| Re: Can I do this without using loops? [message #6403 is a reply to message #6323] |
Sun, 16 June 1996 00:00   |
steinhh
Messages: 260
Registered: June 1994
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Senior Member |
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Here are some timing results for an Alphaserver 2100 with 4 CPUs
installed and about 1 GB internal memory (which means that the
large test didn't swap, I think. However, the .SIZE command in
IDL only takes unsigned integers for the number of Kilobytes
to reserve, so some tests bombed because of internal memory
limits in IDL). I made sure that only 2 other jobs were executing
concurrently, so one CPU was more or less dedicated to running
this test. (With the fourth doing housekeeping).
I'm not sure about the cache size or processor speed, though.
I added methods 10 and 11, (included at the end of the article)
to test the /sample keywords, and to try a combination of the
fast column insertion (method 8) with a transpose.
I don't have pv-wave, but just for fun I tested both Idl 3.6.1c
and Idl 4.0, and I got a surprise! Unless I've made some strange
mistakes, the comparison is quite counterintuitive.
Rows and columns: 3000 3000
IDL 3.6.1c 4.0 | 3.6.1c 4.0
1. 4.64 7.16 | 8.16 10.10
2. 6.92 7.60 | 0.71 0.74
3. 0.96 1.39 | 0.92 1.36
4. 2.25 2.90 | 2.20 2.98
5. 17.58 21.84 | 17.56 21.83
6. 32.78 38.85 | 32.22 38.94
7. 18.98 21.38 | 18.96 21.67
8. 0.73 0.75 | 3.64 3.69
9. 9.40 11.51 | 5.49 7.22
10. 0.69 0.69 | 3.65 3.70
11. 0.69 0.69 | 4.75 5.38
Rows and columns: 1000 30000
3.6.1c 4.0 | 3.6.1c 4.0
1. 15.88 24.00 | 17.98 24.87
2. 14.21 16.70 | 2.77 2.81
3. 2.97 4.52 | 3.02 4.52
4.******* ******* | ******* *******
5. 58.70 72.90 | 58.67 72.88
6. 109.13 129.85 | 107.16 129.93
7. 60.89 69.90 | 60.94 71.47
8. 2.75 2.78 | 5.35 5.71
9.******* ******* | 19.64 24.75
10. 2.71 2.72 | 5.42 5.48
11. 2.70 2.79 | ******* *******
Note that version 4.0 is actually *always* slower than version
3.6.1c. Is the "upgrade" to 4.0 coincident with the switch
from fortran to C source code? In that case, maybe RSI should
consider switching back (at least for some core routines), if
these numbers are correct.
Here are the 3.6.1c results relative to the best 3.6.1c results,
and 4.0 results relative to the corresponding 3.6.1c results:
Rows and columns: 3000 3000
3.6.1c 4.0 | 3.6.1c 4.0
1. 6.72 1.54 | 11.49 1.24
2. 10.03 1.10 | 1.00 1.04
3. 1.39 1.45 | 1.30 1.47
4. 3.26 1.29 | 3.10 1.35
5. 25.48 1.24 | 24.73 1.24
6. 47.51 1.19 | 45.38 1.21
7. 27.51 1.13 | 26.70 1.14
8. 1.06 1.03 | 5.13 1.01
9. 13.62 1.22 | 7.73 1.32
10. 1.00 1.00 | 5.14 1.01
11. 1.00 1.00 | 6.69 1.13
Rows and columns: 1000 30000
3.6.1c 4.0 | 3.6.1c 4.0
1. 5.88 1.50 | 6.49 1.38
2. 5.26 1.17 | 1.00 1.01
3. 1.10 1.52 | 1.09 1.50
4.******* ******* | ******* *******
5. 21.74 1.24 | 21.18 1.24
6. 40.42 1.19 | 38.69 1.21
7. 22.55 1.14 | 22.00 1.17
8. 1.02 1.01 | 1.93 1.07
9.******* ******* | 7.09 1.26
10. 1.00 1.00 | 1.95 1.01
11. 1.00 1.03 | ******* *******
For a slower alpha machine (front cover says DEC 3000) I only
bothered to time the small test. Here the differences between
version 3.6 and 4.0 are slightly less systematic.
