gctl/lib/algorithm/multinary.cpp
2024-09-10 15:45:07 +08:00

123 lines
3.7 KiB
C++

/********************************************************
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* Geophysical Computational Tools & Library (GCTL)
*
* Copyright (c) 2023 Yi Zhang (yizhang-geo@zju.edu.cn)
*
* GCTL is distributed under a dual licensing scheme. You can redistribute
* it and/or modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation, either version 2
* of the License, or (at your option) any later version. You should have
* received a copy of the GNU Lesser General Public License along with this
* program. If not, see <http://www.gnu.org/licenses/>.
*
* If the terms and conditions of the LGPL v.2. would prevent you from using
* the GCTL, please consider the option to obtain a commercial license for a
* fee. These licenses are offered by the GCTL's original author. As a rule,
* licenses are provided "as-is", unlimited in time for a one time fee. Please
* send corresponding requests to: yizhang-geo@zju.edu.cn. Please do not forget
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******************************************************/
#include "multinary.h"
#define SQRT2PI 2.5066282746310002416
gctl::multinary::multinary(){}
gctl::multinary::multinary(double mini, double maxi, double std, unsigned int num)
{
init(mini, maxi, std, num);
}
gctl::multinary::multinary(const array<double> &xs, const array<double> &stds)
{
init(xs, stds);
}
gctl::multinary::~multinary(){}
void gctl::multinary::init(double mini, double maxi, double std, unsigned int num)
{
pnum_ = num - 1;
of_ = mini;
double dm = (maxi - of_)/(num - 1);
std_.resize(pnum_, std);
mp_.resize(pnum_);
ys_.resize(pnum_);
for (size_t i = 0; i < pnum_; i++)
{
mp_[i] = dm*(i+1);
}
ys_[0] = mp_[0];
for (size_t i = 1; i < pnum_; i++)
{
ys_[i] = mp_[i] - mp_[i-1];
}
return;
}
void gctl::multinary::init(const array<double> &xs, const array<double> &stds)
{
if (xs.size() - stds.size() != 1) throw std::runtime_error("[gctl::multinary] Invalid parameters' size.");
pnum_ = xs.size() - 1;
of_ = xs.front();
std_ = stds;
mp_.resize(pnum_);
ys_.resize(pnum_);
for (size_t i = 0; i < pnum_; i++)
{
mp_[i] = xs[i+1] - of_;
}
ys_[0] = mp_[0];
for (size_t i = 1; i < pnum_; i++)
{
ys_[i] = mp_[i] - mp_[i-1];
}
return;
}
double gctl::multinary::val(double x) const
{
//return GCTL_ZERO*(x - of_) + 0.5*Pm_(x - of_) + of_;
return 0.5*Pm_(x - of_) + of_;
}
double gctl::multinary::der(double x) const
{
//return GCTL_ZERO + Pm_grad_(x - of_);
return Pm_grad_(x - of_);
}
double gctl::multinary::Pm_(double x) const
{
double pm = 0;
for (size_t i = 0; i < pnum_; i++)
{
pm += ys_[i]*(1.0 + erf((x + 0.5*ys_[i] - mp_[i])/(M_SQRT2*std_[i])));
}
return pm;
}
double gctl::multinary::Pm_grad_(double x) const
{
double gm = 0;
for (size_t i = 0; i < pnum_; i++)
{
gm += exp(-1.0*(x + 0.5*ys_[i] - mp_[i])*(x + 0.5*ys_[i] - mp_[i])/(2.0*std_[i]*std_[i]))/(SQRT2PI*std_[i]);
}
return gm;
}