Rheolef  7.2
an efficient C++ finite element environment
 
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neumann-laplace-lambda.cc
Go to the documentation of this file.
1
25#include "rheolef.h"
26using namespace rheolef;
27using namespace std;
28size_t d;
29Float f (const point& x) { return 1; }
30Float g (const point& x) { return -0.5/d; }
31int main(int argc, char**argv) {
32 environment rheolef (argc, argv);
33 geo omega (argv[1]);
34 d = omega.dimension();
35 space Xh (omega, argv[2]);
36 trial u (Xh); test v (Xh);
37 form a = integrate (dot(grad(u),grad(v)));
38 field b = integrate(v);
39 field lh = integrate (f*v) + integrate ("boundary", g*v);
40 form A = {{ a, b},
41 { trans(b), 0}};
42 field B = { lh, 0};
43 A.set_symmetry(true);
44 space IR = space::real();
45 space Yh = Xh*IR;
46 field Uh (Yh,0);
47 problem p (A);
48 p.solve (B, Uh);
49 dout << catchmark("u") << Uh[0];
50 // get lambda:
51 Float lambda = (Uh.comm().rank() == Uh.constraint_process_rank()) ? Uh[1].dof(0) : 0;
52#ifdef _RHEOLEF_HAVE_MPI
53 mpi::broadcast (Uh.comm(), lambda, Uh.constraint_process_rank());
54#endif // _RHEOLEF_HAVE_MPI
55 dout << catchmark("lambda") << lambda << endl;
56 check_macro(fabs(lambda) < 1e-10, "unexpected lambda="<<lambda);
57}
field lh(Float epsilon, Float t, const test &v)
see the Float page for the full documentation
see the field page for the full documentation
see the form page for the full documentation
see the geo page for the full documentation
see the point page for the full documentation
see the problem page for the full documentation
see the catchmark page for the full documentation
Definition catchmark.h:67
see the environment page for the full documentation
see the space page for the full documentation
see the test page for the full documentation
see the test page for the full documentation
int main()
Definition field2bb.cc:58
check_macro(expr1.have_homogeneous_space(Xh1), "dual(expr1,expr2); expr1 should have homogeneous space. HINT: use dual(interpolate(Xh, expr1),expr2)")
This file is part of Rheolef.
std::enable_if< details::has_field_rdof_interface< Expr >::value, details::field_expr_v2_nonlinear_terminal_field< typenameExpr::scalar_type, typenameExpr::memory_type, details::differentiate_option::gradient > >::type grad(const Expr &expr)
grad(uh): see the expression page for the full documentation
std::enable_if< details::is_field_expr_v2_nonlinear_arg< Expr >::value &&!is_undeterminated< Result >::value, Result >::type integrate(const geo_basic< T, M > &omega, const Expr &expr, const integrate_option &iopt, Result dummy=Result())
see the integrate page for the full documentation
Definition integrate.h:211
rheolef::std enable_if ::type dot const Expr1 expr1, const Expr2 expr2 dot(const Expr1 &expr1, const Expr2 &expr2)
csr< T, sequential > trans(const csr< T, sequential > &a)
trans(a): see the form page for the full documentation
Definition csr.h:455
STL namespace.
rheolef - reference manual
Definition cavity_dg.h:29
Definition cavity_dg.h:25
Definition sphere.icc:25
Definition leveque.h:25