MathAction #271 )show Expression Boolean gives a list



#271 )show Expression Boolean gives a list
last edited 17 years ago by gdr

Submitted by : (unknown) at: 2007年11月17日T22:19:14-08:00 (18 years ago)
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As I was looking for boolean simplification, I type )sh Expression Boolean. I get the list of the real expressions. So I type

fricas
(1) -> sin (A::Expression Boolean) or true.
Line 1: sin (A::Expression Boolean) or true. ...................................A Error A: syntax error at top level Error A: Improper syntax. 2 error(s) parsing

Axiom disapproves

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

And the axiom process died the command-line after.

cannot reproduce axiom process died --Bill Page, 2006年2月27日 12:37:15 -0600 reply
I can not reproduce your observation that:
the axiom process died the command-line after.

This does not happen for me on at least the Windows version of Axiom.

But I do find it very odd that Axiom allows the construction of the domain Expression Boolean without complaint:

fricas
x:Expression Boolean:=true
Type: Expression(Boolean)

The scary sounding message: 'Caught fatal error [memory may be damaged]?' occurs for many operations applied to this object.

The definition of the constructor Expression R: OrderedSet seems wrong to me since there are may operations exported by Expression that are not naturally interpreted over a domain that is just an OrderedSet. For example Boolean is considered ordered as follows:

fricas
Boolean has OrderedSet
Type: Boolean
fricas
true > false
Type: Boolean

although we might also question the wisdom of considering Boolean ordered in this way.

#271 )show Expression Boolean gives a list cannot reproduce axiom process died --root, 2006年3月03日 10:02:57 -0600 reply
I've been running thousands of integrals thru axiom recently. There is a problem related to interrupting Axiom while garbage collection is running (I'm guessing) and, very occasionally, Axiom will generate an error or die completely (only once so far). However if Axiom is not interrupted I have yet to see it fail.

The "memory may be damaged" message occurs quite often but I have yet to see any surface damage on the DIMM packages :-). I'm not sure why Bill thought this was a reasonable error message but it does not seem to be a problem. Only console interrupts have caused failure so far and those seem to be related to some race condition in garbage collection.

Tim

fixed in FriCAS --kratt6, 2008年1月19日 00:52:27 -0800 reply
Status: open => fix proposed

... --gdr, 2008年5月18日 13:25:45 -0700 reply
Status: fix proposed => fixed somewhere

no patch available

Patch from Fricas --alfredo, 2008年10月16日 03:38:56 -0700 reply
http://fricas.svn.sourceforge.net/viewvc/fricas/trunk/src/interp/i-coerce.boot?r1=105&r2=189&view=patch

Fixed in OpenAxiom --gdr, 2008年10月17日 16:52:24 -0700 reply




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