NLopt

https://nlopt.readthedocs.io/en/latest/
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### Install NLopt with sudo make install

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Installation

Install the NLopt libraries and header files after building. By default installs libnlopt.so in /usr/local/lib and nlopt.h in /usr/local/include, plus manual pages and other files.

```bash
sudo make install

```

--------------------------------

### Install NLopt with cmake

Source: https://nlopt.readthedocs.io/en/latest

Standard build and installation procedure for NLopt on Unix-like systems with a C compiler. Run from the NLopt source directory.

```bash
cmake . && make && sudo make install
```

--------------------------------

### Set and get initial step in Guile: nlopt-opt-set-initial-step and nlopt-opt-get-initial-step

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Guile_Reference

Sets or gets the initial step sizes for derivative-free optimization algorithms. dx can be a vector or list of nonzero initial steps per dimension, or a single number for all dimensions. nlopt-opt-get-initial-step returns the initial step vector used for a starting guess of x in (nlopt-opt-optimize opt x).

```guile
(nlopt-opt-set-initial-step opt dx)
(nlopt-opt-get-initial-step opt x)
```

--------------------------------

### Install NLopt to custom directory with CMAKE_INSTALL_PREFIX

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Installation

Install NLopt into a custom directory using the CMAKE_INSTALL_PREFIX variable. Creates directories like $HOME/install/lib and installs NLopt there. Also changes where Python plugins are installed, so you may need to set PYTHONPATH.

```bash
cmake -DCMAKE_INSTALL_PREFIX=$HOME/install ..
make
make install

```

--------------------------------

### NLopt Optimization Example in Python

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Tutorial

A complete example demonstrating how to define an objective function, add inequality constraints, and run an optimization using the NLopt Python interface.

```python
import nlopt
from numpy import *
def myfunc(x, grad):
    if grad.size > 0:
        grad[0] = 0.0
        grad[1] = 0.5 / sqrt(x[1])
    return sqrt(x[1])
def myconstraint(x, grad, a, b):
    if grad.size > 0:
        grad[0] = 3 * a * (a*x[0] + b)**2
        grad[1] = -1.0
    return (a*x[0] + b)**3 - x[1]
opt = nlopt.opt(nlopt.LD_MMA, 2)
opt.set_lower_bounds([-float('inf'), 0])
opt.set_min_objective(myfunc)
opt.add_inequality_constraint(lambda x,grad: myconstraint(x,grad,2,0), 1e-8)
opt.add_inequality_constraint(lambda x,grad: myconstraint(x,grad,-1,1), 1e-8)
opt.set_xtol_rel(1e-4)
x = opt.optimize([1.234, 5.678])
minf = opt.last_optimum_value()
print("optimum at  ", x[0], x[1])
print("minimum value =  ", minf)
print("result code =  ", opt.last_optimize_result())
```

--------------------------------

### Compile program with custom NLopt install

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Installation

Compile a program against a custom NLopt installation. Use -I to point to the header files and -L to point to the libraries.

```bash
cc -I$HOME/install/include myprogram.c -L$HOME/install/lib -lnlopt -lm -o myprogram

```

--------------------------------

### NLopt Optimization Example in Java

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Tutorial

A complete Java example demonstrating how to define an objective function, inequality constraints, and perform optimization using the NLopt library. This implementation requires Java 1.8 or later to support lambda expressions.

```java
import nlopt.*;

public class t_java {
  private static double myfunc(double[] x, double[] grad) {
    if (grad != null) {
      grad[0] = 0.0;
      grad[1] = 0.5 / Math.sqrt(x[1]);
    }
    return Math.sqrt(x[1]);
  }

  private static double myconstraint(double[] x, double[] grad, double a,
                                     double b) {
    if (grad != null) {
      grad[0] = 3 * a * (a*x[0] + b) * (a*x[0] + b);
      grad[1] = -1.0;
    }
    return ((a*x[0] + b) * (a*x[0] + b) * (a*x[0] + b) - x[1]);
  }

  public static void main(String[] args) {
    System.loadLibrary("nloptjni");
    Opt opt = new Opt(Algorithm.LD_MMA, 2);
    opt.setLowerBounds(new DoubleVector(Double.NEGATIVE_INFINITY, 0.));
    opt.setMinObjective(t_java::myfunc);
    opt.addInequalityConstraint((x, grad) -> myconstraint(x, grad, 2, 0), 1e-8);
    opt.addInequalityConstraint((x, grad) -> myconstraint(x, grad, -1, 1),
                                1e-8);
    opt.setXtolRel(1e-4);
    DoubleVector x = opt.optimize(new DoubleVector(1.234, 5.678));
    double minf = opt.lastOptimumValue();
    System.out.println("optimum at " + x);
    System.out.println("minimum value: " + minf);
    System.out.println("result code: " + opt.lastOptimizeResult());
  }
}
```

