559 lines
26 KiB
C++
559 lines
26 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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* 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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#ifndef _GCTL_LBFGS_H
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#define _GCTL_LBFGS_H
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#include "gctl/core.h"
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#include "gctl/maths.h"
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#include "gctl/algorithm.h"
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#include "gctl_optimization_config.h"
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#ifdef GCTL_OPTIMIZATION_TOML
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#include "toml.hpp"
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#endif // GCTL_OPTIMIZATION_TOML
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#if defined _WINDOWS || __WIN32__
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#include "windows.h"
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#endif // _WINDOWS || __WIN32__
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namespace gctl
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{
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/**
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* @brief Return value of the lbfgs() function. Roughly speaking, a negative value indicates an error.
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*/
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enum lbfgs_return_code
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{
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/** L-BFGS reaches convergence. */
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LBFGS_EPS_CONVERGENCE = 0,
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LBFGS_DELTA_CONVERGENCE,
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LBFGS_RESI_CONVERGENCE,
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LBFGS_STOP, //1
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/** The initial variables already minimize the objective function. */
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LBFGS_ALREADY_MINIMIZED, //2
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/** Unknown error. */
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LBFGSERR_UNKNOWNERROR = -1024,
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/** Logic error. */
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LBFGSERR_LOGICERROR, //-1023
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/** Insufficient memory. */
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LBFGSERR_OUTOFMEMORY, //-1022
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/** The minimization process has been canceled. */
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LBFGSERR_CANCELED,
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/** Invalid number of variables specified. */
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LBFGSERR_INVALID_N,
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/** Invalid number of variables (for SSE) specified. */
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LBFGSERR_INVALID_N_SSE,
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/** The array x must be aligned to 16 (for SSE). */
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LBFGSERR_INVALID_X_SSE,
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/** Invalid parameter lbfgs_para::epsilon specified. */
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LBFGSERR_INVALID_EPSILON,
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/** Invalid parameter lbfgs_para::past specified. */
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LBFGSERR_INVALID_TESTPERIOD,
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/** Invalid parameter lbfgs_para::delta specified. */
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LBFGSERR_INVALID_DELTA,
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/** Invalid parameter lbfgs_para::linesearch specified. */
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LBFGSERR_INVALID_LINESEARCH,
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/** Invalid parameter lbfgs_para::max_step specified. */
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LBFGSERR_INVALID_MINSTEP,
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/** Invalid parameter lbfgs_para::max_step specified. */
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LBFGSERR_INVALID_MAXSTEP,
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/** Invalid parameter lbfgs_para::ftol specified. */
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LBFGSERR_INVALID_FTOL,
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/** Invalid parameter lbfgs_para::wolfe specified. */
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LBFGSERR_INVALID_WOLFE,
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/** Invalid parameter lbfgs_para::gtol specified. */
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LBFGSERR_INVALID_GTOL,
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/** Invalid parameter lbfgs_para::xtol specified. */
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LBFGSERR_INVALID_XTOL,
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/** Invalid parameter lbfgs_para::max_linesearch specified. */
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LBFGSERR_INVALID_MAXLINESEARCH,
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/** Invalid parameter lbfgs_para::orthantwise_c specified. */
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LBFGSERR_INVALID_ORTHANTWISE,
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/** Invalid parameter lbfgs_para::orthantwise_start specified. */
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LBFGSERR_INVALID_ORTHANTWISE_START,
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/** Invalid parameter lbfgs_para::orthantwise_end specified. */
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LBFGSERR_INVALID_ORTHANTWISE_END,
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/** The line-search step went out of the interval of uncertainty. */
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LBFGSERR_OUTOFINTERVAL,
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/** A logic error occurred; alternatively, the interval of uncertainty
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became too small. */
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LBFGSERR_INCORRECT_TMINMAX,
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/** A rounding error occurred; alternatively, no line-search step
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satisfies the sufficient decrease and curvature conditions. */
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LBFGSERR_ROUNDING_ERROR,
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/** The line-search step became smaller than lbfgs_para::min_step. */
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LBFGSERR_MINIMUMSTEP,
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/** The line-search step became larger than lbfgs_para::max_step. */
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LBFGSERR_MAXIMUMSTEP,
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/** The line-search routine reaches the maximum number of evaluations. */
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LBFGSERR_MAXIMUMLINESEARCH,
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/** The algorithm routine reaches the maximum number of iterations. */
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LBFGSERR_MAXIMUMITERATION,
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/** Relative width of the interval of uncertainty is at most
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lbfgs_para::xtol. */
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LBFGSERR_WIDTHTOOSMALL,
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/** A logic error (negative line-search step) occurred. */
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LBFGSERR_INVALIDPARAMETERS,
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/** The current search direction increases the objective function value. */
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LBFGSERR_INCREASEGRADIENT,
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};
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// 枚举类型 线性搜索方法
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// 0 MoreThuente方法
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// 1 Armijo条件方法
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// 2 标准Wolfe条件方法
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// 3 增强Wolfe条件方法
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/**
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* @brief Line search algorithms.
