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-   -   I need a serious workhorse computer for complex simulations (http://archives1.twoplustwo.com/showthread.php?t=550320)

Neuge 11-20-2007 02:22 AM

Re: I need a serious workhorse computer for complex simulations
 
After your data is loaded from the files on the HD, is there a lot of reading and writing to the HD during the simulation?

Ganjasaurus Rex 11-20-2007 02:26 AM

Re: I need a serious workhorse computer for complex simulations
 
Ok, i get what you're asking. It doesn't seem to be the case based on the lack of noise in the hard drive during the simulation.

Neuge 11-20-2007 02:32 AM

Re: I need a serious workhorse computer for complex simulations
 
Not to be offensive, but you don't seem to be able to determine the hardware you need (obv why you're asking). Let me see if I can figure it out.

What exactly does the simulation do? What operating system are you running? Do you have access to the source code? Do you know the parallelization (eg. MPI, OpenMP)?

Ganjasaurus Rex 11-20-2007 02:42 AM

Re: I need a serious workhorse computer for complex simulations
 
You're absolutely right, in that i don't know what i need. The more i think about it, the more i realize that i'm lost and need more guidance before purchasing the right computer.

I'll try to answer your questions.

The simulation is mimicking 200,000 typical statistical "experiments" (well, each permutation is). To be specific, i believe that the statistic P-replication (P-rep) underestimates the true probability of replication. Thus, i've created 200,000 "experiments" using various population parameters (permutations of effect sizes) to determine what the actual probability of replication is, and then compare the mean/median of those to what P-rep predicts. The experiments are basically t-tests with an n = 10, 20, 40, and 100. They are all running simultaneously in the program. The program is written in C++. I didn't write (my programmer did), but i do have access to the source code if necessary.

Sorry, i don't know what "parallelization (eg. MPI, OpenMP)" means.

Thanks for your help in this. I do appreciate it.

rubbrband 11-20-2007 02:53 AM

Re: I need a serious workhorse computer for complex simulations
 
wonder if it's worth it to overclock with a badass cooling system?

Neuge 11-20-2007 02:57 AM

Re: I need a serious workhorse computer for complex simulations
 
[ QUOTE ]
You're absolutely right, in that i don't know what i need. The more i think about it, the more i realize that i'm lost and need more guidance before purchasing the right computer.

I'll try to answer your questions.

The simulation is mimicking 200,000 typical statistical "experiments" (well, each permutation is). To be specific, i believe that the statistic P-replication (P-rep) underestimates the true probability of replication. Thus, i've created 200,000 "experiments" using various population parameters (permutations of effect sizes) to determine what the actual probability of replication is, and then compare the mean/median of those to what P-rep predicts. The experiments are basically t-tests with an n = 10, 20, 40, and 100. They are all running simultaneously in the program. The program is written in C++. I didn't write (my programmer did), but i do have access to the source code if necessary.

Sorry, i don't know what "parallelization (eg. MPI, OpenMP)" means.

Thanks for your help in this. I do appreciate it.

[/ QUOTE ]
Okay, first let me see if I understand this. You're running a monte carlo simulation with new inputs for each "experiment"?

It shouldn't be likely that disk IO is a limitation, unless each experiment depends on the results of the previous experiment and the simulation has to write then read the result to disk each time (if it does, fire your programmer).

That means disk IO isn't likely to be a limiting factor and you'd best be served by spending your money on the processor. The questions you can't/didn't answer aren't likely to change that. The computer you posted would likely be good for what you are doing, but I don't know if you could get something comparable for cheaper (the one I described in my first post would likely be several hundred cheaper).

Neuge 11-20-2007 03:01 AM

Re: I need a serious workhorse computer for complex simulations
 
I will add this. Given the computational parameters in your original post, it seems to me that a dual quad-core system would be overkill. You could probably get by with something smaller for much less.

That's just semi-informed personal opinion though. I can't provide any evidence to back that up.

Bremen 11-20-2007 03:16 AM

Re: I need a serious workhorse computer for complex simulations
 
If you can talk to the programmer why not just ask him what would be best?

Ganjasaurus Rex 11-20-2007 03:47 AM

Re: I need a serious workhorse computer for complex simulations
 
[ QUOTE ]
[ QUOTE ]
You're absolutely right, in that i don't know what i need. The more i think about it, the more i realize that i'm lost and need more guidance before purchasing the right computer.

I'll try to answer your questions.

The simulation is mimicking 200,000 typical statistical "experiments" (well, each permutation is). To be specific, i believe that the statistic P-replication (P-rep) underestimates the true probability of replication. Thus, i've created 200,000 "experiments" using various population parameters (permutations of effect sizes) to determine what the actual probability of replication is, and then compare the mean/median of those to what P-rep predicts. The experiments are basically t-tests with an n = 10, 20, 40, and 100. They are all running simultaneously in the program. The program is written in C++. I didn't write (my programmer did), but i do have access to the source code if necessary.

Sorry, i don't know what "parallelization (eg. MPI, OpenMP)" means.

Thanks for your help in this. I do appreciate it.

[/ QUOTE ]
Okay, first let me see if I understand this. You're running a monte carlo simulation with new inputs for each "experiment"?

It shouldn't be likely that disk IO is a limitation, unless each experiment depends on the results of the previous experiment and the simulation has to write then read the result to disk each time (if it does, fire your programmer).

That means disk IO isn't likely to be a limiting factor and you'd best be served by spending your money on the processor. The questions you can't/didn't answer aren't likely to change that. The computer you posted would likely be good for what you are doing, but I don't know if you could get something comparable for cheaper (the one I described in my first post would likely be several hundred cheaper).

[/ QUOTE ]
Yes, there are new inputs for each experiment. None of the experiments depend on prior experimental results. The only thing that relies on prior experimental results in the final tally, which comes after all the experiments have run.

[ QUOTE ]
That means disk IO isn't likely to be a limiting factor and you'd best be served by spending your money on the processor. The questions you can't/didn't answer aren't likely to change that. The computer you posted would likely be good for what you are doing, but I don't know if you could get something comparable for cheaper (the one I described in my first post would likely be several hundred cheaper).

[/ QUOTE ]
Thank you for your advice. I very much appreciate it.

Ganjasaurus Rex 11-20-2007 03:53 AM

Re: I need a serious workhorse computer for complex simulations
 
[ QUOTE ]
If you can talk to the programmer why not just ask him what would be best?

[/ QUOTE ]
He doesn't know anything about hardware. He didn't even know how to hook up a bluetooth printer adapter. [img]/images/graemlins/frown.gif[/img] But, on the bright side, he's supposed to be the best grad student in the CS dept when it comes to programming C++ and Java. Go figure.


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