Re: [Axiom-developer] code release: Bug#5977

[William Sit]

Martin and Tim:


(1) -> a:=1::DMP(['x],INT)

   (1)  1
               Type: DistributedMultivariatePolynomial([x],Integer)
(2) -> a::POLY INT

   >> System error:
   Caught fatal error [memory may be damaged]

protected-symbol-warn called with (NIL)
(2) -> variables(a)

   (2)  []
                                           Type: List OrderedVariableList [x]
(3) -> a::INT::POLY INT

   (3)  1
                                Type: Polynomial Integer

(4) -> 1::DMP([x],INT)::POLY INT


   >> System error:
   Caught fatal error [memory may be damaged]

protected-symbol-warn called with (NIL)

(5) -> 1::DMP([x],INT)::DMP([y],INT)

   (5)  1
               Type: DistributedMultivariatePolynomial([y],Integer)

and 

1::POLY INT :: DMP([x],INT) 
x::DMP([x],INT)::POLY INT
1::DMP([x,y],INT)::POLY INT 
1::EXPR INT:: POLY INT 
1::UP(x,INT)::POLY INT
 
and (surprise!) even
 
1::DMP([x],INT)::POLY FRAC INT

all worked!


This bug also exists in the NAG version, where the first (2) would give "Memory
access violation detected".  Two observations: (a) the coercion in (2), shows
the interpreter does not follow the two steps in (3); and (b) the problem is
specific to POLY INT. It may also have to do with the second (2), and my
suspicion is that it has to do with a combination of the interpreter, POLY, DMP,
INT, no variables, and may be POLYLIFT or MLIFT.

Tim: can you do a boot trace of (4) and compare that with any of the others that
work?

William