GNU Scientific Library – Reference Manual: Initializing the Minimizer

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### 34.3 Initializing the Minimizer

Function: gsl_min_fminimizer * gsl_min_fminimizer_alloc (const gsl_min_fminimizer_type * T)

  This function returns a pointer to a newly allocated instance of a minimizer of type T. For example, the following code creates an instance of a golden section minimizer,

      const gsl_min_fminimizer_type * T
        = gsl_min_fminimizer_goldensection;
      gsl_min_fminimizer * s
        = gsl_min_fminimizer_alloc (T);

  If there is insufficient memory to create the minimizer then the function returns a null pointer and the error handler is invoked with an error code of `GSL_ENOMEM`.

Function: int gsl_min_fminimizer_set (gsl_min_fminimizer * s, gsl_function * f, double x_minimum, double x_lower, double x_upper)

  This function sets, or resets, an existing minimizer s to use the function f and the initial search interval [x_lower, x_upper], with a guess for the location of the minimum x_minimum.

  If the interval given does not contain a minimum, then the function returns an error code of `GSL_EINVAL`.

Function: int gsl_min_fminimizer_set_with_values (gsl_min_fminimizer * s, gsl_function * f, double x_minimum, double f_minimum, double x_lower, double f_lower, double x_upper, double f_upper)

  This function is equivalent to `gsl_min_fminimizer_set` but uses the values f_minimum, f_lower and f_upper instead of computing `f(x_minimum)`, `f(x_lower)` and `f(x_upper)`.

Function: void gsl_min_fminimizer_free (gsl_min_fminimizer * s)

  This function frees all the memory associated with the minimizer s.

Function: const char * gsl_min_fminimizer_name (const gsl_min_fminimizer * s)

  This function returns a pointer to the name of the minimizer. For example,

      printf ("s is a '%s' minimizer\n",
              gsl_min_fminimizer_name (s));

  would print something like `s is a 'brent' minimizer`.