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*/
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enum line_search_type
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{
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/** The default algorithm (MoreThuente method). */
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LBFGS_LINESEARCH_DEFAULT = 0,
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/** MoreThuente method proposd by More and Thuente. */
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LBFGS_LINESEARCH_MORETHUENTE = 0,
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/**
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* Backtracking method with the Armijo condition.
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* The backtracking method finds the step length such that it satisfies
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* the sufficient decrease (Armijo) condition,
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* - f(x + a * d) <= f(x) + lbfgs_para::ftol * a * g(x)^T d,
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*
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* where x is the current point, d is the current search direction, and
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* a is the step length.
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*/
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LBFGS_LINESEARCH_BACKTRACKING_ARMIJO = 1,
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/** The backtracking method with the defualt (regular Wolfe) condition. */
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LBFGS_LINESEARCH_BACKTRACKING = 2,
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/**
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* Backtracking method with regular Wolfe condition.
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* The backtracking method finds the step length such that it satisfies
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* both the Armijo condition (LBFGS_LINESEARCH_BACKTRACKING_ARMIJO)
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* and the curvature condition,
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* - g(x + a * d)^T d >= lbfgs_para::wolfe * g(x)^T d,
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*
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* where x is the current point, d is the current search direction, and
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* a is the step length.
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*/
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LBFGS_LINESEARCH_BACKTRACKING_WOLFE = 2,
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/**
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* Backtracking method with strong Wolfe condition.
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* The backtracking method finds the step length such that it satisfies
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* both the Armijo condition (LBFGS_LINESEARCH_BACKTRACKING_ARMIJO)
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* and the following condition,
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* - |g(x + a * d)^T d| <= lbfgs_para::wolfe * |g(x)^T d|,
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*
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* where x is the current point, d is the current search direction, and
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* a is the step length.
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*/
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LBFGS_LINESEARCH_BACKTRACKING_STRONG_WOLFE = 3,
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LBFGS_LINESEARCH_BACKTRACKING_ARMIJO_QUAD = 4,
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//LBFGS_LINESEARCH_BACKTRACKING_QUAD = 5,
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//LBFGS_LINESEARCH_BACKTRACKING_WOLFE_QUAD = 5,
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//LBFGS_LINESEARCH_BACKTRACKING_STRONG_WOLFE_QUAD = 6,
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};
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// L-BFGS参数类型。参数很多，简要说明如下：
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// m L-BFGS算法中储存的前序sk与yk向量个数，这个值控制了算法使用的内存多少，默认值为6（不建议小于3的值），值多大近似精度越高，计算量也越大。
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// epsilon 迭代的终止精度，默认值为1e-5
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// past 以delta(不同迭代次数的目标函数值)为基础的迭代终止条件数，past代表了以多少迭代次数之前的目标函数值作为delta计算的间隔，默认值为0，
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// 即不以delta为迭代终止条件。
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// delta (f' - f) / f 不同迭代次数时目标函数之差与当前目标函数值之比，但past不为0时会计算。
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// max_iterations 最大迭代次数，为0时表示一直迭代到终止条件被满足或出现其他错误。
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// linesearch 线性搜索方式，由此文件前述枚举类型定义。
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// max_linesearch 每次迭代中线性搜索的最大次数，默认值为40
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// min_step 线性搜索中的最小步长，默认值为1e-20
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// max_step 线性搜索中的最大步长，默认值为1e+20
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// ftol 线性搜索的精度值，默认值为1e-4，取值范围（0-0.5）。
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// wolfe Wolfe线性搜索中的控制参数，默认值为0.9，大于ftol小于1.0
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// gtol 线性搜索中的控制参数，默认值为0.9，大于ftol小于1.0
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// xtol 浮点数精度，默认值为1e-16
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// orthantwise_c 模型参数x的L1模的乘积参数，默认值为0.0，此时算法即为L2模形式，当此参数大于0时，算法即为OWL-QN
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// orthantwise_start 开始计算模型参数x的L1模的迭代序号
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// orthantwise_end 终止计算模型参数x的L1模的迭代序号
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/**
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* L-BFGS optimization parameters.
