On 14/08/2020 22:56, Anirban Pal via Boost-users wrote:
Hello,
I'm trying to integrate functions with BOOST quadrature routines. So
far they have been extremely impressive accuracy-wise, particularly
with multiprecision features.
I wish to integrate a function and pass some arguments to it. These
arguments can be scalars, matrices, structs or objects. I was
wondering if there is an example that explores this. Would I need to
use a boost.function? Or would a function pointer work?
To create a reusable single-valued functor that integrates from [a, x]
for fixed a, then I think some nested lambda expressions would work:
auto integral = [](double x)
{ // Integrates from 0 to x:
static tanh_sinh<double> integrator;
static auto f = [](double x) { return 5 * x + 7; };
return integrator.integrate(f, 0.0, x);
};
std::cout << integral(2) << std::endl;
std::cout << integral(4.5) << std::endl;
I'm not sure what you had in mind with non-scalar arguments, but if you
need to evaluate the above at multiple x values [x_1, x_2.... x_n] then
conceivably you could integrate from
[a, x_0]
[x_1, x_2]
....
[x_n-1, x_n]
and then sum to get the integrals
[a, x_0]
[a, x_1]
....
[a, x_n]
Which may or may not be more efficient.
HTH, John.
I currently have an implementation using GSL_functions which
explicitly allow the function and parameters to be passed as pointers.
I am curious if I can do something similar with boost.
Thank you.
--
Anirban Pal
_______________________________________________
Boost-users mailing list
Boost-users@lists.boost.org
https://lists.boost.org/mailman/listinfo.cgi/boost-users
--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
_______________________________________________
Boost-users mailing list
Boost-users@lists.boost.org
https://lists.boost.org/mailman/listinfo.cgi/boost-users
