funsec mailing list archives
Re: simple question
From: "Tomas L. Byrnes" <tomb () byrneit net>
Date: Sun, 6 Dec 2009 20:46:24 -0800
I used unconverted assignments on Digital Research f77 under CCP/M 3.1d on iAPx 286 chipsets with regularity, and effect, in the early '80s. And after that, I was thankful to never use Fortran again. The bigger point is that the code is garbage, the data not much better (at least according to the comments, because we can't see the data), and the researchers have clearly been actively hiding the facts from public view. It's high time for the Open Source and Free Software ethos to dominate something on which so much of the future of mankind rests. I, for one, donated lots of CPU time to the BBC climate modeling BOINC project. I think the idea that there isn't enough computing, never mind brain, power out there to do this right is complete bunk. Let the science produce the result it will, whatever that may be, but let it at least be proper science, with the best current practices in all relevant fields being applied. Then, after the climate models are as near to unimpeachable as can be (and models can do pretty well, as the auto makers have shown), we can have the debate about the costs of various courses of action relative to their benefits and risks. Until we have a model that would pass muster for simulating the Coefficient of Drag of an automobile (and as far as I can see the CRU climate model doesn't), how can we base any major public policy decisions on it? From: Martin Tomasek [mailto:tomasek () ufe cz] Sent: Sunday, December 06, 2009 4:55 AM To: Tomas L. Byrnes Cc: FunSec [List] Subject: Re: [funsec] simple question Tomas L. Byrnes napsal(a): Yes, and it you look at the real to integer, and integer to real, assignments without conversion functions, you can see where the actual assignment may be indeterminate. I don't have the datasets, and haven't done Fortran since F77, but when I did Fortran, assignment without type conversion produced unpredictable results. Specifically, in little endian machines, assigning a real to an integer was a very workable random number generator. I learned fortran a few years ago, because I needed to test something on an astronomical library. I used g77 and never met this issue. HARRY's docs mention following compilers: compaq f90, portland group pgf90, g77, gfortran. And BTW it's depressing to read READMEs. That guy suffered when he tried to work with old fortran code and datasets.. He had to reverse-engineer undocumented binary formats, handle nearly-duplicate entries, found out that someone fixed documented error in the data - but kept same timestamp on the file. He had to handle weird scaling of coordinates, obscure measurement units etc.. Search for 'cries' and for '% x10'. From: Martin Tomasek [mailto:tomasek () ufe cz] Sent: Saturday, December 05, 2009 4:04 PM To: Tomas L. Byrnes Cc: Drsolly; funsec; RandallM Subject: Re: [funsec] simple question Tomas L. Byrnes napsal(a): Hence we return you to my focus: the code. Code does not lie, it merely does what it was told. By my reading, the CRU code produces ever more excited random numbers. Someone else please read it and prove me wrong. Quote from docs: "Had to make some changes to allow for the move back to alphas (different field length from the 'wc -l' command)." If their code depends on calling external programs, it will be difficult to verify. Unless you are sure of actual output formats. :-) -- Martin Tomasek
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Current thread:
- simple question RandallM (Dec 03)
- Re: simple question Dan White (Dec 03)
- Re: simple question Drsolly (Dec 03)
- Re: simple question Martin Tomasek (Dec 04)
- Re: simple question Tomas L. Byrnes (Dec 05)
- Re: simple question RandallM (Dec 05)
- Re: simple question Martin Tomasek (Dec 05)
- Re: simple question Tomas L. Byrnes (Dec 05)
- Re: simple question Valdis . Kletnieks (Dec 05)
- Re: simple question Martin Tomasek (Dec 06)
- Re: simple question Tomas L. Byrnes (Dec 06)
- Re: simple question Dan Kaminsky (Dec 07)
- Re: simple question Martin Tomasek (Dec 04)
- Re: simple question Tomas L. Byrnes (Dec 05)