82 lines
3.1 KiB
C++
82 lines
3.1 KiB
C++
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/********************************************************
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* ██████╗ ██████╗████████╗██╗
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* ██╔════╝ ██╔════╝╚══██╔══╝██║
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* ██║ ███╗██║ ██║ ██║
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* ██║ ██║██║ ██║ ██║
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* ╚██████╔╝╚██████╗ ██║ ███████╗
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* ╚═════╝ ╚═════╝ ╚═╝ ╚══════╝
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* Geophysical Computational Tools & Library (GCTL)
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*
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* Copyright (c) 2022 Yi Zhang (yizhang-geo@zju.edu.cn)
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*
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* GCTL is distributed under a dual licensing scheme. You can redistribute
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* it and/or modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation, either version 2
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* of the License, or (at your option) any later version. You should have
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* received a copy of the GNU Lesser General Public License along with this
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* program. If not, see <http://www.gnu.org/licenses/>.
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*
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* If the terms and conditions of the LGPL v.2. would prevent you from using
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* the GCTL, please consider the option to obtain a commercial license for a
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* fee. These licenses are offered by the GCTL's original author. As a rule,
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* licenses are provided "as-is", unlimited in time for a one time fee. Please
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* send corresponding requests to: yizhang-geo@zju.edu.cn. Please do not forget
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* to include some description of your company and the realm of its activities.
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* Also add information on how to contact you by electronic and paper mail.
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******************************************************/
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#include "activation_sigmoid.h"
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gctl::sigmoid::sigmoid() {}
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gctl::sigmoid::~sigmoid() {}
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void gctl::sigmoid::activate(const matrix<double> &z, matrix<double> &a)
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{
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// a = activation(z) = 1 / (1 + exp(-z))
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// Z = [z1, ..., zn], A = [a1, ..., an], n observations
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a.resize(z.row_size(), z.col_size());
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int i, j;
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#pragma omp parallel for private (i, j) schedule(guided)
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for (i = 0; i < a.row_size(); i++)
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{
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for (j = 0; j < a.col_size(); j++)
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{
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a[i][j] = 1.0/(1.0 + exp(-1.0*z[i][j]));
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}
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}
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return;
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}
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void gctl::sigmoid::apply_jacobian(const matrix<double> &z,
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const matrix<double> &a, const matrix<double> &f, matrix<double> &g)
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{
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// Apply the Jacobian matrix J to a vector f
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// J = d_a / d_z = diag(a .* (1 - a))
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// g = J * f = a .* (1 - a) .* f
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// Z = [z1, ..., zn], G = [g1, ..., gn], F = [f1, ..., fn]
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// Note: When entering this function, Z and G may point to the same matrix
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g.resize(a.row_size(), a.col_size());
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int i, j;
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#pragma omp parallel for private (i, j) schedule(guided)
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for (i = 0; i < g.row_size(); i++)
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{
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for (j = 0; j < g.col_size(); j++)
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{
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g[i][j] = a[i][j]*(1.0 - a[i][j])*f[i][j];
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}
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}
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return;
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}
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std::string gctl::sigmoid::activation_name() const
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{
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return "Sigmoid";
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}
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gctl::activation_type_e gctl::sigmoid::activation_type() const
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{
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return Sigmoid;
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}
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