Talk:Verhoeff algorithm - Revision history

170.140.105.17: /* Error in example? */ Reply

2024-11-23T17:27:21Z

Error in example?: Reply

← Previous revision		Revision as of 17:27, 23 November 2024
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	In the Description, it says 'the check digit for 248 is 5'. However, this does not seem to be consistent with the definition of f and the verification given in the same section. If the number is instead 249 everything else seems to agree (also supported by https://kik.amc.nl/home/rcornet/verhoeff.html ); should it be 'the check digit for 249 is 5'? [[Special:Contributions/62.63.252.68\|62.63.252.68]] ([[User talk:62.63.252.68\|talk]]) 21:49, 28 October 2024 (UTC)		In the Description, it says 'the check digit for 248 is 5'. However, this does not seem to be consistent with the definition of f and the verification given in the same section. If the number is instead 249 everything else seems to agree (also supported by https://kik.amc.nl/home/rcornet/verhoeff.html ); should it be 'the check digit for 249 is 5'? [[Special:Contributions/62.63.252.68\|62.63.252.68]] ([[User talk:62.63.252.68\|talk]]) 21:49, 28 October 2024 (UTC)

			:It is most definitely incorrect! It must be fixed! Source: I did it by hand four times and thought I was going mad. [[Special:Contributions/170.140.105.17\|170.140.105.17]] ([[User talk:170.140.105.17\|talk]]) 17:27, 23 November 2024 (UTC)

62.63.252.68: /* Error in example? */ new section

2024-10-28T21:49:52Z

Error in example?: new section

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	Not sure 236 is a great example because 236 is ALSO a Verhoeff number. [[Special:Contributions/150.143.239.141\|150.143.239.141]] ([[User talk:150.143.239.141\|talk]]) 14:07, 9 April 2024 (UTC)		Not sure 236 is a great example because 236 is ALSO a Verhoeff number. [[Special:Contributions/150.143.239.141\|150.143.239.141]] ([[User talk:150.143.239.141\|talk]]) 14:07, 9 April 2024 (UTC)

			== Error in example? ==

			In the Description, it says 'the check digit for 248 is 5'. However, this does not seem to be consistent with the definition of f and the verification given in the same section. If the number is instead 249 everything else seems to agree (also supported by https://kik.amc.nl/home/rcornet/verhoeff.html ); should it be 'the check digit for 249 is 5'? [[Special:Contributions/62.63.252.68\|62.63.252.68]] ([[User talk:62.63.252.68\|talk]]) 21:49, 28 October 2024 (UTC)

150.143.239.141: /* Better Example? */ new section

2024-04-09T14:07:11Z

Better Example?: new section

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	This article is incomplete please add the complete algorithm either in pseudocode or the steps list. <!-- Template:Unsigned IP --><small class="autosigned">— Preceding [[Wikipedia:Signatures\|unsigned]] comment added by [[Special:Contributions/2806:106E:B:AEBA:26EB:3B05:6D18:7C96\|2806:106E:B:AEBA:26EB:3B05:6D18:7C96]] ([[User talk:2806:106E:B:AEBA:26EB:3B05:6D18:7C96#top\|talk]]) 23:05, 3 December 2023 (UTC)</small> <!--Autosigned by SineBot-->		This article is incomplete please add the complete algorithm either in pseudocode or the steps list. <!-- Template:Unsigned IP --><small class="autosigned">— Preceding [[Wikipedia:Signatures\|unsigned]] comment added by [[Special:Contributions/2806:106E:B:AEBA:26EB:3B05:6D18:7C96\|2806:106E:B:AEBA:26EB:3B05:6D18:7C96]] ([[User talk:2806:106E:B:AEBA:26EB:3B05:6D18:7C96#top\|talk]]) 23:05, 3 December 2023 (UTC)</small> <!--Autosigned by SineBot-->

			== Better Example? ==

			Not sure 236 is a great example because 236 is ALSO a Verhoeff number. [[Special:Contributions/150.143.239.141\|150.143.239.141]] ([[User talk:150.143.239.141\|talk]]) 14:07, 9 April 2024 (UTC)

Cewbot: Maintain {{WPBS}}: 2 WikiProject templates. Remove 1 deprecated parameter: field.

