I recently did a clean install of Fedora 9 (formerly running Fedora 8)
and then
installed sage-3.0.3 from source (formerly running sage-3.0). After
running
"sage -testall" I ran a couple of my own programs.
I was surprised to see one of the programs (sieve of Erasthenes) run
70% longer.
I installed sage-3.0 from source and verified that sage-3.0.3 was
indeed taking
70% longer to run the sieve program than sage-3.0 did.
To narrow down the problem, I installed sage-3.0.1 and sage-3.0.2,
both from
source. I then determined the performance problem was introduced
going from
sage-3.0.1 to sage-3.0.2.
The following doc shows my system; output from the sieve progam under
sage-3.0, sage-3.0.1, sage-3.0.2, and sage-3.0.3; and source for the
sieve
program.
The system has a single user, no load, no swapping, and the
performance monitor
indicates that the CPU (2.8 GHz P4) is pegged during the entire
elapsed time.
uname -a
Linux DH04.HAMMOND 2.6.25-14.fc9.i686 #1 SMP Thu May 1 06:28:41 EDT
2008 i686 i686 i386 GNU/Linux
/home/daryl/sage-3.0/sage /home/daryl/UserData/sage/sieve.sage
============================================
SAGE Version 3.0, Release Date: 2008-04-23
Start time: Wed Jul 2 17:17:52 2008
array size: 10000000
number of primes: 664580
End time: Wed Jul 2 17:19:03 2008
Elapsed seconds: 70.93
============================================
/home/daryl/sage-3.0.1/sage /home/daryl/UserData/sage/sieve.sage
============================================
SAGE Version 3.0.1, Release Date: 2008-05-05
Start time: Wed Jul 2 17:19:18 2008
array size: 10000000
number of primes: 664580
End time: Wed Jul 2 17:20:30 2008
Elapsed seconds: 72.58
============================================
/home/daryl/sage-3.0.2/sage /home/daryl/UserData/sage/sieve.sage
============================================
SAGE Version 3.0.2, Release Date: 2008-05-24
Start time: Wed Jul 2 17:20:47 2008
array size: 10000000
number of primes: 664580
End time: Wed Jul 2 17:22:53 2008
Elapsed seconds: 126.51
============================================
/home/daryl/sage-3.0.3/sage /home/daryl/UserData/sage/sieve.sage
============================================
SAGE Version 3.0.3, Release Date: 2008-06-17
Start time: Wed Jul 2 17:23:09 2008
array size: 10000000
number of primes: 664580
End time: Wed Jul 2 17:25:14 2008
Elapsed seconds: 124.39
============================================
cat /home/daryl/UserData/sage/sieve.sage
#!/usr/bin/env sage
# sieve of Erasthenes
# 2008/04/29 DWH Switch from numerical array to character array for
primes;
# Switch from srange() to while loop.
#
#-------------------------------------------------------------------------------
from time import *
# print start time
print
print '============================================'
print version()
print
start = time()
print 'Start time: ', ctime(start)
print
#create prime array p of size n and initialize to '1'
n = 10 * 1000 * 1000
print 'array size: ', n
p = list()
array_ctr = -1
while array_ctr < n:
array_ctr = array_ctr + 1
p.append('1')
# initialize first two array elements to '0'
p[0] = '0'
p[1] = '0'
# assign '0' to non-prime numbers
q = 1
while q * q < n:
q = q + 1
if p[q] == '1':
z = q * q - q
while z + q < n:
z = z + q
p[z] = '0'
# count primes and print count
ctr = 0
array_ctr = -1
while array_ctr < n:
array_ctr = array_ctr + 1
if p[array_ctr] == '1':
ctr = ctr + 1
print 'number of primes:', ctr
# print end time
print
end = time()
print 'End time: ', ctime(end)
elapsed = end - start
print 'Elapsed seconds: ', round(elapsed,2)
print
print '============================================'
print
-Daryl Hammond
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