Problem with minuses in tensor library's ex_calc.mac

Thank you for those fixes! I have incorporated them into the CVS version,
and I am not observing any ill effects either.

Unfortunately, I don't think it is possible to include your fix in the
5.14.0 release; we are too late for that. I think that's okay, since the
code fails gracefully, in that it prints a valid error message, as opposed
to producing an incorrect result.


Viktor



-----Original Message-----
From: maxima-bounces at math.utexas.edu [mailto:maxima-bounces at math.utexas.edu]
On Behalf Of josie.huddleston at durham.ac.uk
Sent: Saturday, December 22, 2007 7:35 PM
To: maxima at math.utexas.edu
Subject: Problem with minuses in tensor library's ex_calc.mac

I've come across an issue that'll hopefully fix fairly easily: the functions

covind and contind in ex_calc.mac (in the tensor share library) both get
thrown 
by things with a minus operator.  I've had a quick look, and I reckon it'll
fix 
the problem if you add the following lines:

Between lines 110 and 111:
else if op(t)="-" then covind(part(t,1))

Between lines 93 and 94:
else if op(t)="-" then contind(part(t,1))

I've added these changes on my copy, with no apparent ill effects so far...

The problem doesn't show up in ex_calc.dem, I think because some of the
terms 
in all these examples are positive so it just ignores the anomalous result
of 
the negative ones somehow.

Is it too late to get this changed for the new version?  Fingers crossed...!


               Josie
_______________________________________________
Maxima mailing list
Maxima at math.utexas.edu
http://www.math.utexas.edu/mailman/listinfo/maxima