- Aide de Scilab
- Optimisation et Simulation
- Optimization base
- optimbase_cget
- optimbase_checkbounds
- optimbase_checkcostfun
- optimbase_checkx0
- optimbase_configure
- optimbase_destroy
- optimbase_function
- optimbase_get
- optimbase_hasbounds
- optimbase_hasconstraints
- optimbase_hasnlcons
- optimbase_histget
- optimbase_histset
- optimbase_incriter
- optimbase_isfeasible
- optimbase_isinbounds
- optimbase_isinnonlincons
- optimbase_log
- optimbase_new
- optimbase_outputcmd
- optimbase_outstruct
- overview
- optimbase_proj2bnds
- optimbase_set
- optimbase_stoplog
- optimbase_terminate
Please note that the recommended version of Scilab is 2025.0.0. This page might be outdated.
See the recommended documentation of this function
overview
An overview of the Optimbase toolbox.
Purpose
The goal of this component is to provide a building block for optimization methods. The goal is to provide a building block for a large class of specialized optimization methods. This component manages
the number of variables,
the minimum and maximum bounds,
the number of non linear inequality constraints,
the cost function,
the logging system,
various termination criteria,
etc...
This toolboxes is designed with Oriented Object ideas in mind.
Features
The following is a list of features the Optimbase toolbox currently provides:
Manage cost function
optional additional argument,
direct communication of the task to perform: cost function or inequality constraints.
Manage various termination criteria, including
maximum number of iterations,
tolerance on function value (relative or absolute),
tolerance on x (relative or absolute),
maximum number of evaluations of cost function.
Manage the history of the convergence, including
history of function values,
history of optimum point.
Provide query features for
the status of the optimization process,
the number of iterations,
the number of function evaluations,
function value at initial point,
function value at optimal point,
the optimum parameters,
etc...
Description
This set of commands allows to manage an abstract optimization method. The goal is to provide a building block for a large class of specialized optimization methods. This component manages the number of variables, the minimum and maximum bounds, the number of non linear inequality constraints, the logging system, various termination criteria, the cost function, etc...
The optimization problem to solve is the following
min f(x) l_i <= x_i <= h_i, i = 1,n g_i(x) >= 0, i = 1,nbineq
where
- n
number of variables
- nbineq
number of inequality constraints
Example
In the following example, ones searches to solve f(x) = 0 thanks dichotomy method.
An optimization object is created and configured (number of variables, initial point,
maximum number of iterations, ...). The -verbose
option is enabled so that
messages are generated during the algorithm, are printed.
function [f, index]=fun(x, index) f = 2*x - 4; endfunction a = -5; b = 5; x0 = (a+b)/2; // Creation of the object opt = optimbase_new(); // Configures the object opt = optimbase_configure(opt,"-numberofvariables",2); opt = optimbase_configure(opt, "-x0", x0); opt = optimbase_configure(opt, "-tolxrelative", 10*%eps); opt = optimbase_configure(opt, "-maxiter", 30); opt = optimbase_configure(opt, "-function", fun); opt = optimbase_configure(opt,"-verbose",1); function x=Dicho(opt, a, b) xk = optimbase_cget(opt, "-x0"); [opt, fx0, index] = optimbase_function (opt , xk , 1); opt = optimbase_set ( opt , "-xopt" , xk ); opt = optimbase_set ( opt , "-fopt" , fx0 ); terminate = %f; while ~terminate [opt, f, index] = optimbase_function(opt, xk, 1); [opt, g, index] = optimbase_function(opt, a, 1); if g*f <= 0 then b = xk; else a = xk; end x = (a + b)/2; opt = optimbase_incriter(opt); [opt, terminate, status] = optimbase_terminate(opt, optimbase_get(opt, "-fopt"), f, xk, x); opt = optimbase_set ( opt , "-xopt" , x ); opt = optimbase_set ( opt , "-fopt" , f ); xk = x; end endfunction x = Dicho(opt,a,b)
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