Hi David, Thanks for your clear answer! Yes the link is good enough. Warm regards, Serdan ________________________________ From: Ham, David A <david.ham@imperial.ac.uk> Sent: 06 August 2019 11:28:04 To: Shaerdan Shataer <ss2571@bath.ac.uk>; firedrake <firedrake@imperial.ac.uk> Subject: Re: [firedrake] question about surface integral Hi Serdan, All integrals in Firedrake are evaluated with quadrature. By default, UFL estimates the degree of quadrature required, but you can force the quadrature degree by passing it to the measure. E.g. `ds(degree=4)`. If you want to understand the design philosophy of Firedrake, the place to go is Rathgeber (2016). https://doi.org/10.1145/2998441 . Is that what you mean by “theory guide”? Regards, David From: <firedrake-bounces@imperial.ac.uk> on behalf of Shaerdan Shataer <ss2571@bath.ac.uk> Date: Tuesday, 6 August 2019 at 11:24 To: firedrake <firedrake@imperial.ac.uk> Subject: [firedrake] question about surface integral Dear all, Does anyone know how does firedrake evaluate surface integrals? Is it Gaussian quadrature? Can I find the detail somewhere? p.s. can I find a theory guide about firedrake anywhere? Many thanks, Kind regards, Serdan