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Re: Generate Same Sequence of Random Numbers in IDL and C [message #89071 is a reply to message #89063]

Tue, 22 July 2014 09:21

sweiss1993
Messages: 4
Registered: July 2014

Junior Member

Hi Mike,

Thanks for the reply! I seeded the way you described, and there is still a difference in the random number output for each program. To be specific, I seeded both with a constant integer of 4357 (default seed for GSL's RNG). I also made sure the seed was not reinitialized with every loop iteration. Both programs now have a constant output every time the program runs. However, the outputs from the programs do not match each other. On closer inspection, I noticed that the first random numbers match, but after the next iteration, they are not the same.

Since both programs use the same number generator and start with the same seed, I am guessing there must be a difference in how GDL changes the seed with each call. So, do you or anyone happen to know how exactly IDL/GDL changes the seed for a constant seed input? I have read the documentation, and attempted to read the GDL C++ source code, but neither have been much help in this regard.

- Sam

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[Message index]

		Generate Same Sequence of Random Numbers in IDL and C By: sweiss1993 on Mon, 21 July 2014 09:11
		Re: Generate Same Sequence of Random Numbers in IDL and C By: Michael Galloy on Mon, 21 July 2014 10:16
		Re: Generate Same Sequence of Random Numbers in IDL and C By: sweiss1993 on Tue, 22 July 2014 09:21
		Re: Generate Same Sequence of Random Numbers in IDL and C By: Michael Galloy on Tue, 22 July 2014 11:07
		Re: Generate Same Sequence of Random Numbers in IDL and C By: Michael Galloy on Tue, 22 July 2014 14:13
		Re: Generate Same Sequence of Random Numbers in IDL and C By: sweiss1993 on Wed, 23 July 2014 09:52
		Re: Generate Same Sequence of Random Numbers in IDL and C By: Michael Galloy on Wed, 23 July 2014 11:03
		Re: Generate Same Sequence of Random Numbers in IDL and C By: sweiss1993 on Wed, 23 July 2014 16:42
		Re: Generate Same Sequence of Random Numbers in IDL and C By: Michael Galloy on Thu, 24 July 2014 10:34

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