2024-03-09T05:58:25Z

Maintain {{WPBS}}: 2 WikiProject templates. Remove 1 deprecated parameter: field.

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Qwerfjkl (bot): Implementing WP:PIQA (Task 26)

2024-02-07T08:49:46Z

Implementing WP:PIQA (Task 26)

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	{{maths rating\|class=C\|priority=Low\|field=algebra}}
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			{{WikiProject Computing\|auto=inherit}}

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	= Is this algorithm correct? =		= Is this algorithm correct? =

SineBot: Signing comment by 2806:106E:B:AEBA:26EB:3B05:6D18:7C96 - "/* This article is incomplete */ new section"

2023-12-03T23:06:37Z

Signing comment by 2806:106E:B:AEBA:26EB:3B05:6D18:7C96 - "This article is incomplete: new section"

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	== This article is incomplete ==		== This article is incomplete ==

	This article is incomplete please add the complete algorithm either in pseudocode or the steps list.		This article is incomplete please add the complete algorithm either in pseudocode or the steps list. <!-- Template:Unsigned IP --><small class="autosigned">— Preceding [[Wikipedia:Signatures\|unsigned]] comment added by [[Special:Contributions/2806:106E:B:AEBA:26EB:3B05:6D18:7C96\|2806:106E:B:AEBA:26EB:3B05:6D18:7C96]] ([[User talk:2806:106E:B:AEBA:26EB:3B05:6D18:7C96#top\|talk]]) 23:05, 3 December 2023 (UTC)</small> <!--Autosigned by SineBot-->

2806:106E:B:AEBA:26EB:3B05:6D18:7C96: /* This article is incomplete */ new section

2023-12-03T23:05:34Z

This article is incomplete: new section

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	:In general you might also care to do user validation of input as early as possible, and you might care to give different error messages when you a) see the user has made a typo, or b) there actually isn't such a record. In practice, for example, you might check the checksum in javascript on a web input page before sending the form to a server. Also, in practice there's not very much difference in the difficulty of implementing any of the checksum algorithms, nor their computational complexity. Hope that's of some use. [[Special:Contributions/217.155.120.113\|217.155.120.113]] ([[User talk:217.155.120.113\|talk]]) 20:11, 23 March 2014 (UTC)		:In general you might also care to do user validation of input as early as possible, and you might care to give different error messages when you a) see the user has made a typo, or b) there actually isn't such a record. In practice, for example, you might check the checksum in javascript on a web input page before sending the form to a server. Also, in practice there's not very much difference in the difficulty of implementing any of the checksum algorithms, nor their computational complexity. Hope that's of some use. [[Special:Contributions/217.155.120.113\|217.155.120.113]] ([[User talk:217.155.120.113\|talk]]) 20:11, 23 March 2014 (UTC)

			== This article is incomplete ==

			This article is incomplete please add the complete algorithm either in pseudocode or the steps list.

2806:106E:B:AEBA:26EB:3B05:6D18:7C96 at 23:01, 3 December 2023

2023-12-03T23:01:17Z

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	Is this algorithm correct?		= Is this algorithm correct? =

	According to [http://www.academic.marist.edu/mwa/vcdc.htm], 3170092 is also a valid number.		According to [http://www.academic.marist.edu/mwa/vcdc.htm], 3170092 is also a valid number.

BU RoBOT: /* top */Auto-assessment of article class. Editors are encouraged to manually assess articles. See User:BU_RoBOT/autoassess for more info.

2016-06-23T15:32:09Z

top: Auto-assessment of article class. Editors are encouraged to manually assess articles. See User:BU_RoBOT/autoassess for more info.

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217.155.120.113: Answered some old questions

