cino hilliard on Tue, 04 Oct 2005 04:53:09 +0200

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Pari on P3 vs P4 binary windows distro

GP/PARI CALCULATOR Version 2.2.10 (development CHANGES-1.1200)
      i686 running cygwin (ix86 kernel) 32-bit version
     compiled: Apr 21 2005, gcc-3.4.1 (cygming special)
      (readline v5.0 enabled, extended help available)

I have been running a script to store prime numbers

primes4(n,m) = \\save pseudoprimes from 100 bill to 200 bill but omit first number \\This will allow merging with the ztest2-100.txt 11 byte record file \\An if statement when prime(n) > 100e9 we will add xe12 where x = 1,2,3..
           fil = concat("c:/sieve/ztest",n);
           fil = concat(fil,"-");
           fil = concat(fil,m);
           fil = concat(fil,".txt");
           str = mid(Str(1e12+j),3,11);
\\          print(str);
This allowes me to extend the Pari prime(x) function greatly with a prime2(x) that reads a
45 gig and 10 gig (up to now) file.

The problem

Just a week or so ago I noticed that my P3 1 ghz 256 meg ram runs about 4 times faster than my p4 2.53 ghz 2 gig ram. I have reinstalled cygwin from the website and still my p4 writes about 300,000 bytes while my p3 writes 1,100,000. The p3 will do blocks of 5 billion
in about 30 hours.

A simple fprintf program shows my p4 writes 20-30% faster.

So I wrote this test script

testwrite(n) =
\\              system("c:/pari/gpfiles/deltestwrite");

The p3 does 10,000 writes in about 3 sec while the p4 takes 25.
Also the gettime() does not show the correct time on disk writes.
Neither does ## at the prompt.

The real kicker in fooling around with this I can't get pari running properly on my p4. I lost the delete key now it gives me ~. My p3 still does this. Also I lost the system command
on the p4.

It is off topic but I lost gcc 3.4.4 compiling on both systems like it does not recignize the path properle. Executables previously compiled still work but I can't the thin to compile.

My guess is this problem is with cygwin.

Any help on the pari situation is appreciated is appreciated.