CAMLprim value ml_gsl_sf_gegenpoly_array(value lambda, value x, value r_arr)
{
gsl_sf_gegenpoly_array(Double_array_length(r_arr)-1,
Double_val(lambda),
Double_val(x),
Double_array_val(r_arr));
return Val_unit;
}
//Calculates the Gegenbauer polynomials
void compute_C(double xi, int N, int L, double * C_array)
{
int l;
for (l = 0; l < L; l++)
{
gsl_sf_gegenpoly_array(N - 1, 3./2 + 2*l, xi, C_array + l*N);
}
}
static VALUE rb_gsl_sf_gegenpoly_array(VALUE obj, VALUE nmax, VALUE lambda, VALUE x)
{
gsl_vector *v = NULL;
CHECK_FIXNUM(nmax);
Need_Float(lambda); Need_Float(x);
v = gsl_vector_alloc(nmax);
gsl_sf_gegenpoly_array(FIX2INT(nmax), NUM2DBL(lambda), NUM2DBL(x), v->data);
return Data_Wrap_Struct(cgsl_vector, 0, gsl_vector_free, v);
}
//Calculates the derivative of the Gegenbauer polynomials
void compute_dC(double xi, int N, int L, double * dC_array)
{
int n,l;
for (l = 0; l < L; l++)
{
*(dC_array +l*N) = 0;
if (N != 1)
gsl_sf_gegenpoly_array(N - 2, 5./2 + 2*l, xi, dC_array + l*N + 1);
for (n = 0; n<N; n++)
{
*(dC_array +l*N + n) *= 2*(2*l + 3./2);
}
}
}
//Calculates the second derivative of the Gegenbauer polynomials
void compute_d2C(double xi, int N, int L, double * d2C_array)
{
int n,l;
for (l = 0; l < L; l++)
{
*(d2C_array +l*N) = 0;
if (N >1)
*(d2C_array +l*N + 1) = 0;
if (N > 2)
gsl_sf_gegenpoly_array(N - 3, 7./2 + 2*l, xi, d2C_array + l*N + 2);
for (n = 0; n<N; n++)
{
*(d2C_array +l*N + n) *= 4*(2*l + 3./2)*(2*l + 5./2);
}
}
}
