Rheolef  7.2
an efficient C++ finite element environment
 
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gauss_jacobi.icc
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1
21#include "rheolef/compiler.h"
22#include "rheolef/gamma.h"
23#include "rheolef/jacobi.h"
24#include "rheolef/jacobi_roots.h"
25#include <iterator>
26namespace rheolef {
27template <class Size, class OutputIterator1, class OutputIterator2>
28void
29gauss_jacobi (Size R,
30 typename std::iterator_traits<OutputIterator1>::value_type alpha,
31 typename std::iterator_traits<OutputIterator1>::value_type beta,
32 OutputIterator1 zeta, OutputIterator2 omega)
33{
34 typedef typename std::iterator_traits<OutputIterator1>::value_type T;
35 T num = pow(T(2.), alpha+beta+3)/sqr(alpha+beta+T(1.*R)+1);
36 if (alpha == floor(alpha) && beta == floor(beta))
37 for (Size k = 1; k <= size_t(static_cast<int>(beta)); k++)
38 num *= (T(1.*R)+T(1.*k))/(alpha+T(1.*R)+T(1.*k));
39 else
40 num *= (my_gamma(alpha+T(1.*R)+1)/my_gamma(alpha+beta+T(1.*R)+1))
41 *(my_gamma(beta+T(1.*R)+1)/my_gamma(T(1.*R)+1));
42 jacobi_roots (R, alpha, beta, zeta);
43 jacobi<T> P (R-1, alpha+1, beta+1);
44 for (Size r = 0; r < R; r++)
45 omega[r] = num/((1-sqr(zeta[r]))*sqr(P(zeta[r])));
46}
47} // namespace rheolef
Expr1::float_type T
Definition field_expr.h:230
This file is part of Rheolef.
space_mult_list< T, M > pow(const space_basic< T, M > &X, size_t n)
Definition space_mult.h:120
void jacobi_roots(Size R, T alpha, T beta, OutputIterator zeta)
void gauss_jacobi(Size R, typename std::iterator_traits< OutputIterator1 >::value_type alpha, typename std::iterator_traits< OutputIterator1 >::value_type beta, OutputIterator1 zeta, OutputIterator2 omega)
T my_gamma(const T &x)
Definition gamma.icc:25