how to evaluate with certain conditions and how to use arrays instead of separate variables

Robert,

thanks for your help.

I applied your changes.
But I'm still getting an error.
I've already installed a newer version of maxima
(after trying unsuccessfully to get two different windows version to run).
I'm using Ubuntu 64bit and I downloaded and compiled maxima myself
-- after having fought with gcl for a while
-- I've used some environment variable to enable ANSI mode for gcl:
setenv GCL_ANSI 1

For the error see below.
The system is certainly not running out of memory!

See attached..

Thanks for doing my job! (grin)
Peter


Maxima 5.27.0 http://maxima.sourceforge.net
using Lisp GNU Common Lisp (GCL) GCL 2.6.7 (a.k.a. GCL)
Distributed under the GNU Public License. See the file COPYING.
Dedicated to the memory of William Schelter.
The function bug_report() provides bug reporting information.
(%i1) 
(%i2) 
(%i3) 
(%i4) 
(%i5) 
(%i6) 
(%i7) 
(%i8) 
(%i9) 
(%i10) 
(%i11) 
(%i12) 
(%i13) 
(%i14) 
(%i15) 
(%i16) 
(%i17) 
(%i18) 
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Maxima encountered a Lisp error:

 Error in PROGN [or a callee]: The storage for CONS is exhausted.
Currently, 186935 pages are allocated.
Use ALLOCATE to expand the space.

Automatically continuing.
To enable the Lisp debugger set *debugger-hook* to nil.
(%i23) 
Maxima encountered a Lisp error:

 Error in MREAD-RAW [or a callee]: The storage for SPICE is exhausted.
Currently, 6123 pages are allocated.
Use ALLOCATE to expand the space.

Automatically continuing.
To enable the Lisp debugger set *debugger-hook* to nil.
(%i23) incorrect syntax: Too many )'s
iffSpace(int1_,Spacex,Space1))
                ^
(%i23) 
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join: both arguments must be lists.
 -- an error.  Entering the Maxima debugger.
Enter ':h' for help.
(dbm:1) 
false
(dbm:1) 
false
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