Hp50g global min and max solver

[Gjermund Skailand]

Hi all. I have a global maximum and minimum and root solver for
smooth continous functions for the hp50g and are looking for beta-testers.
The solver is written in hpgcc3.
The solver works as follows:
The function is sampled with a custom parser and a fast Chebyshev transformation.
Then all roots are simultaneously solved through the eigenvalues of the (implicit) companion matrix. The eigenvaluesolver typically solves a 65 degree problem in less than 1 sec. The solver is a fast type using linear memory and typically samples at 129 degree.
The solver is recursively.
There are also some utilities for chebyshev trasformation, integation,derivation and plotting.
These are based on fast fft or dct tranforms.
Regarding speed:
1025 degree sampling, transformation and plotting of e.g.
SIN (5*PI*x) in standard intervall -1 .. 1
is done in about 2 sec.

The solver was inpired by the chebfun system, however this one runs on the calculator.
However you need to install a custom hpgcc3 rom.
Anyone interrested, please let me know.
Best regards
Gjermund

[rkf]

I still remember Gjermund's brilliant Curve Fitting Library (for the HP48/49, April 2000) and thus I'm absolutely sure his new global maximum and minimum and root solver is also unbeatable regarding efficiency.

Yet installing a custom ROM version is a non neglectable obstacle, at least for me. But I really hope that nevertheless some volunteers support the beta testing. Good luck!

[Claudio L.]

(02-18-2015 08:52 AM)rkf Wrote:  Yet installing a custom ROM version is a non neglectable obstacle, at least for me. But I really hope that nevertheless some volunteers support the beta testing. Good luck!

I don't understand why it would be an obstacle. I haven't used an hpgcc3 program in several years, yet my calculator has been running the modified ROM since 2006. The changes have NO consequences in normal operation, it does not affect your results in any way, doesn't crash, etc since hpgcc3 is completely outside the Saturn world. All you lose is one user flash bank, which is taken by hpgcc3 libraries.
The only change is when you EVAL an ARMCode object. Everything else is the same good old rom.

Claudio

[Gjermund Skailand]

The rom which I have included in the distribution is actually HP50-C rev 2.15 amended with the hpgcc using some additional flash. See http://www.hpgcc3.org for details.
It installs from the sd card like any other rom.
To make the upgrade worth the effort I'll throw in an additional linear matrix library with general eigenvalue solvers and matrix exponentials. This is far beyond what exist in rom for numerical solvers and at least 100x faster than the originals.
Any takers?
best regards
Gjermund