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Re: chunk indexing like [message #69306 is a reply to message #69303]

Sun, 10 January 2010 05:52

Wout De Nolf
Messages: 194
Registered: October 2008

Senior Member

On Sat, 9 Jan 2010 01:37:18 -0800 (PST), chris <rogass@googlemail.com>
wrote:

> h=histogram(total(n>0,/CUMULATIVE,/int)-1,/
> BINSIZE,MIN=0,REVERSE_INDICES=ri )
> nh=n_elements(h)
> chinkind=ri[0:nh-1]-ri[0]
> ind2=where([1,chinkind[1:*]-chinkind[0:nh-2]] ne 0)
> l1=lindgen(nh)-ind2[chinkind]

The code below solves the histogram approach error but even when
excluding the histogram from timing (I need chunk indexing anyway),
the loop approach is the fastest.

h=histogram(total(n>0,/CUMULATIVE,/int)-1,/BINSIZE,MIN=0,REVERSE_INDICES=ri)
nh=n_elements(h)
chunkind=ri[0:nh-1]-ri[0]

t0=systime(1)
tmp=[1,chunkind[1:*]-chunkind[0:nh-2]]
ind2=where(tmp ne 0)
tmp=total((tmp-1)>0,/cum,/int)
l2=lindgen(nh)-ind2[chunkind-tmp]
print,'Histogram-approach: ',systime(1)-t0,' seconds for
,',n_elements(n), ' elements'

Timing:
CR-Rebin/mod-approach: 1.4690001 seconds for , 10000 elements
Histogram-approach: 2.3290000 seconds for , 10000 elements
Loop-approach: 0.82800007 seconds for , 10000 elements

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[Message index]

		Re: chunk indexing like By: David Fanning on Sun, 10 January 2010 08:09
		Re: chunk indexing like By: Wout De Nolf on Sun, 10 January 2010 08:05
		Re: chunk indexing like By: David Fanning on Sun, 10 January 2010 07:07
		Re: chunk indexing like By: Wout De Nolf on Sun, 10 January 2010 05:52
		Re: chunk indexing like By: Wout De Nolf on Sun, 10 January 2010 05:09
		Re: chunk indexing like By: Wout De Nolf on Sun, 10 January 2010 04:22
		Re: chunk indexing like By: rogass on Sat, 09 January 2010 11:07
		Re: chunk indexing like By: David Fanning on Sat, 09 January 2010 09:53
		Re: chunk indexing like By: rogass on Sat, 09 January 2010 08:50
		Re: chunk indexing like By: David Fanning on Sat, 09 January 2010 07:10
		Re: chunk indexing like By: rogass on Sat, 09 January 2010 02:15
		Re: chunk indexing like By: rogass on Sat, 09 January 2010 01:37
		Re: chunk indexing like By: pgrigis on Fri, 08 January 2010 08:16
		Re: chunk indexing like By: Wout De Nolf on Fri, 08 January 2010 06:12

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