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* Call lbfgs_parameter_init() function to initialize parameters to the
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* default values.
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*/
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struct lbfgs_para
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{
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/**
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* The number of corrections to approximate the inverse hessian matrix.
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* The L-BFGS routine stores the computation results of previous \ref m
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* iterations to approximate the inverse hessian matrix of the current
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* iteration. This parameter controls the size of the limited memories
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* (corrections). The default value is \c 6. Values less than \c 3 are
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* not recommended. Large values will result in excessive computing time.
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*/
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int m;
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/**
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* Epsilon for convergence test.
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* This parameter determines the accuracy with which the solution is to
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* be found. A minimization terminates when
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* ||g|| < \ref epsilon * max(1, ||x||),
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* where ||.|| denotes the Euclidean (L2) norm. The default value is
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* \c 1e-5.
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*/
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double epsilon;
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/**
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* Distance for delta-based convergence test.
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* This parameter determines the distance, in iterations, to compute
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* the rate of decrease of the objective function. If the value of this
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* parameter is zero, the library does not perform the delta-based
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* convergence test. The default value is \c 0.
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*/
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int past;
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/**
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* Delta for convergence test.
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* This parameter determines the minimum rate of decrease of the
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* objective function. The library stops iterations when the
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* following condition is met:
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* (f' - f) / f < \ref delta,
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* where f' is the objective value of \ref past iterations ago, and f is
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* the objective value of the current iteration.
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* The default value is \c 1e-5.
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*/
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double delta;
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/**
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* Residual for convergence test.
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* This parameter determines the accuracy with which the solution is to
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* be found. A minimization terminates when
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* f(x) <= residual,
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* The default value is \c 1e-8.
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*
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*/
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double residual;
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/**
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* The maximum number of iterations.
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* The lbfgs() function terminates an optimization process with
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* ::LBFGSERR_MAXIMUMITERATION status code when the iteration count
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* exceedes this parameter. Setting this parameter to zero continues an
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* optimization process until a convergence or error. The default value
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* is \c 0.
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*/
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int max_iterations;
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/**
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* The line search algorithm.
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* This parameter specifies a line search algorithm to be used by the
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* L-BFGS routine.
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*/
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int linesearch;
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/**
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* The maximum number of trials for the line search.
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* This parameter controls the number of function and gradients evaluations
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* per iteration for the line search routine. The default value is \c 40.
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*/
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int max_linesearch;
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/**
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* The minimum step of the line search routine.
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* The default value is \c 1e-20. This value need not be modified unless
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* the exponents are too large for the machine being used, or unless the
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* problem is extremely badly scaled (in which case the exponents should
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* be increased).
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*/
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double min_step;
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/**
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* The maximum step of the line search.
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* The default value is \c 1e+20. This value need not be modified unless
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* the exponents are too large for the machine being used, or unless the
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* problem is extremely badly scaled (in which case the exponents should
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* be increased).
