Talk:Square root algorithms - Revision history

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2025-05-22T00:02:10Z

Update archiving templates after a page move (Report bot issues)

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Fgnievinski: Fgnievinski moved page Talk:Methods of computing square roots to Talk:Square root algorithms

2025-05-18T19:09:00Z

Fgnievinski moved page Talk:Methods of computing square roots to Talk:Square root algorithms

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Lowercase sigmabot III: Archiving 2 discussion(s) to Talk:Methods of computing square roots/Archive 1) (bot

2024-02-14T15:59:04Z

Archiving 2 discussion(s) to Talk:Methods of computing square roots/Archive 1) (bot

← Previous revision		Revision as of 15:59, 14 February 2024
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	That cryptic constant is actually a composite of three bitfields, and twiddling it requires some understanding of what those fields are. It would be clearer, but a few more operations, to do that line as a pair of bitfield extract/inserts. But we're saving divides in the subsequent iterations, so the extra 1-cycle operations are a wash.		That cryptic constant is actually a composite of three bitfields, and twiddling it requires some understanding of what those fields are. It would be clearer, but a few more operations, to do that line as a pair of bitfield extract/inserts. But we're saving divides in the subsequent iterations, so the extra 1-cycle operations are a wash.

	== {=3 } =4 ==

	In procedure int32_t isqrt(int32_t n)
	* 3 left curly brackets
	* 4 right curly brackets [[User:Jumpow\|Jumpow]] ([[User talk:Jumpow\|talk]]) 20:37, 21 December 2021 (UTC)

	:I tried to fix it. Is it OK now? [[User:JRSpriggs\|JRSpriggs]] ([[User talk:JRSpriggs\|talk]]) 22:57, 22 December 2021 (UTC)
	:: Yes, now OK [[User:Jumpow\|Jumpow]] ([[User talk:Jumpow\|talk]]) 21:33, 4 January 2022 (UTC)

	== Undefined behaviour ==		== Undefined behaviour ==
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	:This basically says, 'you may use a union to reinterpret the bits of one type into another but we're not going to promise that the new interpretation will be valid'		:This basically says, 'you may use a union to reinterpret the bits of one type into another but we're not going to promise that the new interpretation will be valid'
	:I will say that the C code in this article is rather clunky and may benefit from a bitfield to separate the different sections of the float representation so it is easier to read and understand, but I will have to flatly disagree with you that <code>memcpy() </code>is more appropriate than a union in this code snippet. [[User:WillisHershey\|WillisHershey]] ([[User talk:WillisHershey\|talk]]) 17:24, 25 September 2023 (UTC)		:I will say that the C code in this article is rather clunky and may benefit from a bitfield to separate the different sections of the float representation so it is easier to read and understand, but I will have to flatly disagree with you that <code>memcpy() </code>is more appropriate than a union in this code snippet. [[User:WillisHershey\|WillisHershey]] ([[User talk:WillisHershey\|talk]]) 17:24, 25 September 2023 (UTC)

	== binary method in c ==

	I believe that the example that is given in C is what is referred to as the [http://totton.idirect.com/soroban/KojimaSq/ Chinese Abacus Method] - confirmation from [http://medialab.freaknet.org/martin/src/sqrt/ this article] and [http://medialab.freaknet.org/martin/src/sqrt/sqrt.imp code that appears to be the same algorithm.] <!-- Template:Unsigned IP --><small class="autosigned">— Preceding [[Wikipedia:Signatures\|unsigned]] comment added by [[Special:Contributions/70.124.38.160\|70.124.38.160]] ([[User talk:70.124.38.160#top\|talk]]) 15:55, 18 April 2022 (UTC)</small> <!--Autosigned by SineBot-->

	== Lucas sequence method - original research? ==		== Lucas sequence method - original research? ==

JBW: typo

2024-02-13T13:01:13Z

typo

← Previous revision		Revision as of 13:01, 13 February 2024
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	Not sure if this is a known or established property, proven, bounded, or if its already in the article in some alternative capacity, or if its even appropriate for this article. I do know the taylor series approximation with two terms connects these expressions.		Not sure if this is a known or established property, proven, bounded, or if its already in the article in some alternative capacity, or if its even appropriate for this article. I do know the taylor series approximation with two terms connects these expressions.
	[[User:CogitoErgoCogitoSum\|CogitoErgoCogitoSum]] ([[User talk:CogitoErgoCogitoSum\|talk]]) 21:05, 11 February 2024 (UTC)		[[User:CogitoErgoCogitoSum\|CogitoErgoCogitoSum]] ([[User talk:CogitoErgoCogitoSum\|talk]]) 21:05, 11 February 2024 (UTC)
	: There is nothing special about 2 and 4: <math>\sqrt{x+2c} \approx \frac{x+c}{\sqrt{x}}</math> provided that c is small compared to x. This is, in fact, just the ~~firs~~ two terms of the series given in the article under the section heading "Taylor series". [[User:JBW\|JBW]] ([[User talk:JBW\|talk]]) 01:45, 13 February 2024 (UTC)		: There is nothing special about 2 and 4: <math>\sqrt{x+2c} \approx \frac{x+c}{\sqrt{x}}</math> provided that c is small compared to x. This is, in fact, just the first two terms of the series given in the article under the section heading "Taylor series". [[User:JBW\|JBW]] ([[User talk:JBW\|talk]]) 01:45, 13 February 2024 (UTC)

	: I don't think they are useful. In the first, you have replaced a square root and an addition with a square root, an addition, and a division to get an approximate answer. [[User:Bubba73\|Bubba73]] <sup>[[User talk:Bubba73\|You talkin' to me?]]</sup> 08:02, 13 February 2024 (UTC)		: I don't think they are useful. In the first, you have replaced a square root and an addition with a square root, an addition, and a division to get an approximate answer. [[User:Bubba73\|Bubba73]] <sup>[[User talk:Bubba73\|You talkin' to me?]]</sup> 08:02, 13 February 2024 (UTC)

Bubba73: /* Useful addition?? */

2024-02-13T08:02:59Z

Useful addition??

