0000487: FIXED: infinite loop in k-Means when called for degenerate data

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0000487

[ALGLIB] Data analysis

minor

have not tried

2012-09-06 09:48

2012-09-25 11:18

Reporter

SergeyB

View Status

public

Assigned To

SergeyB

Priority

normal

Resolution

fixed

Status

resolved

Product Version

Summary

0000487: FIXED: infinite loop in k-Means when called for degenerate data

Description

From http://forum.alglib.net/viewtopic.php?f=2&t=611 by andreas:

I have a situation where kmeansgenerate seems to be stuck in an infinite loop (C# version of alglib 3.6.0). The parameters are as follows (copied from the debugger):

xy: {double[57, 1]}
[0, 0]: 12.244689632138986
[1, 0]: 12.244689632138982
[2, 0]: 12.244689632138986
[3, 0]: 12.244689632138982
[4, 0]: 12.244689632138986
[5, 0]: 12.244689632138986
[6, 0]: 12.244689632138986
[7, 0]: 12.244689632138986
[8, 0]: 12.244689632138986
[9, 0]: 12.244689632138986
[10, 0]: 12.244689632138989
[11, 0]: 12.244689632138984
[12, 0]: 12.244689632138986
[13, 0]: 12.244689632138986
[14, 0]: 12.244689632138989
[15, 0]: 12.244689632138986
[16, 0]: 12.244689632138986
[17, 0]: 12.244689632138986
[18, 0]: 12.244689632138986
[19, 0]: 12.244689632138989
[20, 0]: 12.244689632138972
[21, 0]: 12.244689632138986
[22, 0]: 12.244689632138986
[23, 0]: 12.244689632138986
[24, 0]: 12.244689632138984
[25, 0]: 12.244689632138982
[26, 0]: 12.244689632138986
[27, 0]: 12.244689632138986
[28, 0]: 12.244689632138986
[29, 0]: 12.244689632138986
[30, 0]: 12.244689632138986
[31, 0]: 12.244689632138986
[32, 0]: 12.244689632138986
[33, 0]: 12.244689632138986
[34, 0]: 12.244689632138986
[35, 0]: 12.244689632138982
[36, 0]: 12.244689632138989
[37, 0]: 12.244689632138986
[38, 0]: 12.244689632138986
[39, 0]: 12.244689632138986
[40, 0]: 12.244689632138986
[41, 0]: 12.244689632138986
[42, 0]: 12.244689632138986
[43, 0]: 12.244689632138986
[44, 0]: 12.244689632138986
[45, 0]: 12.244689632138986
[46, 0]: 12.244689632138986
[47, 0]: 12.244689632138986
[48, 0]: 12.244689632138986
[49, 0]: 12.244689632138986
[50, 0]: 12.244689632138984
[51, 0]: 12.244689632138986
[52, 0]: 12.244689632138986
[53, 0]: 12.244689632138986
[54, 0]: 12.244689632138986
[55, 0]: 12.244689632138986
[56, 0]: 12.244689632138986

nPoints: 57
nVars: 1
k: 4
restarts: 1

Can you reproduce this situation?

I understand that this doesn't really constitute "good data", but unfortunately, I don't have a lot of control on the input values, they can be as meaningless as in this case. Currently I'm just filtering when there are less distinct values than clusters. I'm probably changing this to require some higher minimum range between the values and hope to avoid such situations.

I'm running the program in Vista 64bit and use VS2010 and .Net 4.

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Unspecified

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Issue History
Date Modified	Username	Field	Change
2012-09-06 09:48	SergeyB	New Issue
2012-09-06 09:48	SergeyB	Status	new => assigned
2012-09-06 09:48	SergeyB	Assigned To	=> SergeyB
2012-09-06 09:48	SergeyB	Programming language	=> Unspecified
2012-09-25 11:17	SergeyB	Status	assigned => resolved
2012-09-25 11:17	SergeyB	Fixed in Version	=> 3.7.0
2012-09-25 11:17	SergeyB	Resolution	open => fixed
2012-09-25 11:18	SergeyB	Summary	Infinite loop in k-Means when called for degenerate data => FIXED: infinite loop in k-Means when called for degenerate data

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