std::hermite, std::hermitef, std::hermitel

C++

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Concepts library (C++20)

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Technical Specifications

Technical specifications

Filesystem library (filesystem TS)

Library fundamentals (library fundamentals TS)

Library fundamentals 2 (library fundamentals 2 TS)

Extensions for parallelism (parallelism TS)

Extensions for parallelism 2 (parallelism TS v2)

Extensions for concurrency (concurrency TS)

Concepts (concepts TS)

Ranges (ranges TS)

Special mathematical functions (special math TR)

Mathematical special functions

assoc_laguerreassoc_laguerrefassoc_laguerrel assoc_legendreassoc_legendrefassoc_legendrel betabetafbetal comp_ellint_1comp_ellint_1fcomp_ellint_1l comp_ellint_2comp_ellint_2fcomp_ellint_2l comp_ellint_3comp_ellint_3fcomp_ellint_3l cyl_bessel_icyl_bessel_ifcyl_bessel_il

cyl_bessel_jcyl_bessel_jfcyl_bessel_jl cyl_bessel_kcyl_bessel_kfcyl_bessel_kl cyl_neumanncyl_neumannfcyl_neumannl ellint_1ellint_1fellint_1l ellint_2ellint_2fellint_2l ellint_3ellint_3fellint_3l expintexpintfexpintl

hermitehermitefhermitel laguerrelaguerreflaguerrel legendrelegendreflegendrel riemann_zetariemann_zetafriemann_zetal sph_besselsph_besselfsph_bessell sph_legendresph_legendrefsph_legendrel sph_neumannsph_neumannfsph_neumannl

double hermite( unsigned int n, double x ); double hermite( unsigned int n, float x ); double hermite( unsigned int n, long double x ); float hermitef( unsigned int n, float x ); long double hermitel( unsigned int n, long double x );	(1)
double hermite( unsigned int n, IntegralType x );	(2)

1) Computes the (physicist's) Hermite polynomials of the degree n and argument x

4) A set of overloads or a function template accepting an argument of any integral type. Equivalent to (1) after casting the argument to double.

As all special functions, hermite is only guaranteed to be available in <cmath> if __STDCPP_MATH_SPEC_FUNCS__ is defined by the implementation to a value at least 201003L and if the user defines __STDCPP_WANT_MATH_SPEC_FUNCS__ before including any standard library headers.

Parameters

n	-	the degree of the polynomial
x	-	the argument, a value of a floating-point or integral type

Return value

If no errors occur, value of the order-nHermite polynomial of x, that is (-1)n
e^x2

dn

dxn

e^-x2
, is returned.

Error handling

Errors may be reported as specified in math_errhandling

• If the argument is NaN, NaN is returned and domain error is not reported
• If n is greater or equal than 128, the behavior is implementation-defined

Notes

Implementations that do not support TR 29124 but support TR 19768, provide this function in the header tr1/cmath and namespace std::tr1

An implementation of this function is also available in boost.math

The Hermite polynomials are the polynomial solutions of the equation u,,
-2xu,
= -2nu

The first few are:

• hermite(0, x) = 1
• hermite(1, x) = 2x
• hermite(2, x) = 4x2
  -2
• hermite(3, x) = 8x3
  -12x
• hermite(4, x) = 16x4
  -48x2
  +12

Example

(works as shown with gcc 6.0)

Run this code

#define __STDCPP_WANT_MATH_SPEC_FUNCS__ 1
#include <cmath>
#include <iostream>
double H3(double x) { return 8*std::pow(x,3) - 12*x; }
double H4(double x) { return 16*std::pow(x,4)-48*x*x+12; }
int main()
{
    // spot-checks
    std::cout << std::hermite(3, 10) << '=' << H3(10) << '\n'
              << std::hermite(4, 10) << '=' << H4(10) << '\n';
}

Output:

7880=7880
155212=155212

See also

laguerrelaguerreflaguerrel	Laguerre polynomials (function)
legendrelegendreflegendrel	Legendre polynomials (function)

External links

Weisstein, Eric W. ""Hermite Polynomial." From MathWorld--A Wolfram Web Resource.