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See the recommended documentation of this function
odeoptions
set options for ode solvers
Calling Sequence
odeoptions()
Description
This function interactively displays a command which should be
executed to set various options of ode solvers. The global variable
%ODEOPTIONS
sets the options.
CAUTION: the ode
function checks if this variable
exists and in this case it uses it. For using default values you should
clear this variable. Note that odeoptions
does not
create this variable. To create it you must execute the command line
displayed by odeoptions
.
The variable %ODEOPTIONS
is a vector with the
following elements:
[itask,tcrit,h0,hmax,hmin,jactyp,mxstep,maxordn,maxords,ixpr,ml,mu]
The default value is:
[1,0,0,%inf,0,2,500,12,5,0,-1,-1]
The meaning of the elements is described below.
itask
1 : normal computation at specified times 2
: computation at mesh points (given in first row of output of
ode
) 3 : one step at one internal mesh point and return
4 : normal computation without overshooting tcrit
5 :
one step, without passing tcrit
, and return
tcrit
assumes itask
equals 4
or 5, described above
h0
first step tried
hmax
max step size
hmin
min step size
jactype
0 : functional iterations, no jacobian
used ("adams"
or "stiff"
only) 1 :
user-supplied full jacobian 2 : internally generated full jacobian 3 :
internally generated diagonal jacobian ("adams"
or
"stiff"
only) 4 : user-supplied banded jacobian (see
ml
and mu
below) 5 : internally
generated banded jacobian (see
ml and
mu
below)
maxordn
maximum non-stiff order allowed, at most
12
maxords
maximum stiff order allowed, at most
5
ixpr
print level, 0 or 1
ml
,mu
If
jactype
equals 4 or 5, ml
and
mu
are the lower and upper half-bandwidths of the
banded jacobian: the band is the i,j's with i-ml <= j <= ny-1. If
jactype
equals 4 the jacobian function must return a
matrix J which is ml+mu+1 x ny (where ny=dim of y in ydot=f(t,y)) such
that column 1 of J is made of mu zeros followed by df1/dy1, df2/dy1,
df3/dy1, ... (1+ml possibly non-zero entries) column 2 is made of mu-1
zeros followed by df1/dx2, df2/dx2, etc
See Also
<< odedc | Differential Equations, Integration | Elementary Functions >> |