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HP Forum Archive 14

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Linear Programming
Message #1 Posted by Guillermo Castarés on 30 Apr 2004, 3:19 p.m.

I want to know if is possible to find a calculator program to solve "Linear Programming" problems. I didn´t studied the Simplex algorithm yet, so I am not sure if is possible to put it on HP-41/42 series. Any comment?

      
Re: Linear Programming
Message #2 Posted by Jean-Marc on 30 Apr 2004, 3:50 p.m.,
in response to message #1 by Guillermo Castarés

Hi! I can recommend you my "simplex" HP-41 program in the HP-41C Library... Regards.

            
Re: Linear Programming - some questions ;)
Message #3 Posted by Vieira, Luiz C. (Brazil) on 30 Apr 2004, 5:00 p.m.,
in response to message #2 by Jean-Marc

Hi, Jean-Marc;

first of all, congrats! Your Simplex program for the HP41 is a nice piece of art! Clean, concise and explores many of the HP41 software capabilities.

I did not have the time to go further and analyse it, but I wonder about one thing: have you used synth instructions in order to use system registers and leave all numbered registers available OR is there any particular need? I mention again that I did not analyse the program "in deep", but I decided to ask you first before getting to wrong conclusions ;^)

Another issue: have you thought about Operational Research and Linear Programming as well? Simplex is one of the methods. I've been reasoning about developing some sort of a portable GAMS (or LINDO) version to run in an HP49G; as I am about to get an HP49G+ with extra RAM memory, so I think it's something to be considered. I used an HP49G to hold some small programs to be used in Fuzzy Logic and Artificial Neural Networks, but I never put them together in order to form a complete system. I'm daring to go ahead with Operational Research. Have you done something in this area as well?

BTW, folks, if there is anyone interested in this subject, let's just start a thread.

Cheers and thanks.

Luiz (Brazil)

                  
Re: Linear Programming - some questions ;)
Message #4 Posted by Arnaud Amiel on 1 May 2004, 2:36 a.m.,
in response to message #3 by Vieira, Luiz C. (Brazil)

Quote:
version to run in an HP49G; as I am about to get an HP49G+ with extra RAM memory

Careful, the 49g+ has actually less RAM available to the user than the 49. But it is much faster.

Arnaud

                        
Re: Linear Programming - some questions ;)
Message #5 Posted by Vieira, Luiz C. (Brazil) on 1 May 2004, 9:08 a.m.,
in response to message #4 by Arnaud Amiel

Hi, Arnaud;

thank you for your warnning!

If you plug a RAM card on an HP49G+, how is it this RAM seen by the O.S.? I'm asking this because if its contents can be handled as some sort of "extension" (as it happens in BANK 1 of the HP49G), I guess it will do fine running programms in main memory and data in this "extra" RAM. I remember that I was worried about speed in this case, but I never took any performance measurement. Any information about this?

Thank you again.

Cheers.

Luiz (Brazil)

                              
Re: Linear Programming - some questions ;)
Message #6 Posted by Arnaud Amiel on 1 May 2004, 9:34 a.m.,
in response to message #5 by Vieira, Luiz C. (Brazil)

The 49g+ has 256K RAM in port 0 128K RAM in port 1 as the other 128K are used by the ARM in some way about 765K FLASH in port 2 Whatever you want in SD card port 3

However the size of programs or data is limited to 128k and no library can be executed from the SD card.

I hope this helps

Arnaud

                                    
Perfect! That's what I needed to know! d;^)
Message #7 Posted by Vieira, Luiz C. (Brazil) on 1 May 2004, 1:09 p.m.,
in response to message #6 by Arnaud Amiel

...

                  
Re: Linear Programming - some questions ;)
Message #8 Posted by Jean-Marc on 1 May 2004, 4:15 p.m.,
in response to message #3 by Vieira, Luiz C. (Brazil)

Hi! Thank you! I've used synthetic registers for 2 reasons: 1°) Larger problems can be solved. 2°) The 1st coefficent is stored in R01 and finally, x1 is in R01 ... xn is in Rnn which is more logical. I do not have an HP-49 but I do have an HP-48 and I've written a Simplex program for the HP-48GX a couple of weeks ago. If you are interested, I can send you a copy of this program ( I think it will work on an HP-49 too ). Regards.

                        
Re: Linear Programming - some questions ;)
Message #9 Posted by Veli-Pekka Nousiainen on 1 May 2004, 5:28 p.m.,
in response to message #8 by Jean-Marc

" I've written a Simplex program for the HP-48GX a couple of weeks ago. If you are interested, I can send you a copy of this program"

I'm also interested...just DROP LETTER
[VPN}

                        
Re: Linear Programming - some questions ;)
Message #10 Posted by Vieira, Luiz C. (Brazil) on 1 May 2004, 7:30 p.m.,
in response to message #8 by Jean-Marc

Hello Jean-Marc, Velli-Pekka, folks;

Yes, I'm much interested on your program (I added my e-mail address in the end of the post). Can I "dig it" and try to reason over the algorithm you use?

I'm actually starting to deal with Operational Research for academic matters, and there are other solution methods I'm gonna work with. Simplex is one of them, and I would like very much to see how did you accomplish the task of programming it in RPL. As I'm getting through it I'm posting messages, if there is any interest on this subject by you or others.

Veli-Pekka, are you dealing with related subjects as well? Just curiosity of mine.

Cheers.

Luiz (Brazil) lcvieira@quantica.com.br

                              
Re: Linear Programming - some questions ;)
Message #11 Posted by Veli-Pekka Nousiainen on 2 May 2004, 4:21 a.m.,
in response to message #10 by Vieira, Luiz C. (Brazil)

"Veli-Pekka, are you dealing with related subjects as well? Just curiosity of mine."

No, I have been in IT business about 20 years, programming professionally using several languages:
Basic (MS Visual ; 71B), Cobol, EasyTrieve, Eiffel, FAS (Fortran-Assembler - developed in Finland), K-mies (K-man), SQL, Survo scipts
AND semi-pro:
Assembler (71B), Comal (Commodore Pascal), SysRPL (49G), UserRPL (48GX)
Official Training on following:
C, Cobol, Eiffel, Fortran, Mixal, Pascal, RPG II, SQL, UNIX shell scripts
Hobby: ARexx, Assembler, Basic, Forth, Macro or script languages (Amiga, DOS, Unix), DOSUserRPL, SysRPL

I may have forgotten a few (both from the list and "how to program" of those in the list)
As a semi-pro I currently help 4x users in Finland.
[VPN]

            
Re: Linear Programming
Message #12 Posted by Guillermo Castarés on 3 May 2004, 9:36 a.m.,
in response to message #2 by Jean-Marc

Thanks Jean and the others. I will load the program a.s.a.p. (first I have to remember how to work with synthetic programming) to start to play with it.

Guillermo

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