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Offline mkraska  
#1 Posted : 19 August 2013 19:16:38(UTC)
mkraska


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Perhaps not a bug, but a problem. The importdata(9) function has a quadratic dependence of time consumption versus datasets read. For large files this becomes prohibitive. Pre-allocation of the matrix does not help.

If you read the file piecewise into separate matrices, then the time consumption is
linear. However, combining them using stack() turns out to be even more ineffective. Other operations like column extraction or plotting augmented columns fast in comparison to read operation. Therefore, an efficient text file reading routine would be highly welcome.

If you want to try the example, put data and .sm file in the same directory and launch the .sm file there.

Edited by user 23 March 2014 14:02:12(UTC)  | Reason: Not specified

File Attachment(s):
B14 Scherung.txt (581kb) downloaded 42 time(s).
Readtest.sm (16kb) downloaded 43 time(s).
mkraska attached the following image(s):
readtest.PNG
Martin Kraska

Pre-configured portable distribution of SMath Studio: https://en.smath.info/wi...th%20with%20Plugins.ashx
thanks 1 user thanked mkraska for this useful post.
on 19/08/2013(UTC)
Offline mkraska  
#2 Posted : 08 September 2013 13:17:20(UTC)
mkraska


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Problem solved. The quadratic time dependence holds for optimization> symbolic. For optimization> numeric, the time dependence is approximately linear.

Edited by user 08 September 2013 15:53:02(UTC)  | Reason: Not specified

File Attachment(s):
DataExchange.zip (382kb) downloaded 40 time(s).
mkraska attached the following image(s):
importdata.PNG
Martin Kraska

Pre-configured portable distribution of SMath Studio: https://en.smath.info/wi...th%20with%20Plugins.ashx
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