--------------------------------

### Install MinGW cmake and build NLopt

Source: https://nlopt.readthedocs.io/en/latest/NLopt_on_Windows

Install the MinGW version of cmake using pacman, then build NLopt with the MSYS Makefiles generator to ensure cmake produces the correct makefile type.

```bash
pacman -S mingw-w64-x86_64-cmake
```

```bash
cmake -G"MSYS Makefiles" . && make
```

--------------------------------

### Set and get initial step size

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Python_Reference

Sets or gets initial step sizes for derivative-free optimization. dx can be an array (NumPy or list) or a single number for all dimensions. get_initial_step returns the step used for a starting guess x in optimize(x).

```python
opt.set_initial_step(dx)
dx = opt.get_initial_step(x)
```

--------------------------------

### Install NLopt via vcpkg

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Installation

Build and install NLopt using the vcpkg dependency manager. The NLopt port is maintained by Microsoft team members and community contributors; if the version is out of date, create an issue or pull request on the vcpkg repository.

```shell
git clone https://github.com/Microsoft/vcpkg.git
cd vcpkg
./bootstrap-vcpkg.sh
./vcpkg integrate install
./vcpkg install nlopt
```

--------------------------------

### GNU Guile (Scheme) NLopt optimization example

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Tutorial

Complete example using NLopt in GNU Guile. Defines objective and constraint functions that take x and grad arguments, sets lower bounds, adds two inequality constraints with tolerances, and runs the optimizer with NLOPT-LD-MMA. Note the side-effect style and the mapping of nlopt:: C++ functions to nlopt- Guile functions.

```Scheme
(use-modules (nlopt))
(define (myfunc x grad)
  (if grad
      (begin
        (vector-set! grad 0 0.0)
        (vector-set! grad 1 (/ 0.5 (sqrt (vector-ref x 1))))))
  (sqrt (vector-ref x 1)))
(define (myconstraint x grad a b)
  (let ((x0 (vector-ref x 0)) (x1 (vector-ref x 1)))
    (if grad
        (begin
          (vector-set! grad 0 (* 3 a (expt (+ (* a x0) b) 2)))
          (vector-set! grad 1 -1.0)))
    (- (expt (+ (* a x0) b) 3) x1)))
(define opt (new-nlopt-opt NLOPT-LD-MMA 2))
(nlopt-opt-set-lower-bounds opt (vector (- (inf)) 0))
(nlopt-opt-set-min-objective opt myfunc)
(nlopt-opt-add-inequality-constraint opt (lambda (x grad)
                                           (myconstraint x grad 2 0))
                                     1e-8)
(nlopt-opt-add-inequality-constraint opt (lambda (x grad)
                                           (myconstraint x grad -1 1))
                                     1e-8)
(nlopt-opt-set-xtol-rel opt 1e-4)
(define x (nlopt-opt-optimize opt (vector 1.234 5.678)))
(define minf (nlopt-opt-last-optimum-value opt))
(define result (nlopt-opt-last-optimize-result opt))

```

--------------------------------

### Get algorithm name

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Reference

Returns a descriptive string for a given algorithm.

```c
const char *nlopt_algorithm_name(nlopt_algorithm algorithm);
```

