Hi All,
Does anybody understand why the following fails?
-- test2.spad ----------------------------------
)abbrev package TEST2 Test2
Test2 : Exports == Implementation where
R ==> Fraction Integer
Exports == with
listCoeffs: Polynomial(R) -> List(R)
Implementation == add
listCoeffs p ==
v : Symbol := variables(p).1
d : NonNegativeInteger := degree(p,v)
[coefficient(p,v,n) for n in 0..d]
------------------------------------------------
When I attempt to )compile it I get:-
****** comp fails at level 1 with expression: ******
error in function listCoeffs
((|coefficient| |p| |v| |n|))
****** level 1 ******
$x:= (coefficient p v n)
$m:= (Fraction (Integer))
$f:=
((((|n| # #) (|d| #) (|v| #) (|last| #) ...)))
>> Apparent user error:
cannot compile (coefficient p v n)
and similarly, if I put the code in a .input file as:-
-- test2.input ---------------------------------
R ==> Fraction Integer
listCoeffs: Polynomial(R) -> List(R)
listCoeffs p ==
v : Symbol := variables(p).1
d : NonNegativeInteger := degree(p,v)
[coefficient(p,v,n) for n in 0..d]
------------------------------------------------
then )read works, but when I try to call the function I get:-
(4) -> f : POLY(Fraction Integer) := 3*x^2 + 1
2
(4) 3x + 1
Type:
Polynomial(Fraction(Integer))
(5) -> listCoeffs f
There are 2 exposed and 2 unexposed library operations named
coefficient having 3 argument(s) but none was determined to be
applicable. Use HyperDoc Browse, or issue
)display op coefficient
to learn more about the available operations. Perhaps
package-calling the operation or using coercions on the arguments
will allow you to apply the operation.
Cannot find a definition or applicable library operation named
coefficient with argument type(s)
Polynomial(Fraction(Integer))
Symbol
NonNegativeInteger
Perhaps you should use "@" to indicate the required return type,
or "$" to specify which version of the function you need.
FriCAS will attempt to step through and interpret the code.
Compiling function listCoeffs with type Polynomial(Fraction(Integer)
) -> List(Fraction(Integer))
There are 2 exposed and 2 unexposed library operations named
coefficient having 3 argument(s) but none was determined to be
applicable. Use HyperDoc Browse, or issue
)display op coefficient
to learn more about the available operations. Perhaps
package-calling the operation or using coercions on the arguments
will allow you to apply the operation.
Cannot find a definition or applicable library operation named
coefficient with argument type(s)
Polynomial(Fraction(Integer))
Symbol
NonNegativeInteger
Perhaps you should use "@" to indicate the required return type,
or "$" to specify which version of the function you need.
but looking at the SPAD source code in multpoly.spad and polycat.spad
I see there is a default implementation of coefficient(p,v,n) in the
PolynomialCategory(R,E,VarSet) definition. What's more, if I evaluate
each line of the function manually at the REPL then things work.
This is in FriCAS 1.2.6. Am I doing something stupid?
Any pointers appreciated,
Paul
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