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[gnuastro-devel] [bug #56754] Sigma clipping output value not reasonable
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From: |
Raul Infante-Sainz |
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Subject: |
[gnuastro-devel] [bug #56754] Sigma clipping output value not reasonable |
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Date: |
Tue, 13 Aug 2019 05:55:54 -0400 (EDT) |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36 |
URL:
<https://savannah.gnu.org/bugs/?56754>
Summary: Sigma clipping output value not reasonable
Project: GNU Astronomy Utilities
Submitted by: infantesainz
Submitted on: Tue 13 Aug 2019 09:55:52 AM UTC
Category: Statistics
Severity: 3 - Normal
Item Group: Output not reasonable
Status: None
Privacy: Public
Assigned to: None
Open/Closed: Open
Discussion Lock: Any
_______________________________________________________
Details:
I found a no reasonable result when trying to obtain the sigma clipping values
of a distribution (attached as `data.txt' file).
The command I run using gnuastro most recent version (0.10.5-4079) is:
aststatistics data.txt --column=1 --sigmaclip --sclipparams=3,0.2
Obtaining:
Statistics
-------
Input: data.txt
Column: 1
-------
3-sigma clipping steps until relative change in STD is less than 0.2:
round number median mean STD
1 200 1568 1567.76 1.94484
2 197 1568 1568 0
3 197 1568 1568 0
4 197 1568 1568 0
5 197 1568 1568 0
6 197 1568 1568 0
7 197 1568 1568 0
8 197 1568 1568 0
9 197 1568 1568 0
10 197 1568 1568 0
11 197 1568 1568 0
12 197 1568 1568 0
13 197 1568 1568 0
14 197 1568 1568 0
15 197 1568 1568 0
16 197 1568 1568 0
17 197 1568 1568 0
18 197 1568 1568 0
19 197 1568 1568 0
20 197 1568 1568 0
21 197 1568 1568 0
22 197 1568 1568 0
23 197 1568 1568 0
24 197 1568 1568 0
25 197 1568 1568 0
26 197 1568 1568 0
27 197 1568 1568 0
28 197 1568 1568 0
29 197 1568 1568 0
30 197 1568 1568 0
31 197 1568 1568 0
32 197 1568 1568 0
33 197 1568 1568 0
34 197 1568 1568 0
35 197 1568 1568 0
36 197 1568 1568 0
37 197 1568 1568 0
38 197 1568 1568 0
39 197 1568 1568 0
40 197 1568 1568 0
41 197 1568 1568 0
42 197 1568 1568 0
43 197 1568 1568 0
44 197 1568 1568 0
45 197 1568 1568 0
46 197 1568 1568 0
47 197 1568 1568 0
48 197 1568 1568 0
49 197 1568 1568 0
50 197 1568 1568 0
-------
Summary:
Number of input elements: 200
Number of clips: 50
Final number of elements: nan
Median: nan
Mean: nan
Standard deviation: nan
This is completely unreasonable since from the first iteration the result is
correct, but at the end it says nan!!
If I set the number of maximum iteration to 3 (for example) the result is
correct, that is:
aststatistics data.txt --column=1 --sigmaclip --sclipparams=3,3
Gives:
Statistics
-------
Input: data.txt
Column: 1
-------
3-sigma clipping steps for 3 clips:
round number median mean STD
1 200 1568 1567.76 1.94484
2 197 1568 1568 0
3 197 1568 1568 0
-------
Summary:
Number of input elements: 200
Final number of elements: 197
Median: 1568
Mean: 1568
Standard deviation: 0
_______________________________________________________
File Attachments:
-------------------------------------------------------
Date: Tue 13 Aug 2019 09:55:52 AM UTC Name: data.txt Size: 1000B By:
infantesainz
<http://savannah.gnu.org/bugs/download.php?file_id=47343>
_______________________________________________________
Reply to this item at:
<https://savannah.gnu.org/bugs/?56754>
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- [gnuastro-devel] [bug #56754] Sigma clipping output value not reasonable,
Raul Infante-Sainz <=