Re: Difficulty using boost quadrature library

From: Anirban Pal (anirban.pal.iitkgp_at_[hidden])
Date: 2020-08-14 14:48:42

Thank you. That worked.

On Fri, 14 Aug 2020 at 05:23, John Maddock via Boost-users <
boost-users_at_[hidden]> wrote:

>
> On 14/08/2020 01:07, Anirban Pal via Boost-users wrote:
> > Hello everyone,
> >
> > I'm new to using boost and I'm trying to use its quadrature routines,
> > specifically
> > the *tanh_sinh* integrator. I'm trying to run the examples here:
> >
> > <goog_14736225>
> >
> https://www.boost.org/doc/libs/1_66_0/libs/math/doc/html/math_toolkit/double_exponential/de_tanh_sinh.html
> > <
> https://www.boost.org/doc/libs/1_66_0/libs/math/doc/html/math_toolkit/double_exponential/de_tanh_sinh.html
> >
> >
> > I've been successful using it with the *double* datatype. However, I
> > can't seem to work with the *Real* datatype. When I run the following,
> > I'm successful.
> > tanh_sinh<double>  integrator;
> > auto  f  =  [](double  x)  {  return  5*x  +  7;  };
> > double  Q  =  integrator.integrate(f);
> > Q  =  integrator.integrate(f,  0.0,  1.1);
> >
> > But when I run the following:
> > auto  f  =  [](Real  x)  {  return  log(x)*log(1-x);  };
> > Real  Q  =  integrator.integrate(f,  (Real)  0,  (Real)  1);
>
> I confess that's not the best example in the docs :(
>
> The name "Real" is just used as "some kind of floating point type" -
> replace with whatever actual type you wish to use.
>
> > I get the error:
> >
> > boost_test.cxx: In function ‘int main(int, char**)’:
> > boost_test.cxx:47:15: error: ‘Real’ has not been declared
> >   auto f2 = [](Real x) { return log(x)*log(1-x); };
> >                ^~~~
> > boost_test.cxx:48:2: error: ‘Real’ was not declared in this scope
> >   Real Q2 = integrator.integrate(f2, (Real) 0, (Real) 1);
> >
> > I think I need to include the right headers for this to go away.
> > However, I'm not sure what the correct header file is.
> >
> > Thank you for your attention.
> >
> > --
> > Anirban Pal
> >
> >
> >
> >
> > _______________________________________________
> > Boost-users mailing list
> > Boost-users_at_[hidden]
> > https://lists.boost.org/mailman/listinfo.cgi/boost-users
>
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-- 
Anirban Pal