Files
panic/src/math/mean.cpp
T

317 lines
11 KiB
C++

/**++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
*
* 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 <math/mean.hpp>
#include <config/omp.hpp>
#include <tensor/vector.hpp> // for panic::vector
#include <tensor/matrix.hpp> // for panic::matrix
#include <math/sum.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 mean_omp_min_work = 500;
//---------------------------------------------------------------------------------------------------------------------------
// INPLEMENTATION
//---------------------------------------------------------------------------------------------------------------------------
namespace panic {
namespace math {
//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::math::mean
//
// Description:
// Find the mean value for a vector
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
T mean(const panic::tensor::vector<T>& a){
T sum = panic::math::sum(a);
return sum / static_cast<T>(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<panic::types::uint_t>(const panic::tensor::vector<panic::types::uint_t>& a
);
template panic::types::int_t mean<panic::types::int_t>(const panic::tensor::vector<panic::types::int_t>& a
);
template panic::types::real_t mean<panic::types::real_t>(const panic::tensor::vector<panic::types::real_t>& a
);
//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::math::mean
//
// Description:
// Find the mean value for a matrix
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
T mean(const panic::tensor::matrix<T>& 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<T>(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<panic::types::uint_t>(const panic::tensor::matrix<panic::types::uint_t>& a
);
template panic::types::int_t mean<panic::types::int_t>(const panic::tensor::matrix<panic::types::int_t>& a
);
template panic::types::real_t mean<panic::types::real_t>(const panic::tensor::matrix<panic::types::real_t>& a
);
//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::math::mean_rowwise
//
// Description:
// Find the mean row-wise of a matrix
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
bool mean_rowwise(const panic::tensor::matrix<T>& A, panic::tensor::vector<T>& 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<panic::types::uint_t>(const panic::tensor::matrix<panic::types::uint_t>& A,
panic::tensor::vector<panic::types::uint_t>& b
);
template bool mean_rowwise<panic::types::int_t>(const panic::tensor::matrix<panic::types::int_t>& A,
panic::tensor::vector<panic::types::int_t>& b
);
template bool mean_rowwise<panic::types::real_t>(const panic::tensor::matrix<panic::types::real_t>& A,
panic::tensor::vector<panic::types::real_t>& b
);
//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::math::mean_rowwise
//
// Description:
// Returns row-wise sum values
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
panic::tensor::vector<T> mean_rowwise(const panic::tensor::matrix<T>& A){
panic::tensor::vector<T> b;
if (!mean_rowwise(A, b)){
return panic::tensor::vector<T>();
}
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<panic::types::uint_t>
mean_rowwise<panic::types::uint_t>(const panic::tensor::matrix<panic::types::uint_t>& A
);
template panic::tensor::vector<panic::types::int_t>
mean_rowwise<panic::types::int_t>(const panic::tensor::matrix<panic::types::int_t>& A
);
template panic::tensor::vector<panic::types::real_t>
mean_rowwise<panic::types::real_t>(const panic::tensor::matrix<panic::types::real_t>& A
);
//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::math::mean_colwise
//
// Description:
// Find the mean column-wise of a matrix
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
bool mean_colwise(const panic::tensor::matrix<T>& A, panic::tensor::vector<T>& 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(cols) ){
return false;
}
if (! sum_colwise(A,b)){
return false;
}
// Each thread handles separate cols and writes to a separate b[i].
PANIC_OMP_PARALLEL_FOR_IF(work > mean_omp_min_work)
for (panic::types::uint_t i = 0; i < cols; ++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_colwise<panic::types::uint_t>(const panic::tensor::matrix<panic::types::uint_t>& A,
panic::tensor::vector<panic::types::uint_t>& b
);
template bool mean_colwise<panic::types::int_t>(const panic::tensor::matrix<panic::types::int_t>& A,
panic::tensor::vector<panic::types::int_t>& b
);
template bool mean_colwise<panic::types::real_t>(const panic::tensor::matrix<panic::types::real_t>& A,
panic::tensor::vector<panic::types::real_t>& b
);
//--------------------------------------------------------------------------------------------------------------------------
// Function Name : panic::math::mean_colwise
//
// Description:
// Returns column-wise mean values
//--------------------------------------------------------------------------------------------------------------------------
template <typename T>
panic::tensor::vector<T> mean_colwise(const panic::tensor::matrix<T>& A){
panic::tensor::vector<T> b;
if (!mean_colwise(A, b)){
return panic::tensor::vector<T>();
}
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<panic::types::uint_t>
mean_colwise<panic::types::uint_t>(const panic::tensor::matrix<panic::types::uint_t>& A
);
template panic::tensor::vector<panic::types::int_t>
mean_colwise<panic::types::int_t>(const panic::tensor::matrix<panic::types::int_t>& A
);
template panic::tensor::vector<panic::types::real_t>
mean_colwise<panic::types::real_t>(const panic::tensor::matrix<panic::types::real_t>& A
);
} // namespace math
} // namespace panic