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*/
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double max_step;
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/**
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* A parameter to control the accuracy of the line search routine.
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* The default value is \c 1e-4. This parameter should be greater
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* than zero and smaller than \c 0.5.
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*/
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double ftol;
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/**
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* A coefficient for the Wolfe condition.
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* This parameter is valid only when the backtracking line-search
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* algorithm is used with the Wolfe condition,
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* ::LBFGS_LINESEARCH_BACKTRACKING_STRONG_WOLFE or
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* ::LBFGS_LINESEARCH_BACKTRACKING_WOLFE .
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* The default value is \c 0.9. This parameter should be greater
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* the \ref ftol parameter and smaller than \c 1.0.
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*/
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double wolfe;
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/**
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* A parameter to control the accuracy of the line search routine.
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* The default value is \c 0.9. If the function and gradient
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* evaluations are inexpensive with respect to the cost of the
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* iteration (which is sometimes the case when solving very large
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* problems) it may be advantageous to set this parameter to a small
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* value. A typical small value is \c 0.1. This parameter shuold be
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* greater than the \ref ftol parameter (\c 1e-4) and smaller than
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* \c 1.0.
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*/
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double gtol;
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/**
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* The machine precision for floating-point values.
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* This parameter must be a positive value set by a client program to
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* estimate the machine precision. The line search routine will terminate
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* with the status code (::LBFGSERR_ROUNDING_ERROR) if the relative width
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* of the interval of uncertainty is less than this parameter.
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*/
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double xtol;
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/**
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* Coeefficient for the L1 norm of variables.
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* This parameter should be set to zero for standard minimization
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* problems. Setting this parameter to a positive value activates
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* Orthant-Wise Limited-memory Quasi-Newton (OWL-QN) method, which
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* minimizes the objective function F(x) combined with the L1 norm |x|
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* of the variables, {F(x) + C |x|}. This parameter is the coeefficient
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* for the |x|, i.e., C. As the L1 norm |x| is not differentiable at
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* zero, the library modifies function and gradient evaluations from
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* a client program suitably; a client program thus have only to return
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* the function value F(x) and gradients G(x) as usual. The default value
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* is zero.
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*/
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double orthantwise_c;
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/**
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* Start index for computing L1 norm of the variables.
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* This parameter is valid only for OWL-QN method
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* (i.e., \ref orthantwise_c != 0). This parameter b (0 <= b < N)
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* specifies the index number from which the library computes the
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* L1 norm of the variables x,
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* |x| := |x_{b}| + |x_{b+1}| + ... + |x_{N}| .
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* In other words, variables x_1, ..., x_{b-1} are not used for
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* computing the L1 norm. Setting b (0 < b < N), one can protect
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* variables, x_1, ..., x_{b-1} (e.g., a bias term of logistic
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* regression) from being regularized. The default value is zero.
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*/
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int orthantwise_start;
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/**
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* End index for computing L1 norm of the variables.
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* This parameter is valid only for OWL-QN method
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* (i.e., \ref orthantwise_c != 0). This parameter e (0 < e <= N)
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* specifies the index number at which the library stops computing the
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* L1 norm of the variables x,
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*/
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int orthantwise_end;
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};
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class lbfgs_solver
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{
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private:
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lbfgs_para lbfgs_param_; ///< lbfgs 算法参数
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bool lbfgs_silent_; ///< 显示运行信息
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// 算法函数是私有的，不能直接使用，通过Minimize函数调用
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// 下面是L-BFGS的主函数，各个参数的说明简要翻译如下：
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// n 数组的长度，也就是待求的模型参数的数量
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// x 模型参数数组的指针，函数通过指针直接操作模型数组，所以不需要返回计算结果。一开始赋给函数的数组即为
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// 初始模型，函数结束后即为最优化结果
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// ptr_fx 目标函数的值的指针，设计成指针可以方便在函数外部监控迭代过程的收敛情况
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// retval 返回值。无错即为0，非0值代表此文件上部枚举类型中的对应错误。此文件下部定义的错误信息显示即利用此返回值与
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// 预定义的枚举类型输出相应的错误信息。
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/**
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* Start a L-BFGS optimization.
