Exponentiation used in division? & Some extrordinary slowness is some problems.

I find the documentation on modedeclare and compile a little confusing.
Could someone point me to a short working example?
I've never done that before.

I have no idea how to produce a short example of my problem and I 
suspect it may be too large to even attach.
I cannot expect anyone to tackle this - but I will provide some links 
just in case.

(These are just in the 2nd recent set of tests -  have been working on 
this in one form or another for a long time.)

The maxima source file:
http://sode.sourceforge.net/omniresults/2nd_maxima_tests/diffeq.expt_lin_sin_new.max.txt

The results:
http://sode.sourceforge.net/omniresults/2nd_maxima_tests/results.expt_lin_sin_new.max.txt

The c source for the same problem:
http://sode.sourceforge.net/omniresults/2nd_c_tests/diffeq.expt_lin_sin_new.c.txt

The c program results:
http://sode.sourceforge.net/omniresults/2nd_c_tests/results.expt_lin_sin_new.c.txt

Both programs are generated by the same set of programs.

Again there is more info at the web site - it will be difficult to 
understand the code without the info.
http://sode.sourceforge.net/
I really don't expect anyone to tackle this but help on compiling would 
be appreciated.



Dennis Darland
student at dennisdarland.com

On 12/31/2013 5:18 PM, Stavros Macrakis wrote:
> modedeclare is useful when the Maxima+Lisp compilers can take 
> advantage of a more efficient representation or more efficient 
> operations than those used by the interpreter.
>
> That is the case for some kinds of numbers (though not bfloats) and 
> some kinds of arrays.
>
> There is no way to declare an argument as a string, or a symbol, or as 
> a list, etc., because the Maxima+Lisp compilers don't know how to take 
> advantage of that information.  You can still compile functions whose 
> arguments and internal variables are not modedeclare'd -- it's just 
> that the speed-up will be smaller.
>
> Again, we should be able to help you improve the performance of your 
> code if you can give us a /short, self-contained, reproducible /example.
>
>              -s
>
>
> On Tue, Dec 31, 2013 at 5:51 PM, Dennis Darland - student 
> <student at dennisdarland.com <mailto:student at dennisdarland.com>> wrote:
>
>     I have functions to which I pass strings. I see no type for them.
>     Does that mean I can not use modedeclare?
>     I saw that you can pass only some functions (instead of all) to
>     compile, does that mean I could compile all except those
>     containing strings and still run the program?  If not there is no
>     use in trying it.
>
>     There are over 100 programs in my test suite. Only two take
>     anything like this long. They are quite long complex  programs but
>     so are many of the others.
>
>     I am not very concerned about this as I can use the other
>     languages, and I have learned a lot in the process.
>
>     Dennis Darland
>     student at dennisdarland.com <mailto:student at dennisdarland.com>
>
>
>     On 12/31/2013 12:04 PM, Dennis Darland - student wrote:
>
>         I've decided to try modedeclare. If I remember correctly, I
>         could not use bfloat in declare_variable either. I will
>         try to isolate the changes however. I only have one program to
>         generate c, c++, Ruby, Maxima or Maple.
>
>         Dennis Darland
>         student at dennisdarland.com <mailto:student at dennisdarland.com>
>
>         On 12/31/2013 11:08 AM, Robert Dodier wrote:
>
>             On 2013-12-31, Dennis Darland - student
>             <student at dennisdarland.com
>             <mailto:student at dennisdarland.com>> wrote:
>
>                 I do not expect maxima to be comparable to c at number
>                 crunching,
>                 but there are two examples in my tests that it appears
>                 would take over
>                 one day to complete using maxima, but take only 4 and
>                 5 seconds
>                 respectively in c.
>
>             A major factor is that Maxima is probably doing something
>             much more
>             general than necessary. Speeding up the code would require
>             recognizing
>             that a special case is possible and then exploiting it.
>             Maxima has some
>             machinery for that, but it is clumsy to use and not
>             terribly effective.
>             I certainly agree that getting Maxima to run faster is a
>             good idea, but
>             at present we (developers) are mostly concerned with
>             trying to get it
>             to run correctly first. If you would like to work on
>             speed, though, you
>             are more than welcome to do so.
>
>             best
>
>             Robert Dodier
>