Modifiable Options within the gfun Package - Maple Help

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Modifiable Options within the gfun Package

 

Calling Sequence

Parameters

Description

Examples

Calling Sequence

Parameters(arg1, arg2, ... )

Parameters

arg1, arg2, ...

-

argument(s) of the form name=val or name

Description

• 

The Parameters command is used to set and query variables that affect the computation inside gfun. The variables that can be set and queried are as follows.

maxdegcoeff

maxordereqn

maxdegeqn

mindegcoeff

mindegeqn

minordereqn

optionsgf

 

• 

If an argument is of the form name=val then this specifies the setting for the named variable.

  

For each argument of this type, Parameters returns the old value of the argument.  This is convenient when you want to change and later restore a value, for example,

  

 

oldorder := Parameters(maxordereqn=7);    # set new value and save old

...

Parameters(maxordereqn=oldorder);         # restore previous value

• 

If an argument is a name then the current value of the named variable is retrieved and returned as the function value.

• 

When Parameters is called with many arguments, it returns an expression sequence containing the values.

• 

The standard set of Parameters variables is:

NAME

VALUES

EXPLANATION

 

 

 

maxdegcoeff

nonnegint

the maximal degree of the coefficients of equations returned by listtodiffeq, listtoalgeq, seriestodiffeq, and seriestoalgeq.  The default value is 4.

maxdegeqn

nonnegint

the maximal degree for polynomial equations returned by listtoalgeq and seriestoalgeq.  The default value is 3.

maxordereqn

nonnegint

the maximal order for differential equations returned by listtodiffeq and seriestodiffeq.  The default value is 3.

mindegcoeff

nonnegint

the minimal degree of the coefficients of equations returned by listtodiffeq, listtoalgeq, seriestodiffeq, and seriestoalgeq.  The default value is 0.

mindegeqn

nonnegint

the minimal degree for polynomial equations returned by listtoalgeq and seriestoalgeq.  The default value is 2.

minordereqn

nonnegint

the minimal order for differential equations returned by listtodiffeq and seriestodiffeq.  The default value is 1.

optionsgf

list

specifies the list of types of generating functions considered by listtoalgeq, listtodiffeq, listtohypergeom, listtolist, listtoratpoly, listtorec, listtoseries, seriestoalgeq, seriestodiffeq, seriestohypergeom, seriestolist, seriestoratpoly, seriestorec, and seriestoseries.

 

 

The default is ['ogf', 'egf'] (ordinary and exponential generating functions).

  

For more information on the generating function types, see gfun/gftypes.

  

For example, if the listtodiffeq function is used, only those linear differential equations whose order is between minordereqn and maxordereqn and whose coefficients have a degree between mindegcoeff and maxdegcoeff are considered.

• 

Similarly, maxdegeqn and mindegeqn are used to bound the degree of algebraic equations.

• 

Note, the old way of changing parameters by assigning the values to gfun:-<option> is deprecated.

Examples

gfun:-Parameters&apos;maxordereqn&apos;&equals;5&comma;mindegcoeff

3&comma;0

(1)

See Also

gfun

gfun/gftypes

 


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