2014-03-23T20:11:21Z

Answered some old questions

← Previous revision		Revision as of 20:11, 23 March 2014
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	:: 3170092 is given as an example of valid number in Kirtland, Joseph (2001): ''Identification Numbers and Check Digit Schemes'' (see the exact reference in the article).		:: 3170092 is given as an example of valid number in Kirtland, Joseph (2001): ''Identification Numbers and Check Digit Schemes'' (see the exact reference in the article).
	:: From a quick superficial reading, it looks like Kirtland and the Wikipedia article actually use 2 different variants of the Verhoeff algorithm, so no wonder a number accepted by Kirtland is refused by Wikipedia. The difference lies in table p: while the Wikipedia article uses powers of permutation (1 5 8 9 4 2 7 0)(3 6), Kirtland uses powers of (0) (1 4) (2 3) (5 6 7 8 9). (Also, they might apply the powers in a different direction to the original digits: right-to-left for Kirtland, left-to-right for Wikipedia, I haven't checked.) The algorithm in the Wikipedia article seems to be the one in use by the [[German Bundesbank]] between 1990 and (2002?) for their banknote serial numbers. (Actually, Kirtland also does mention the German Bundesbank and its permutation, in a final short note.) [[User:FvdP\|--FvdP]] ([[User talk:FvdP\|talk]]) 20:50, 20 August 2012 (UTC)		:: From a quick superficial reading, it looks like Kirtland and the Wikipedia article actually use 2 different variants of the Verhoeff algorithm, so no wonder a number accepted by Kirtland is refused by Wikipedia. The difference lies in table p: while the Wikipedia article uses powers of permutation (1 5 8 9 4 2 7 0)(3 6), Kirtland uses powers of (0) (1 4) (2 3) (5 6 7 8 9). (Also, they might apply the powers in a different direction to the original digits: right-to-left for Kirtland, left-to-right for Wikipedia, I haven't checked.) The algorithm in the Wikipedia article seems to be the one in use by the [[German Bundesbank]] between 1990 and (2002?) for their banknote serial numbers. (Actually, Kirtland also does mention the German Bundesbank and its permutation, in a final short note.) [[User:FvdP\|--FvdP]] ([[User talk:FvdP\|talk]]) 20:50, 20 August 2012 (UTC)

			:::Even more years later ... I can confirm Verhoeff evaluations a great number of different permutations, and I added that to the main article with reference to this particular permutation (1 5 8 9 4 2 7 0)(3 6). The original paper has sophisticated measurements for different permutations. According to my understanding, 317009'''9''' is correct for the 'canonical' permutation as given in the Wiki article and all of the implementations I've seen (from the links on main article). The Marist College page ([https://web.archive.org/web/20080315070303/http://www.academic.marist.edu/mwa/vcdc.htm\|archive]) uses a different permutation, as noted by FvpP above, which will give you a different answer. I'm afraid I don't have access to the Kirtland book to see what he says there. [[Special:Contributions/217.155.120.113\|217.155.120.113]] ([[User talk:217.155.120.113\|talk]]) 20:11, 23 March 2014 (UTC)

	I don't understand the following description:		I don't understand the following description:
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	:I added some explanation which I hope will take care of this issue. The point is that if all a client application needs to be told is that a given ID is not found in the system, there is no need for the client app to do the check-digit calculations itself; it will simply do a lookup using the malformed ID, and it won't match anything. However, if it is decided that a client application needs to be able to explicitly say that a given ID has failed the check-digit test and must have been garbled somehow, then the client would naturally need to have the necessary smarts to do the check-digit calculations on the ID before trying to do a lookup. [[User:Richwales\|Richwales]] ([[User talk:Richwales\|talk]]) 19:55, 7 March 2008 (UTC)		:I added some explanation which I hope will take care of this issue. The point is that if all a client application needs to be told is that a given ID is not found in the system, there is no need for the client app to do the check-digit calculations itself; it will simply do a lookup using the malformed ID, and it won't match anything. However, if it is decided that a client application needs to be able to explicitly say that a given ID has failed the check-digit test and must have been garbled somehow, then the client would naturally need to have the necessary smarts to do the check-digit calculations on the ID before trying to do a lookup. [[User:Richwales\|Richwales]] ([[User talk:Richwales\|talk]]) 19:55, 7 March 2008 (UTC)

			:In general you might also care to do user validation of input as early as possible, and you might care to give different error messages when you a) see the user has made a typo, or b) there actually isn't such a record. In practice, for example, you might check the checksum in javascript on a web input page before sending the form to a server. Also, in practice there's not very much difference in the difficulty of implementing any of the checksum algorithms, nor their computational complexity. Hope that's of some use. [[Special:Contributions/217.155.120.113\|217.155.120.113]] ([[User talk:217.155.120.113\|talk]]) 20:11, 23 March 2014 (UTC)