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daeoptions
set options for dae solver
Calling Sequence
daeoptions()
Description
Sets a variable %DAEOPTIONS
that is used in function dae
to set solver options.
This daeoptions function interactively displays a window which sets various options of the dae solver.
The dae function checks if this variable
exists and in this case it uses it. For using default values you should
clear this variable. Note that daeoptions does not
create this variable. To create it you must execute the command line
displayed by daeoptions . |
The variable %DAEOPTIONS
is a list with the following elements:
list(tstop,imode,band,maxstep,stepin,nonneg,isest)
The default value is:
list([],0,[],[],[],0,0)
The meaning of the elements is described below.
- solver
if it is 0,
dae
will use the dassl/dasrt solver, and if it is 1,dae
will use daskr.- tstop
a real scalar or an empty matrix, gives the maximum time for which
g
is allowed to be evaluated. An empty matrix means "no limits" imposed for time.- imode
if it is 0,
dae
returns only the user specified time point values, and if it is 1,dae
returns its intermediate computed values.- band
a two components vector which give the definition
[ml,mu]
of band matrix computed byjac
;r(i - j + ml + mu + 1,j)
=dg(i)/dy(j)+cj*dg(i)/dydot(j)
. Ifjac
returns a full matrix setband=[]
- maxstep
a scalar or an empty matrix, the maximum step size, empty matrix means "no limitation".
- stepin
a scalar or an empty matrix, the minimum step size, empty matrix means "not specified".
- nonneg
a scalar, must be set to 0 if the solution is known to be non negative . In the other case it must be set to 1.
- isest
a scalar, must be set to 0 if the given initial condition is compatible:
g(t0,x0,xdot0)=0
. Ifxdot0
is just an estimation, then set to 1 if you are using dassl, or set to[+-1, ..., +-1]
, with:1
if y(i) is a differential variable and-1
if y(i) is an algebraic variable (if its derivatives do not appear explicitly in the function g(t, y, ydot)).- method
a scalar, direct / Krylov method. Set to
1
and provide a routinepsol
indae()
if you want the solver to use Krylov iterations, else (daskr's direct method) set to0
.- Kry_params
a vector, treat as dummy argument if you have set method=0. Otherwise, set to
[]
or to[maxl kmp nrmax epli]
, where: -maxl
= maximum number of iterations in the GMRes algorithm (default min(5, neq)), -kmp
= number of vectors on which orthogonalization is done in the GMRes algorithm (default maxl), -nrmax
= maximum number of restarts of the GMRes algorithm per nonlinear iteration (default 5), -epli
= convergence test constant in GMRes algorithm (default 0.05).- init
a scalar, treat as dummy argument if you have set isest=0. Set to 1 if the solver should stop right after computation of the initial conditions, else set to 0.
- precond
a scalar, preconditioner computation and LU-factorization routine for
psol
. Treat as dummy argument if method=0. Set to 1 and provide apjac
routine indae
if the externalpsol
should use a specific routine, else set to 0.- control
a vector, treat as dummy argument if you have set isest=0if you wish to control errors locally on all the variables then set to []. Otherwise, set to [+-1, ..., +-1], 1 if
y(i)
is a differential variable and -1 ify(i)
is an algebraic variable (if its derivatives do not appear explicitly in the functiong(t, y, ydot)
).- heuristic
a vector, heuristic parameters. Treat as dummy argument if isest=0. Otherwise, set to [] or to
[mxnit mxnj mxnh lsoff stptol epinit]
, where: -mxnit
= maximum number of Newton iterations per Jacobian or preconditioner evaluation (default 5 if info(8)=0, 15 otherwise), -mxnj
= maximum number of Jacobian or preconditioner evaluations (default 6 if info(8)=0, 2 otherwise), -mxnh
= maximum number of values of the artificial stepsize parameter h to be tried if info(7) ≠ [] (default 5), -lsoff
= flag to turn off the linesearch algorithm (lsoff = 0 means linesearch is on, lsoff = 1 means it is turned off) (default 0), -stptol
= minimum scaled step in linesearch algorithm (default (unit roundoff)^(2/3)), -epinit
= swing factor in the Newton iteration convergence test (default 0.01).- verbosity
a scalar, verbosity. Set to 1 for minimal extra printing, 2 for full printing, else set to 0.
See Also
- dae — Differential algebraic equations solver
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