CompuServe Thread

#Speed

4 messages in this thread
#115315From: Ingo NeumannJul 30, 1994 5:13 PM
Hi Ed, I hope you use POE libs for calculating your chaos and collisions in AniPro. If not you should do this, because POE libs run 3 times faster as the orginal POCO code. Ingo
#115440From: Ed KellermanJul 31, 1994 11:19 PM
<Hi Ed, I hope you use POE libs for calculating your chaos and collisions in AniPro. If not you should do this, because POE libs run 3 times faster as the orginal POCO code.> Hi Ingo. I haven't used POE yet. Do you mean that there are libraries already available for some of these calculations? Right now I am experimenting a lot, and modifying the code after each run. Would I still want to use POE in that case? If you don't mind, I would appreciate hearing more details on what's involved. Here are more details on what I am doing: I got started by looking through my books on how to calculate the motion, under gravity, for several objects, and couldn't find anything. So, I made a few back of the envelope manipulations (starting with 1/2*g*t*t) and tried what I got. The results were so interesting that I haven't had the time to recheck the equations, and assumptions, I am using. Do you know where I could find a description of how to calculate these trajectories? By the way, I'll send my programs to anyone who would like to try them. The program I am working on right now, calculates trajectories for two galaxies whose mass is concentrated at one point. One of the galaxies has about 180 stars. The stars are influenced by the two masses, but generate no gravity field themselves. I'm trying to reproduce the results in "Violent Tides Between Galaxies" from Scentific American of 12/73. They show that close approaches can generate galaxies with spiral arms. The problem I am having, is that as soon as I start one galaxy, with stars in random positions, all rotating in the same direction and at speeds that result in stable circular orbits, the darn thing develops spiral arms ON ITS OWN (before the other galaxy approaches it). Let me know what you think. Ed K
#115808From: Ingo NeumannAug 2, 1994 4:17 PM
Ed, I am not the man for math problems in galaxies, that doesn't mean that Iam not intressted in it. I read a lot of books about the begining universe, micro/mkro kosmos, but without any aspct of math. Perhaps you sould ask the NASA or a astronomic institute for more infos. I know that the collision of galaxies was already calculated and visualisted in super computers. Back to the POE'S. POCO is an interpreter, that means your POCO (C) code will be translated into CPU instructions during runtime. You lost a lot of CPU power for this translations but you have the atvantage manipulate your code suddendly. A POE lib is nearly the same POCO code, but it's translated before starting the main POCO program, so you can use the full CPU speed for extensive calculation like chaos algorithems or particle systems. To create your own POE's you need a C-Complier like METAWARE HIGH C and the PHARLAP DOS EXTENDER/LINKER. After compiling your code you can use it as a C function in POCO. Because the time intensive code is already compiled you run in full CPU speed. I tested this with the mandelbrot algorithem which run 3 times faster with POE precompiling. OK, that should be enougth for the moment. BTW, ANIMATOR's POCO is a great tool to program some small utilities into Animator. For grater Animator independent software, you should use a REAL C Compiler with a userinterface and an EDITOR!!, debugger, ………………. This is more productive for your work. When you have finished you can esaliy import the main routines into POCO and use the atvantage of image/Filc support. Ask your dealer for the AUTODESK FLIClib for support outside Animator and the POE KIT. Welcome in the wonderful world of software engeniering 🙂 I know Animators POCO interpreter is easiy to handle compared with a real compiler, but belive me, after 500 lines source code a real compiler is better. (My greates POCO has 1500 lines, then I loose the overview<g>). If you like, and I have some time, I can compile the time intensive routines of your POCO into a POE. Ingo
#116442From: Ed KellermanAug 4, 1994 10:16 PM
Sorry for the delay in replying. I haven't done much else since I figured out how to use AniPro/POCO to play with Chaos and Galaxies. <to create your own POE's you need a C-Compiler like METAWARE HIGH C and the PHARLAP DOS EXTENDER/LINKER.> You talked me into it! But the price is a shocker! I called Pharlap today to order the linker and found that it is part of a $500 SDK that includes a C compiler. I already have the Watcom C compiler (bought it to try my hand at IPAS routines, but never got to it). Is there a cheaper way to get all I need (without paying for another C-compiler)?. Whatever I get should work for IPAS also. The galaxy stuff might be headed that way. <I am not the man for math problems in galaxies> I finally took the time to figure it out, and I have it all working now. <If you like, and I have some time, I can compile the time intensive routines of your POCO into a POE.> Thanks. I may take you up on the offer. But I have a problem. I modify many parameters like galaxy/star positions, velocity, colors, etc. by simply editing the POCO code. If I compile the code, I would need an alternate way to edit parameter values. POCO only seems to provide a way for the user to enter one value at a time. Any thoughts? Ed K