options = nelson.ode.options.IDAS()
options = nelson.ode.options.IDAS(name, value)
nelson.ode.options.IDAS creates an options object for the 'idas' solver value used by the ode object workflow.
| Option group | Names | Purpose |
|---|---|---|
| Steps and tolerances | InitialStep, MaxStep, MinStep, RelTol, AbsTol, MaxOrder | Control adaptive BDF integration for residual equations. |
| Consistent initials | ComputeConsistentInitialConditions | Request consistent y0 and yp0 for fully implicit problems. |
| Linear algebra | LinearSolver, Preconditioner, Jacobian, JPattern | Supply residual-system structure and preconditioning hints. |
| Availability | 'idas' | Uses the optional fully implicit backend when it is compiled and enabled. |
This solver value is available only when Nelson is built with the optional SUNDIALS backend. It uses IDAS with the BDF method for fully implicit residual problems F(t,y,yp)=0.
Supported options include InitialStep, MaxStep, MinStep, RelTol, AbsTol, Refine, NormControl, OutputFcn, OutputSelection, Vectorization, MaxOrder, ComputeConsistentInitialConditions, LinearSolver, and Preconditioner. OutputFcn is called on the output points returned by the backend. LinearSolver accepts dense, iterative, and optional sparse direct SUNDIALS values when the corresponding library is available. Preconditioner accepts 'auto', 'none', 'jacobi', 'banded', or 'ilu0'. With a sparse JPattern, 'ilu0' builds a compact sparse incomplete LU preconditioner without a dense workspace.
options = nelson.ode.options.IDAS();
problem = ode('EquationType', 'fullyimplicit', ...
'ODEFcn', @(t,y,yp) yp + y, ...
'InitialValue', 1, ...
'InitialSlope', -1, ...
'SolverOptions', options);
result = solve(problem, 0, 1)| Version | Description |
|---|---|
| 2.0.0 | initial version |