CAS memory corruption (6975)

[Snorre]

Hello,

(12-31-2014 03:04 PM)parisse Wrote:  I will investigate. [...]

Thank you.
I made some further tests and could create even more simplistic examples that may help to isolate the problem.

Ex. 1 (observation):
r(n):=sum_riemann(1,[k n])
r(numericterm) gives a warning about creation of a substitution variable which should be purged manually.
This warning does not occur when calling r(symbolicterm) despite a substitution variable was created too.

Assumption 1:
If the upper limit of sum is a symbolic term a substitution variable remains in memory.

Ex. 2
s(n):=sum(1,k=1..n)
s(symbolicterm) creates a substitution variable (matrix k=[[DOM_SYMBOLIC]]), whereas s(numericterm) does not.
Ex. 3
s(n):=sum(1/2^k,k=1..n)
s(symbolicterm) and s(numericterm) behave like Ex. 2, but
s(∞) corrupts memory.

Assumption 2:
This subsitution variable does not cause further problems as long as it gets a valid name (e.g. "k").
CAS memory corruption is due to invalid variable names "□", "□(□", "#" as described in the first postings (and by s(∞) in Ex. 3 which created a matrix named "4").

Integration behaviour seems similiar to sum (but with exchanged roles of the argument type):
Ex. 4
f(u):=int(1/2^x,x=0..u)
f(numericterm) and f(∞) create a substitution variable "x" but no further problems,
f(symbolicterm) does not.

Assumption 3:
Since all these substitution variables do only appear/remain if the sum/integral is within a function, there seems to be an issue with internal clean-up routine (as assumed in first posting).

Before doing each example the CAS was cleared by hand (in memory manager) and an additional "restart" was invoked.
The CAS-settings were: "Exact", "Use √", "Principal", "Simplify: None".

It's a pity that I didn't check the memory when doing the examples of first two posting for the first time (it was near dec 2013 with then up-to-date firmware).
But as I don't remember having any problems, I'd think it is related to some recent firmware changes.
I hope you can reproduce that behaviour. I love my Prime and am pretty sure it's a minor bug.
(Sidenote: a CFO-reset didn't help.)

Greetings

P.S. I was sloppy about naming things: numericterm means some term like "1.0", "2", "3/4", "ln(5)", etc.; symbolicterm means some term containing a free variable, infinity, etc.