---
name: "Math::GSL::Chebyshev"
section: "3pm"
platform: "linux"
package: "libmath-gsl-perl"
version: "0.45-2+b1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Math::GSL::Chebyshev"
---

# Math::GSL::Chebyshev(3pm)

Univariate Chebyshev Series Approximation

## NAME

Math::GSL::Chebyshev - Univariate Chebyshev Series Approximation

## SYNOPSIS

```
    use Math::GSL::Chebyshev qw/:all/;
    my $cheb             = gsl_cheb_alloc(40);
    my $function         = sub { sin(cos($_[0])) };
    gsl_cheb_init($cheb, $function, 0, 10);
    my $x                = gsl_cheb_eval($cheb, 5.5 );
    my ($status,$y,$err) = gsl_cheb_eval_err($cheb, 7.5 );
    gsl_cheb_free($cheb);
```

## DESCRIPTION

- •

  `gsl_cheb_alloc($size)`

  ```
      my $cheb = gsl_cheb_alloc(50);
  ```

  Allocates a new Chebyshev object with `$size` sample points.

- •

  `gsl_cheb_free($cheb)`

  Deallocates memory associated to `$cheb`. Returns void.

- •

  `"gsl_cheb_init($cheb,$function, $lower, $upper)"`

  ```
      gsl_cheb_init($cheb, sub { sin(cos($_[0])) }, 0, 10 );
  ```

  Initiate a Chebyshev object with a function and upper and lower bounds. Returns void.

- •

  `"gsl_cheb_eval($function, $value)"`

  ```
      my $evaluated = gsl_cheb_eval($cheb, 5 );
  ```

  Returns a Perl scalar of the Chebyshev object `$cheb` evaluated at `$value`.

- •

  `"gsl_cheb_eval_err($cheb, $value)"`

  ```
      my ($status,$evaluated,$err) = gsl_cheb_eval($cheb, 5 );
  ```

  Returns a list consisting of a GSL status code, the evaluate value and the estimated error of the evaluation.

- •

  `"gsl_cheb_eval_n "`

- •

  `"gsl_cheb_eval_n_err "`

- •

  `"gsl_cheb_eval_mode "`

- •

  `"gsl_cheb_eval_mode_e "`

- •

  `"gsl_cheb_calc_deriv($deriv,$cheb) "`

  ```
     my $status = gsl_cheb_calc_deriv( $deriv, $cheb );
  ```

  This will calculate the derivative of `$cheb` and stores it in `$deriv`, which must be pre-allocated. Returns a GSL status code.

- •

  `"gsl_cheb_calc_integ($integ,$cheb) "`

  ```
     my $status = gsl_cheb_calc_integ( $deriv, $cheb );
  ```

  This will calculate the derivative of `$cheb` and stores it in `$deriv`, which must be pre-allocated. Returns a GSL status code.

For more information on the functions, we refer you to the GSL official documentation: \<http://www.gnu.org/software/gsl/manual/html\_node/\>

## AUTHORS

Jonathan "Duke" Leto \<jonathan@leto.net\> and Thierry Moisan \<thierry.moisan@gmail.com\>

## COPYRIGHT AND LICENSE

Copyright (C) 2008-2024 Jonathan "Duke" Leto and Thierry Moisan

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.