Rows and columns: 3000 3000
IDL 3.6.1c 4.0 | 3.6.1c 4.0
1. 11.96 11.63 | 14.27 14.62
2. 7.83 9.88 | 0.85 0.88
3. 1.71 2.83 | 1.71 2.83
4. 19.18 21.98 | 20.64 17.82
5. 39.89 43.95 | 40.09 43.98
6. 81.61 98.88 | 80.17 101.32
7. 42.68 50.47 | 41.92 48.96
8. 0.92 1.43 | 3.91 3.88
9. 41.61 48.65 | 9.87 13.07
10. 0.85 0.85 | 3.92 3.85
11. 0.91 1.39 | 42.91 29.58
Relative results:
1. 14.07 0.97 | 16.79 1.02
2. 9.21 1.26 | 1.00 1.04
3. 2.01 1.65 | 2.01 1.65
4. 22.56 1.15 | 24.28 0.86
5. 46.93 1.10 | 47.16 1.10
6. 96.01 1.21 | 94.32 1.26
7. 50.21 1.18 | 49.32 1.17
8. 1.08 1.55 | 4.60 0.99
9. 48.95 1.17 | 11.61 1.32
10. 1.00 1.00 | 4.61 0.98
11. 1.07 1.53 | 50.48 0.69
For a DECstation 5000/240 I only ran an even smaller test
(1000,1000), with the following results:
Rows and columns: 1000 1000
IDL 3.6.1c 4.0 | 3.6.1c 4.0
1. 4.66 12.90 | 4.84 11.67
2. 2.60 2.80 | 0.11 0.09
3. 0.91 0.93 | 0.90 0.98
4. 1.72 1.66 | 1.22 1.25
5. 13.10 12.53 | 13.34 12.40
6. 28.32 26.28 | 21.76 25.91
7. 13.82 12.93 | 13.98 12.93
8. 0.40 0.33 | 0.70 0.71
9. 4.02 4.07 | 3.11 3.11
10. 0.19 0.24 | 0.58 0.66
11. 0.32 0.33 | 1.11 1.12
3.6.1c results relative to the best 3.6.1c results,
and 4.0 results relative to the corresponding 3.6.1c results:
1. 24.53 2.77 | 44.00 2.41
2. 13.68 1.08 | 1.00 0.82
3. 4.79 1.02 | 8.18 1.09
4. 9.05 0.97 | 11.09 1.02
5. 68.95 0.96 | 121.27 0.93
6. 149.05 0.93 | 197.82 1.19
7. 72.74 0.94 | 127.09 0.92
8. 2.11 0.83 | 6.36 1.01
9. 21.16 1.01 | 28.27 1.00
10. 1.00 1.26 | 5.27 1.14
11. 1.68 1.03 | 10.09 1.01
In other words, even less systematic differences. I'm still a bit
surprised that *any* of these numbers go the "wrong" way.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
PRO TEST10,rows,columns
strt = systime(1)
;
array = rebin(FINDGEN(1, columns), rows, columns,/sample)
;
time = systime(1)-strt
PRINT, 'elapsed time: ',time
RETURN
;
END
;; Identical to number 8 (just filling in for completeness)
;; The row version uses this plus a transpose
PRO test11,rows,columns
strt = systime(1)
;
array = rebin(FINDGEN(1, columns), rows, columns)
;
time = systime(1)-strt
PRINT, 'elapsed time: ',time
RETURN
END
PRO test10_rows,rows,columns
strt = systime(1)
;
array = rebin(FINDGEN(rows,1), rows, columns,/sample)
;
time = systime(1)-strt
PRINT, 'elapsed time: ',time
RETURN
;
END
PRO test11_rows,rows,columns
strt = systime(1)
;
array = TRANSPOSE(rebin(FINDGEN(1,rows), columns, rows,/sample))
;
time = systime(1)-strt
PRINT, 'elapsed time: ',time
RETURN
;
END
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