Pure quadrature

Arguments

Description

During integration, the solver can compute simultaneously quadratures/integrals of a function g depending on time t and solution when solving an ODE or a DAE:

These quantities could be added as new states and trivial equations in the original problem since but giving them separately avoids computing useless Jacobians and saves the solver effort. The value of g is given by the output of fun, which has the same prototype as a classical ODE rhs or DAE residual. After the solver call the quadrature variables are retrieved in the "q" field of either the info or sol output argument, as in the following examples (typically, only the final value of q will be of interest). The initial values of the quadrature variables are zero by default but can be set with the option yQ0. Note

Examples

function dyqdt=g(t, y)
    dyqdt = t*y(1);
end
[t,y,info] = cvode(%SUN_vdp1, [0 1], [1 2], quadRhs=g);
info.q

function dyqdt=g(t, y, yp)
    dyqdt = y(2);
end
y0  = [1-1e-6; 1e-6; 0];
yp0 = [-2e-7; 1.5e-7; 5e-8];
[t,y,info] = ida(%SUN_sir, [0,200], y0, yp0, quadRhs=g);
info.q

Options

See also

• arkode — SUNDIALS ordinary differential equation additive Runge-Kutta solver
• cvode — SUNDIALS ordinary differential equation solver
• ida — SUNDIALS differential-algebraic equation solver
• User functions — Coding user functions used by SUNDIALS solvers
• Options (ODE and DAE solvers) — Changing the default behavior of solver
• SUN_Clink — Compiling and linking a C user function