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*
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* @param x The array of variables. A client program can set
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* default values for the optimization and receive the
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* optimization result through this array. This array
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* must be allocated by ::lbfgs_malloc function
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* for libLBFGS built with SSE/SSE2 optimization routine
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* enabled. The library built without SSE/SSE2
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* optimization does not have such a requirement.
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* @param ptr_fx The pointer to the variable that receives the final
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* value of the objective function for the variables.
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* This argument can be set to \c NULL if the final
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* value of the objective function is unnecessary.
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* @retval The status code. This function returns zero if the
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* minimization process terminates without an error. A
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* non-zero value indicates an error.
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*/
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lbfgs_return_code lbfgs(array<double> &x, double &ptr_fx, std::ostream &ss);
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lbfgs_return_code lbfgs_preconditioned(array<double> &x, double &ptr_fx, std::ostream &ss);
|
||
|
||
// 线性搜索方法 内部私有函数 不能直接使用
|
||
lbfgs_return_code line_search_backtracking(int n, gctl::array<double> &x, double *f, gctl::array<double> &g, gctl::array<double> &s,
|
||
double *stp, const gctl::array<double> &xp, const gctl::array<double> &gp, gctl::array<double> &wp, int &ls);
|
||
lbfgs_return_code line_search_backtracking_quad(int n, gctl::array<double> &x, double *f, gctl::array<double> &g, gctl::array<double> &s,
|
||
double *stp, const gctl::array<double> &xp, const gctl::array<double> &gp, gctl::array<double> &wp, int &ls);
|
||
lbfgs_return_code line_search_backtracking_owlqn(int n, gctl::array<double> &x, double *f, gctl::array<double> &g, gctl::array<double> &s,
|
||
double *stp, const gctl::array<double> &xp, const gctl::array<double> &gp, gctl::array<double> &wp, int &ls);
|
||
lbfgs_return_code line_search_morethuente(int n, gctl::array<double> &x, double *f, gctl::array<double> &g, gctl::array<double> &s,
|
||
double *stp, const gctl::array<double> &xp, const gctl::array<double> &gp, gctl::array<double> &wa, int &ls);
|
||
|
||
// 显示lbfgs函数返回值信息 主要是错误信息
|
||
void lbfgs_error_str(lbfgs_return_code err_code, std::ostream &ss = std::clog, bool err_throw = false);
|
||
|
||
public:
|
||
lbfgs_solver();
|
||
virtual ~lbfgs_solver();
|
||
|
||
/**
|
||
* @brief 不显示运行信息，仅抛出运行错误。
|
||
*
|
||
*/
|
||
void lbfgs_silent();
|
||
|
||
/**
|
||
* @brief 设置算法参数。
|
||
*
|
||
* @param in_param 参数对象
|
||
*/
|
||
void set_lbfgs_para(const lbfgs_para &in_param);
|
||
|
||
#ifdef GCTL_OPTIMIZATION_TOML
|
||
/**
|
||
* @brief 设置算法参数。
|
||
*
|
||
* @param toml_data toml数据对象
|
||
*/
|
||
void set_lbfgs_para(const toml::value &toml_data);
|
||
#endif // GCTL_OPTIMIZATION_TOML
|
||
|
||
/**
|
||
* @brief 返回一个全为默认值的参数对象。
|
||
*
|
||
* @return lbfgs_para
|
||
*/
|
||
lbfgs_para default_lbfgs_para();
|
||
|
||
/**
|
||
* @brief 显示当前运行参数
|
||
*
|
||
* @param ss 标准输出流
|
||
*/
|
||
void show_lbfgs_para(std::ostream &ss = std::clog);
|
||
|
||
// 目标函数与其梯度值计算函数的接口，参数简要说明如下：
|
||
// x 当前的模型参数值的指针
|
||
// g 当前模型参数值对应的梯度指针
|
||
// step 当前线性搜索所使用的步长
|
||
// retval 当前模型参数的目标函数值
|
||
/**
|
||
* Callback interface to provide objective function and gradient evaluations.
