/**++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ * * 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: mean.cpp * Revision: 0.1.0 * Date: 30-07-2026 * Author: Michelle Bausager * * Description: * Functions to calculate mean of tensor arrays * *++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/ //--------------------------------------------------------------------------------------------------------------------------- // INCLUDE DESCRIPTION //----------------------------------------------------------------------------------------------------- #include

#include #include // for panic::vector
#include // for panic::matrix

#include //---------------------------------------------------------------------------------------------------------------------------
// 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 mean_omp_min_work = 500;
//---------------------------------------------------------------------------------------------------------------------------
// INPLEMENTATION
//---------------------------------------------------------------------------------------------------------------------------

namespace panic {
	namespace math {


//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::math::mean
//
// Description:
//		Find the mean value for a vector
//--------------------------------------------------------------------------------------------------------------------------
template T mean(const panic::tensor::vector & a){

	T sum = panic::math::sum(a);

	return sum / static_cast (a.size());
}
//--------------------------------------------------------------------------------------------------------------------------
// EXPLICIT TEMPLATE INSTANTIATION
//
// The implementation is in this .cpp file.
// Build the overload for the official PANIC numeric types.
//--------------------------------------------------------------------------------------------------------------------------
template panic::types::uint_t mean (const panic::tensor::vector & a
);
template panic::types::int_t mean (const panic::tensor::vector & a
);
template panic::types::real_t mean (const panic::tensor::vector & a
);



//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::math::mean
//
// Description:
//		Find the mean value for a matrix
//--------------------------------------------------------------------------------------------------------------------------
template T mean(const panic::tensor::matrix & A){

	panic::types::uint_t rows = A.rows();
	panic::types::uint_t cols = A.cols();
	panic::types::uint_t work = rows*cols;

	T sum = panic::math::sum(A);

	return sum / static_cast (work);
}
//--------------------------------------------------------------------------------------------------------------------------
// EXPLICIT TEMPLATE INSTANTIATION
//
// The implementation is in this .cpp file.
// Build the overload for the official PANIC numeric types.
//--------------------------------------------------------------------------------------------------------------------------
template panic::types::uint_t mean (const panic::tensor::matrix & a
);
template panic::types::int_t mean (const panic::tensor::matrix & a
);
template panic::types::real_t mean (const panic::tensor::matrix & a
);





//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::math::mean_rowwise
//
// Description:
//		Find the mean row-wise of a matrix
//--------------------------------------------------------------------------------------------------------------------------
template bool mean_rowwise(const panic::tensor::matrix & A, panic::tensor::vector & b){

	panic::types::uint_t rows = A.rows();
	panic::types::uint_t cols = A.cols();
	panic::types::uint_t work = rows*cols;

	if ( !b.resize(rows) ){
		return false;
	}

	if (!sum_rowwise(A, b)){
		return false;
	}
	

	// Each thread handles separate rows and writes to a separate b[i].
	PANIC_OMP_PARALLEL_FOR_IF(rows > mean_omp_min_work)
	for (panic::types::uint_t i = 0; i < rows; ++i){
		b[i] /= cols;
		
	}

	return true;
}
//--------------------------------------------------------------------------------------------------------------------------
// EXPLICIT TEMPLATE INSTANTIATION
//
// The implementation is in this .cpp file.
// Build the overload for the official PANIC numeric types.
//--------------------------------------------------------------------------------------------------------------------------
template bool mean_rowwise (const panic::tensor::matrix & A, 
							panic::tensor::vector & b
);
template bool mean_rowwise (const panic::tensor::matrix & A, 
							panic::tensor::vector & b
);
template bool mean_rowwise (const panic::tensor::matrix & A, 
							panic::tensor::vector & b
);




//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::math::mean_rowwise
//
// Description:
//		Returns row-wise sum values
//--------------------------------------------------------------------------------------------------------------------------
template panic::tensor::vector mean_rowwise(const panic::tensor::matrix & A){
	panic::tensor::vector b;

	if (!mean_rowwise(A, b)){
		return panic::tensor::vector ();
	}

	return b;
}
//--------------------------------------------------------------------------------------------------------------------------
// EXPLICIT TEMPLATE INSTANTIATION
//
// The implementation is in this .cpp file.
// Build the overload for the official PANIC numeric types.
//--------------------------------------------------------------------------------------------------------------------------
template panic::tensor::vector mean_rowwise (const panic::tensor::matrix & A
);
template panic::tensor::vector mean_rowwise (const panic::tensor::matrix & A
);
template panic::tensor::vector mean_rowwise (const panic::tensor::matrix & A
);


























//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::math::mean_colwise
//
// Description:
//		Find the mean column-wise of a matrix
//--------------------------------------------------------------------------------------------------------------------------
template bool mean_colwise(const panic::tensor::matrix & A, panic::tensor::vector