--------------------------------

### Expected Output for NLopt Optimization

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Tutorial

The expected console output after running the optimization example.

```text
optimum at  0.333333331366 0.296296292697
minimum value =  0.544331050646
result =  4
```

--------------------------------

### Set and get vector storage for limited-memory quasi-Newton algorithms

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Java_Reference

Sets or gets the number M of stored vectors for limited-memory quasi-Newton algorithms. The default is M=0, in which case NLopt uses a heuristic nonzero value.

```java
opt.setVectorStorage(M);
opt.getVectorStorage();
```

--------------------------------

### Perform Optimization

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Tutorial

Execute the optimization process starting from an initial guess and handle the result.

```c
double x[2] = { 1.234, 5.678 };   /* `*`some initial guess`*` */
double minf; /* `*`the minimum objective value, upon return`*` */
if (nlopt_optimize(opt, x, &minf) < 0) {
    printf("nlopt failed!\n");
}
else {
    printf("found minimum at f(%g,%g) = %0.10g\n", x[0], x[1], minf);
}
```

--------------------------------

### opt.optimize(x)

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Python_Reference

Performs the optimization starting from an initial guess and returns the optimized parameters.

```APIDOC
## opt.optimize(x)

### Description
Performs the optimization starting from an initial guess and returns the optimized parameters.

### Method
optimize

### Parameters
- **x** (array) - Required - An array (NumPy array or Python list) of length n (the dimension of the problem) giving an initial guess for the optimization parameters.

### Request Example
```python
xopt = opt.optimize(x)
```

### Response
Returns a NumPy array containing the optimized values of the optimization parameters.
```

--------------------------------

### Get algorithm name string

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Python_Reference

Returns a string description of the algorithm used by the nlopt.opt object.

```python
opt.get_algorithm_name()

```

--------------------------------

### Get algorithm name string

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Guile_Reference

Returns a string description of the algorithm used by the given nlopt-opt object.

```scheme
(nlopt-opt-get-algorithm-name opt)
```

--------------------------------

### Initialize and Run NLopt Optimization

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Tutorial

Example of setting up an optimization problem using the nlopt::opt object and handling results with exceptions.

```cpp
nlopt::opt opt(nlopt::LD_MMA, 2);
std::vector<double> lb(2);
lb[0] = -HUGE_VAL; lb[1] = 0;
opt.set_lower_bounds(lb);
opt.set_min_objective(myfunc, NULL);
my_constraint_data data[2] = { {2,0}, {-1,1} };
opt.add_inequality_constraint(myconstraint, &data[0], 1e-8);
opt.add_inequality_constraint(myconstraint, &data[1], 1e-8);
opt.set_xtol_rel(1e-4);
std::vector<double> x(2);
x[0] = 1.234; x[1] = 5.678;
double minf;

try{
    nlopt::result result = opt.optimize(x, minf);
    std::cout << "found minimum at f(" << x[0] << "," << x[1] << ") = "
        << std::setprecision(10) << minf << std::endl;
}
catch(std::exception &e) {
    std::cout << "nlopt failed: " << e.what() << std::endl;
}
```

--------------------------------

### Set and get initial step size

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Java_Reference

Sets and gets the initial step sizes for derivative-free optimization. The setter accepts a DoubleVector of nonzero steps per dimension or a single number for uniform steps. The getter returns the step that will be used for a given starting guess x in opt.optimize(x).

```java
opt.setInitialStep(dx);
DoubleVector dx = opt.getInitialStep(x);
```

--------------------------------

### Get NLopt version components

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Python_Reference

Returns the major, minor, and bugfix components of the NLopt version number at runtime. For example, version 3.1.4 would return major=3, minor=1, and bugfix=4.

```python
nlopt.version_major()
```

```python
nlopt.version_minor()
```

```python
nlopt.version_bugfix()
```

--------------------------------

### Initialize Optimization Object

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Tutorial

Set up the lower bounds and the optimization object with the chosen algorithm.

```c
double lb[2] = { -HUGE_VAL, 0 }; /* lower bounds */
nlopt_opt opt;
```

```c
opt = nlopt_create(NLOPT_LD_MMA, 2); /* algorithm and dimensionality */
nlopt_set_lower_bounds(opt, lb);
nlopt_set_min_objective(opt, myfunc, NULL);
```