|
||
*
|
||
* The lbfgs() function call this function to obtain the values of objective
|
||
* function and its gradients when needed. A client program must implement
|
||
* this function to evaluate the values of the objective function and its
|
||
* gradients, given current values of variables.
|
||
*
|
||
* @param x The current values of variables.
|
||
* @param g The gradient vector. The callback function must compute
|
||
* the gradient values for the current variables.
|
||
* @param step The current step of the line search routine.
|
||
* @retval double The value of the objective function for the current
|
||
* variables.
|
||
*/
|
||
virtual double LBFGS_Evaluate(const array<double> &x, array<double> &g) = 0;
|
||
|
||
/**
|
||
* Callback interface to implement the preconditioning process.
|
||
*
|
||
* The lbfgs() function call this function for each iteration. Implementing
|
||
* this function, a client program can preform the preconditioning process.
|
||
*
|
||
* @param x The current values of variables.
|
||
* @param g The current gradient values of variables.
|
||
* @param d The current values of search directions.
|
||
* @param d_pre The values of search directions being preconditioned.
|
||
* The callback function must compute these values.
|
||
*/
|
||
virtual void LBFGS_Precondition(const array<double> &x, const array<double> &g, const array<double> &d, array<double> &d_pre);
|
||
|
||
// 进程函数的接口，参数简要说明如下：
|
||
// x 当前的模型参数值的指针
|
||
// g 当前模型参数值对应的梯度指针
|
||
// fx 目标函数的值
|
||
// xnorm 模型参数数组的L2模长
|
||
// gnorm 模型梯度数组的L2模长
|
||
// step 当前线性搜索所使用的步长
|
||
// k 迭代的次数
|
||
// ls 此次迭代所使用的线性搜索次数
|
||
// retval 返回0则lbfgs()函数继续，否则终止
|
||
/**
|
||
* Callback interface to receive the progress of the optimization process.
|
||
*
|
||
* The lbfgs() function call this function for each iteration. Implementing
|
||
* this function, a client program can store or display the current progress
|
||
* of the optimization process.
|
||
*
|
||
* @param x The current values of variables.
|
||
* @param g The current gradient values of variables.
|
||
* @param fx The current value of the objective function.
|
||
* @param converge Current value of the convergence test.
|
||
* @param rate Current value of the delta-based convergence test.
|
||
* @param param 这是我们添加了一个指针以使用参数类型来监控迭代流程
|
||
* @param k The iteration count.
|
||
* @param ls The number of evaluations called for this iteration.
|
||
* @param ss Output stream object.
|
||
* @retval int Zero to continue the optimization process. Returning a
|
||
* non-zero value will cancel the optimization process.
|
||
*/
|
||
virtual int LBFGS_Progress(const array<double> &x, const array<double> &g, const double fx,
|
||
const double converge, const double rate, const lbfgs_para param, int k, int ls, std::ostream &ss);
|
||
|
||
/**
|
||
* @brief 调用算法执行最小化流程
|
||
*
|
||
* @param m 初始模型，最优化结果也保存在此数组内
|
||
* @param ss 信息的输出流
|
||
* @param err_throw 仅抛出错误
|
||
* @return double 最终的目标函数值
|
||
*/
|
||
double LBFGS_Minimize(array<double> &m, std::ostream &ss = std::clog, bool err_throw = false);
|
||
|
||
/**
|
||
* @brief 调用算法执行最小化流程
|
||
*
|
||
* @param m 初始模型，最优化结果也保存在此数组内
|
||
* @param ss 信息的输出流
|
||
* @param verbose 使用输出详细信息
|
||
* @param err_throw 仅抛出错误
|
||
* @return double 最终的目标函数值
|
||
*/
|
||
double LBFGS_MinimizePreconditioned(array<double> &m, std::ostream &ss = std::clog, bool err_throw = false);
|
||
};
|
||
}
|
||
|
||
#endif // _GCTL_LBFGS_H
|