# HERMITE_PRODUCT_DISPLAY Display 2D Cartesian Products of Hermite Polynomials

HERMITE_PRODUCT_DISPLAY, a MATLAB program which displays an image of a function created by the Cartesian product of two Hermite polynomials, such as f(x,y) = h(3,x) * h(1,y).

There are five types of Hermite polynomial available. Perhaps the best behaved are "Hen(n,x)" and "Hf(n,x)", which don't blow up within the plotting interval as fast as the other functions do.

The physicist's Hermite polynomial H(n,x) can be defined by:

H(n,x) = (-1)^n exp(x^2/2) * d^n/dx^n ( exp(-x^2/2) )

The normalized physicist's Hermite polynomial Hn(n,x) is scaled so that

Integral ( -oo < X < +oo ) exp ( - X^2 ) * Hn(M,X) Hn(N,X) dX = delta ( N, M )

The probabilist's Hermite polynomial He(n,x) is related to H(n,x) by:

He(n,x) = H(n,x/sqrt(2)) / sqrt ( 2^n )

The normalized probabilist's Hermite polynomial Hen(n,x) is scaled so that

Integral ( -oo < X < +oo ) exp ( - 0.5*X^2 ) * Hen(M,X) Hen(N,X) dX = delta ( N, M )

The Hermite function Hf(n,x) is related to H(n,x) by:

Hf(n,x) = H(n,x) * exp(-x^2/2) / sqrt ( 2^n * n! * sqrt ( pi ) )

and is scaled so that:
Integral ( -oo < X < +oo ) Hf(M,X) Hf(N,X) dX = delta ( N, M )

### Usage:

hermite_product_display ( 'name', i, j )
where
• 'name' is 'h', 'hn', 'he', 'hen', or 'hf';
• i is the index of the polynomial in the X direction;
• j is the index of the polynomial in the Y direction.

### Languages:

HERMITE_PRODUCT_DISPLAY is available in a MATLAB version.

### Related Data and Programs:

FEM_BASIS_Q4_DISPLAY, a MATLAB program which displays a basis function associated with a linear quadrilateral ("Q4") mesh.

FEM_BASIS_T3_DISPLAY, a MATLAB program which displays a basis function associated with a 3-node triangle "T3" mesh.

FEM_BASIS_T4_DISPLAY, a MATLAB program which displays a basis function associated with a 4-node triangle "T4" mesh.

FEM_BASIS_T6_DISPLAY, a MATLAB program which displays a basis function associated with a 6-node triangle "T6" mesh.

HERMITE_POLYNOMIAL, a MATLAB library which evaluates the physicist's Hermite polynomial, the probabilist's Hermite polynomial, the Hermite function, and related functions.

hermite_product_display, a MATLAB program which displays an image of a function created by the Cartesian product of two Hermite polynomials, such as f(x,y) = h(3,x) * h(1,y).

HERMITE_PRODUCT_POLYNOMIAL, a MATLAB library which defines Hermite product polynomials, creating a multivariate polynomial as the product of univariate Hermite polynomials.

POLYGONAL_SURFACE_DISPLAY, a MATLAB program which displays a surface in 3D described as a set of polygons;

### Examples and Tests:

Here we plot all the possible products of orders 0 through 5, using the "hen" polynomial: