🚀 go-pugleaf

-----On 17 Aug 90 22:16:48 GMT, usenet@nlm.nih.gov (David States) said:

David> Generation of standard Fortran or C code to evaluate an
David> algebraic expression has been a standard feature of symbolic
David> algebra programs such as MACSYMA for at least 15 years.
David> Mathmatica supports similar functionality.  I have never seen
David> it used much.  Anyone care to speculate on why this is?

Because they generate extremely inefficient code (at least Mathematica 
does-- I have very little experience with Macsyma).  For instance, I
periodically use Mathematica to generate partial derivatives.  I then
output expressions in some human readable format and edit them 
extensively to turn them into semi-efficent C code.

Part of the problem is that Mathematica's expression simplification
function doesn't work very well at all.  And for generating code, some
techniques should be used, such as common subexpression elimination,
to turn a single algebraic expression into more than one line of code.

Another part of the problem is I dislike the coding style that
Mathematica outputs.  The code requires use of a set of C macros
(supplied), but would make that section of code's style different from
anything else in our program, which is a distinct code maintenance
disadvantage.

Were I using FORTRAN, I'd be much better served by an automatic code
differentiation package, such as NETLIB's JAKEF.

--
Steve Hamm ----------- Motorola Inc. Semiconductor Sector CAD  
                       3501 Ed Bluestein Blvd., MD-M2, Austin TX 78762
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