--------------------------------

### Set and get forced-stop integer values

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Reference

Allows setting a custom integer value to provide information about a forced stop, which can be retrieved later. The value is reset to zero at the start of each optimization.

```c
nlopt_result nlopt_set_force_stop(nlopt_opt opt, int val)
```

```c
int nlopt_get_force_stop(nlopt_opt opt)
```

--------------------------------

### Compiling and linking an NLopt program

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Tutorial

Compile and link the tutorial.c file on Unix systems using the -lnlopt and -lm flags.

```bash
cc tutorial.c -o tutorial -lnlopt -lm
```

--------------------------------

### Get NLopt version numbers with nlopt-version-major, nlopt-version-minor, and nlopt-version-bugfix

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Guile_Reference

Returns the major, minor, and bugfix components of the NLopt version at runtime. For example, version 3.1.4 would return major=3, minor=1, and bugfix=4.

```scheme
(nlopt-version-major)
```

```scheme
(nlopt-version-minor)
```

```scheme
(nlopt-version-bugfix)
```

--------------------------------

### Initial Step Size Methods

Source: https://nlopt.readthedocs.io/en/latest/NLopt_C-plus-plus_Reference

Methods to get and set the initial step sizes for derivative-free optimization algorithms.

```APIDOC
## set_initial_step (vector)

### Description
Sets the initial step sizes for derivative-free optimization algorithms using a vector of step sizes.

### Method
set_initial_step

### Signature
void nlopt::opt::set_initial_step(const std::vector<double> &dx);

### Parameters
- **dx** (const std::vector<double>&) - Required - Vector of initial step sizes for each dimension.

## set_initial_step (scalar)

### Description
Sets the initial step size for derivative-free optimization algorithms using a single scalar value applied to all dimensions.

### Method
set_initial_step

### Signature
void nlopt::opt::set_initial_step(double dx);

### Parameters
- **dx** (double) - Required - Initial step size applied to all dimensions.

## get_initial_step

### Description
Gets the initial step sizes for derivative-free optimization algorithms.

### Method
get_initial_step

### Signature
void nlopt::opt::get_initial_step(const std::vector<double> &x, std::vector<double> &dx) const;

### Parameters
- **x** (const std::vector<double>&) - Required - The point at which to evaluate the initial step.
- **dx** (std::vector<double>&) - Output - The resulting initial step sizes.
```

--------------------------------

### Get NLopt version number at runtime

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Fortran_Reference

Returns the NLopt version number at runtime. The three integer arguments receive the major, minor, and bugfix components; for example, version 3.1.4 yields major=3, minor=1, and bugfix=4.

```fortran
call nloptv(major, minor, bugfix)

```

--------------------------------

### Set and get initial step sizes

Source: https://nlopt.readthedocs.io/en/latest/NLopt_C-plus-plus_Reference

Methods to define or retrieve initial step sizes for derivative-free optimization algorithms in C++.

```cpp
void nlopt::opt::set_initial_step(const std::vector<double> &dx);
void nlopt::opt::set_initial_step(double dx);
void nlopt::opt::get_initial_step(const std::vector<double> &x, std::vector<double> &dx) const;
```

--------------------------------

### Main Optimization Program in Fortran

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Tutorial

A complete Fortran program demonstrating how to set up and run an optimization using the NLopt interface.

```Fortran
     program main
     external myfunc, myconstraint
     double precision lb(2)
     integer*8 opt
     double precision d1(2), d2(2)
     double precision x(2), minf
     integer ires
     include 'nlopt.f'
     
     call nlo_create(opt, NLOPT_LD_MMA, 2)
     call nlo_get_lower_bounds(ires, opt, lb)
     lb(2) = 0.0
     call nlo_set_lower_bounds(ires, opt, lb)
     call nlo_set_min_objective(ires, opt, myfunc, 0)
     
     d1(1) = 2.
     d1(2) = 0.
     call nlo_add_inequality_constraint(ires, opt, 
$        myconstraint, d1, 1.D-8)
     d2(1) = -1.
     d2(2) = 1.
     call nlo_add_inequality_constraint(ires, opt,
$        myconstraint, d2, 1.D-8)
     
     call nlo_set_xtol_rel(ires, opt, 1.D-4)
     
     x(1) = 1.234
     x(2) = 5.678
     call nlo_optimize(ires, opt, x, minf)
     if (ires.lt.0) then
        write(*,*) 'nlopt failed!'
     else
        write(*,*) 'found min at ', x(1), x(2)
        write(*,*) 'min val = ', minf
     endif
     
     call nlo_destroy(opt)
     
     end
```

