angle = static_cast<T>(i)*T{4} + (T{4}*radius);

			const panic::types::uint_t row_index = (i*samples) + j;

			X(row_index, 0) = radius*panic::math::cos(angle*T{2.5});
			X(row_index, 1) = radius*panic::math::sin(angle*T{2.5});

			y[row_index] = i;
		}
	}

	panic::tensor::matrix<T> random_matrix(samples*classes, 2);
	panic::random::uniform(random_matrix, T{-0.0015}, T{0.0015});
	
	if (!panic::math::add(X, random_matrix, X)){
		return false;
	}
	

	return true;

}
//--------------------------------------------------------------------------------------------------------------------------
// EXPLICIT TEMPLATE INSTANTIATION
//
// The implementation is in this .cpp file.
// Build the overload for the official PANIC numeric types.
//--------------------------------------------------------------------------------------------------------------------------
template bool spiral_data<panic::types::real_t>(const panic::types::uint_t samples, 
												const panic::types::uint_t classes, 
												panic::tensor::matrix<panic::types::real_t>& X, 
												panic::tensor::uint_vector& y
);


	} // namespace neural_network
} // namespace panic