Bessel transforms

To compute Bessel transforms of a real function $f$ we need first its Fourier transform :

def_four tr f 1024

for example. We define also a new kind of object which contains some parameters to compute the last two formulas of 4.2.1 (i.e. some values of the $\sin\theta$ and $\cos(n\theta)$ or $\sin(n\theta)$). This is done with the instruction

def_bes_par xx n n2

Here xx is the name of the object that will contain the parameters, n is the number of the Bessel transform and n2 the number of points in the interval $[0,\frac{2}{\pi}]$ used to compute the integrals. The same object can be used to compute the n-th Bessel tranform of other functions. To compute the Bessel transform of order n of $f$ we use the instruction

trans_bessel tr xx g

where g is a real function that will contain the result.