--------------------------------

### Set and get stochastic population

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Python_Reference

Sets or gets the initial population for stochastic algorithms. A pop of zero uses the heuristic default.

```python
opt.set_population(pop)
opt.get_population()
```

--------------------------------

### Set and get stochastic population

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Java_Reference

Sets and gets the initial population for stochastic optimization algorithms. A population of zero means the heuristic default will be used.

```java
opt.setPopulation(pop);
opt.getPopulation();
```

--------------------------------

### Get initial step sizes with nlopt_get_initial_step

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Reference

Retrieves the initial step sizes that NLopt will use. Pass the same initial guess x that will be given to nlopt_optimize, because the heuristic step size may depend on x. On successful return, dx (an array of length n) contains the initial step sizes.

```c
nlopt_result nlopt_get_initial_step(const nlopt_opt opt, const double *x, double *dx);
```

--------------------------------

### Include NLopt Headers

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Tutorial

Include the necessary NLopt and math headers for the optimization implementation.

```c
#include <math.h>
#include <nlopt.h>
```

--------------------------------

### Set and get stochastic population in Guile: nlopt-opt-set-population and nlopt-opt-get-population

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Guile_Reference

Sets or gets the initial population for stochastic optimization algorithms. A pop of zero implies the heuristic default will be used.

```guile
(nlopt-opt-set-population opt pop)
(nlopt-opt-get-population opt)
```

--------------------------------

### Set and get stochastic population size

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Deprecated_API_Reference

Sets and gets the global population parameter for stochastic algorithms. The default is zero, which is interpreted as letting the algorithm choose an algorithm-specific default value.

```c
void nlopt_set_stochastic_population(int pop);
int nlopt_get_stochastic_population(void);
```

--------------------------------

### Set initial step sizes with nlopt_set_initial_step

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Reference

Sets the initial step size for derivative-free local optimization. dx is an array of length n (the problem dimension) containing nonzero initial step sizes for each component of x. Passing NULL for dx makes NLopt use its heuristics to determine the step size.

```c
nlopt_result nlopt_set_initial_step(nlopt_opt opt, const double* dx);
```

--------------------------------

### Set and get vector storage with nlopt-opt-set-vector-storage and nlopt-opt-get-vector-storage

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Guile_Reference

Sets or gets the number M of stored vectors for limited-memory quasi-Newton algorithms. The default is M=0, in which case NLopt uses a heuristic nonzero value.

```scheme
(nlopt-opt-set-vector-storage opt M)
```

```scheme
(nlopt-opt-get-vector-storage opt)
```

--------------------------------

### Link NLopt library on Unix

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Reference

Example command for linking the NLopt library and the math library during compilation on Unix systems. The -lnlopt and -lm flags must follow the source or object files.

```bash
compiler ...source/object files... -lnlopt -lm -o myprogram
```

--------------------------------

### Set Octave plugin install directories with -DINSTALL_OCT_DIR and -DINSTALL_M_DIR

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Installation

Override the default installation directories for Octave plugins (.oct files) and .m script files. The defaults are typically /usr/local/lib/octave/2.1.73/site/oct/i486-pc-linux-gnu and /usr/local/share/octave/2.1.73/site/m/ respectively.

```cmake
cmake -DINSTALL_OCT_DIR=octdir -DINSTALL_M_DIR=mdir ..
```

--------------------------------

### Set Matlab plugin install directory with -DINSTALL_MEX_DIR

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Installation

Override the default installation directory for Matlab plugins (INSTALL_MEX_DIR). When using a custom directory, you must run Matlab from that directory or add it to the Matlab path.

```cmake
cmake -DINSTALL_MEX_DIR=dir ..
```

--------------------------------

### Build NLopt with CMake

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Installation

Build NLopt from source using CMake. Run these commands in the nlopt directory. Requires a C compiler and optionally Octave, Matlab, Guile, or Python for plugins.

```bash
mkdir build
cd build
cmake ..
make

```

--------------------------------

### Set and get initial step sizes in Fortran (nlo_set_initial_step, nlo_set_initial_step1, nlo_get_initial_step)

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Fortran_Reference

Sets or retrieves the initial step sizes for derivative-free optimization. `dx` is an array of nonzero initial steps per dimension; `dx1` is a single value applied to all dimensions. `ires` is an integer return value (positive on success).

```Fortran
double precision x(n) dx(n), dx1
call nlo_set_initial_step(ires, opt, dx)
call nlo_set_initial_step1(ires, opt, dx1)
call nlo_get_initial_step(ires, opt, x, dx)

```

--------------------------------

### Set and get vector storage for limited-memory quasi-Newton algorithms

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Python_Reference

Sets or gets the number M of stored vectors for limited-memory quasi-Newton algorithms. The default is M=0, in which case NLopt uses a heuristic nonzero value.

```python
opt.set_vector_storage(M)
```

```python
opt.get_vector_storage()
```

--------------------------------

### Set uniform initial step with nlopt_set_initial_step1

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Reference

Convenience variant of nlopt_set_initial_step that sets the same step size dx in every direction. Use when all components of the initial step should be equal.

```c
nlopt_result nlopt_set_initial_step1(nlopt_opt opt, double dx);
```

--------------------------------

### Configure Optimization Structure

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Tutorial

Setting up the opt structure with algorithm, bounds, objective, and constraints.

```matlab
opt.algorithm = NLOPT_LD_MMA
opt.lower_bounds = [-inf, 0]
opt.min_objective = @myfunc
opt.fc = { (@(x) myconstraint(x,2,0)), (@(x) myconstraint(x,-1,1)) }
opt.fc_tol = [1e-8, 1e-8];
opt.xtol_rel = 1e-4
```

--------------------------------

### Get number of evaluations

Source: https://nlopt.readthedocs.io/en/latest/NLopt_C-plus-plus_Reference

Request the number of evaluations.

```cpp
int nlopt::opt::get_numevals() const;
```

--------------------------------

### setInitialStep and getInitialStep

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Java_Reference

These methods set and retrieve the initial step sizes for derivative-free optimization algorithms. The setter accepts a DoubleVector of nonzero initial steps per dimension or a single number for uniform steps, while the getter returns the initial step that will be used for a given starting guess.

```APIDOC
## setInitialStep

### Description
Sets the initial step sizes for derivative-free optimization algorithms.

### Method
`void setInitialStep(DoubleVector dx)`

### Parameters
- **dx** (DoubleVector) - Required - A DoubleVector of nonzero initial steps for each dimension, or a single number to use the same initial step for all dimensions.

### Example
```java
opt.setInitialStep(dx);
```

## getInitialStep

### Description
Returns the initial step that will be used for a given starting guess x in opt.optimize(x).

### Method
`DoubleVector getInitialStep(DoubleVector x)`

### Parameters
- **x** (DoubleVector) - Required - The starting guess for which the initial step is to be retrieved.

### Returns
- **DoubleVector** - The initial step sizes that will be used for the given starting guess.

### Example
```java
DoubleVector dx = opt.getInitialStep(x);
```
```

--------------------------------

### Get numevals

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Fortran_Reference

Requests the number of evaluations (nevals).

```fortran
call nlo_get_numevals(nevals, opt)

```

--------------------------------

### Run optimization with opt.optimize(x)

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Python_Reference

Call this to perform the optimization. On input, x is an array (NumPy array or Python list) of length n (the dimension from the nlopt.opt constructor) giving an initial guess. The return value xopt is a NumPy array containing the optimized values.

```python
xopt = opt.optimize(x)

