[IronPython] Multidimensional array performance on IP Beta 9

[Dino Viehland]

Definitely not expected, I've opened CodePlex bug 930 to track it (http://www.codeplex.com/WorkItem/View.aspx?ProjectName=IronPython&WorkItemId=930).  Thanks for reporting this.

From: users-bounces at lists.ironpython.com [mailto:users-bounces at lists.ironpython.com] On Behalf Of Milman, Seth
Sent: Thursday, July 13, 2006 1:31 PM
To: Discussion of IronPython
Subject: [IronPython] Multidimensional array performance on IP Beta 9

I've noticed a rather large degradation in speed when accessing elements in multidimensional arrays in the new beta 9.  Is this performance expected?

I've pasted a script below that demonstrates the issue.

Beta 8 output from the script:
1 dimensional copy: 0.4303053 seconds
2 dimensional copy: 1.1508165 seconds

Beta 9 output from the script:
            1 dimensional copy: 0.4603266 seconds
2 dimensional copy: 7.5953889 seconds

Beta 9 takes 6.6 times longer to access all the elements in the 2d array.

Is this change expected?

-Seth


# ###############################################
import System
from System import *


arraySize = 50000

a1 = Array.CreateInstance( Double, arraySize )
a2 = Array.CreateInstance( Double, arraySize )
a3 = Array.CreateInstance( Double, 2, arraySize )


ticks1 = DateTime.Now.Ticks

for j in range(2):
            for i in range(len(a1)):
                        a2[i] = a1[i]

ticks2 = DateTime.Now.Ticks

for j in range(2):
            for i in range(len(a1)):
                        a3[j,i] = a1[i]

ticks3 = DateTime.Now.Ticks

time1 = TimeSpan( ticks2 - ticks1 )
time2 = TimeSpan( ticks3 - ticks2 )

print
print '1 dimensional copy: ' + str(time1.TotalSeconds) + ' seconds'
print '2 dimensional copy: ' + str(time2.TotalSeconds) + ' seconds'
print

# ###############################################################

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