```

--------------------------------

### setXtolRel / getXtolRel

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Java_Reference

Set or get the relative tolerance on the optimization parameters.

```APIDOC
## setXtolRel / getXtolRel

### Description
Set or get the relative tolerance on the optimization parameters.

### Methods
- `opt.setXtolRel(tol)` - Set the relative tolerance.
- `opt.getXtolRel()` - Get the current relative tolerance.

### Parameters
- `tol` (double) - Required - The relative tolerance value.

### Example
```java
opt.setXtolRel(tol);
double currentXtolRel = opt.getXtolRel();
```
```

--------------------------------

### setFtolAbs / getFtolAbs

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Java_Reference

Set or get the absolute tolerance on the function value.

```APIDOC
## setFtolAbs / getFtolAbs

### Description
Set or get the absolute tolerance on the function value.

### Methods
- `opt.setFtolAbs(tol)` - Set the absolute tolerance.
- `opt.getFtolAbs()` - Get the current absolute tolerance.

### Parameters
- `tol` (double) - Required - The absolute tolerance value.

### Example
```java
opt.setFtolAbs(tol);
double currentFtolAbs = opt.getFtolAbs();
```
```

--------------------------------

### Execute optimization with nlopt_optimize

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Reference

Performs the optimization process. On input, x is the initial guess; on success, x is updated with optimized values and opt_f contains the objective function result.

```c
nlopt_result nlopt_optimize(nlopt_opt opt, double *x, double *opt_f);
```

--------------------------------

### setFtolRel / getFtolRel

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Java_Reference

Set or get the relative tolerance on the function value.

```APIDOC
## setFtolRel / getFtolRel

### Description
Set or get the relative tolerance on the function value.

### Methods
- `opt.setFtolRel(tol)` - Set the relative tolerance.
- `opt.getFtolRel()` - Get the current relative tolerance.

### Parameters
- `tol` (double) - Required - The relative tolerance value.

### Example
```java
opt.setFtolRel(tol);
double currentFtolRel = opt.getFtolRel();
```
```

--------------------------------

### Build NLopt as a static library with -DBUILD_SHARED_LIBS=OFF

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Installation

Compile NLopt as a static library instead of the default shared library. Add this flag to the cmake command, then run make and make install as usual.

```cmake
cmake -DBUILD_SHARED_LIBS=OFF ..
```

--------------------------------

### MMA algorithm verbose output

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Tutorial

Example output showing objective function values at each intermediate step for the MMA algorithm.

```text
nlopt_minimize_constrained eval #1: 2.38286
nlopt_minimize_constrained eval #2: 2.35613
nlopt_minimize_constrained eval #3: 2.24586
nlopt_minimize_constrained eval #4: 2.0191
nlopt_minimize_constrained eval #5: 1.74093
nlopt_minimize_constrained eval #6: 1.40421
nlopt_minimize_constrained eval #7: 1.0223
nlopt_minimize_constrained eval #8: 0.685203
nlopt_minimize_constrained eval #9: 0.552985
nlopt_minimize_constrained eval #10: 0.544354
nlopt_minimize_constrained eval #11: 0.544331
```

--------------------------------

### Get number of evaluations (nevals) in Guile

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Guile_Reference

Request the number of evaluations.

```scheme
(nlopt-opt-get-nevals opt)
```

--------------------------------

### Get number of evaluations

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Python_Reference

Requests the number of evaluations performed so far.

```python
opt.get_numevals()

```

--------------------------------

### Enable Matlab plugin with -DNLOPT_MATLAB=ON and set Matlab_ROOT_DIR

Source: https://nlopt.readthedocs.io/en/latest/NLopt_Installation

Enable the Matlab plugin build and specify the Matlab installation directory. Some Matlab versions also require compiling NLopt as a shared library. Use -DNLOPT_MATLAB=OFF to disable the plugin.

```cmake
cmake -DNLOPT_MATLAB=ON -DMatlab_ROOT_DIR=/opt/matlab/RYYYYx/ ..
```
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