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	[[User:CogitoErgoCogitoSum\|CogitoErgoCogitoSum]] ([[User talk:CogitoErgoCogitoSum\|talk]]) 21:05, 11 February 2024 (UTC)		[[User:CogitoErgoCogitoSum\|CogitoErgoCogitoSum]] ([[User talk:CogitoErgoCogitoSum\|talk]]) 21:05, 11 February 2024 (UTC)
	: There is nothing special about 2 and 4: <math>\sqrt{x+2c} \approx \frac{x+c}{\sqrt{x}}</math> provided that c is small compared to x. This is, in fact, just the firs two terms of the series given in the article under the section heading "Taylor series". [[User:JBW\|JBW]] ([[User talk:JBW\|talk]]) 01:45, 13 February 2024 (UTC)		: There is nothing special about 2 and 4: <math>\sqrt{x+2c} \approx \frac{x+c}{\sqrt{x}}</math> provided that c is small compared to x. This is, in fact, just the firs two terms of the series given in the article under the section heading "Taylor series". [[User:JBW\|JBW]] ([[User talk:JBW\|talk]]) 01:45, 13 February 2024 (UTC)

			: I don't think they are useful. In the first, you have replaced a square root and an addition with a square root, an addition, and a division to get an approximate answer. [[User:Bubba73\|Bubba73]] <sup>[[User talk:Bubba73\|You talkin' to me?]]</sup> 08:02, 13 February 2024 (UTC)

JBW: /* Useful addition?? */ comment

2024-02-13T01:45:31Z

Useful addition??: comment

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	Not sure if this is a known or established property, proven, bounded, or if its already in the article in some alternative capacity, or if its even appropriate for this article. I do know the taylor series approximation with two terms connects these expressions.		Not sure if this is a known or established property, proven, bounded, or if its already in the article in some alternative capacity, or if its even appropriate for this article. I do know the taylor series approximation with two terms connects these expressions.
	[[User:CogitoErgoCogitoSum\|CogitoErgoCogitoSum]] ([[User talk:CogitoErgoCogitoSum\|talk]]) 21:05, 11 February 2024 (UTC)		[[User:CogitoErgoCogitoSum\|CogitoErgoCogitoSum]] ([[User talk:CogitoErgoCogitoSum\|talk]]) 21:05, 11 February 2024 (UTC)
			: There is nothing special about 2 and 4: <math>\sqrt{x+2c} \approx \frac{x+c}{\sqrt{x}}</math> provided that c is small compared to x. This is, in fact, just the firs two terms of the series given in the article under the section heading "Taylor series". [[User:JBW\|JBW]] ([[User talk:JBW\|talk]]) 01:45, 13 February 2024 (UTC)

CogitoErgoCogitoSum: /* Useful addition?? */

2024-02-11T21:48:59Z

Useful addition??

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	== Useful addition?? ==		== Useful addition?? ==
	Not sure if its useful, but I have found that, in general, <math>\sqrt{x+2} \approx \frac{x+1}{\sqrt{x}}</math>, and if {{math\|''x''{{=}}''n''{{sup\|''2''}}}} we get <math>\sqrt{n^2+2} \approx n + \frac{1}{n}</math>.		Not sure if its useful, but I have found that, in general, <math>\sqrt{x+2} \approx \frac{x+1}{\sqrt{x}}</math>, and if {{math\|''x''{{=}}''n''{{sup\|''2''}}}} we get <math>\sqrt{n^2+2} \approx n + \frac{1}{n}</math>.

			Similarly <math>\sqrt{x+4} \approx \frac{x+2}{\sqrt{x}}</math>.

	I sometimes use this for quick pencil and paper calculations, if Im close enough to a convenient value.		I sometimes use this for quick pencil and paper calculations, if Im close enough to a convenient value.

	Not sure if this is a known or established property, proven, bounded, or if its already in the article in some alternative capacity, or if its even appropriate for this article.		Not sure if this is a known or established property, proven, bounded, or if its already in the article in some alternative capacity, or if its even appropriate for this article. I do know the taylor series approximation with two terms connects these expressions.
	[[User:CogitoErgoCogitoSum\|CogitoErgoCogitoSum]] ([[User talk:CogitoErgoCogitoSum\|talk]]) 21:05, 11 February 2024 (UTC)		[[User:CogitoErgoCogitoSum\|CogitoErgoCogitoSum]] ([[User talk:CogitoErgoCogitoSum\|talk]]) 21:05, 11 February 2024 (UTC)

CogitoErgoCogitoSum: /* Merge "Approximations that depend on the floating point representation" into "Initial estimate" */

2024-02-11T21:09:22Z

Merge "Approximations that depend on the floating point representation" into "Initial estimate"

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	Additionally, in my opinion the entirety of the article could benefit from some trimming/rewriting, as many sections contain redundant information, unnecessary details, and awkward formulations. [[User:BlueRavel\|BlueRavel]] ([[User talk:BlueRavel\|talk]]) 14:54, 4 December 2023 (UTC)		Additionally, in my opinion the entirety of the article could benefit from some trimming/rewriting, as many sections contain redundant information, unnecessary details, and awkward formulations. [[User:BlueRavel\|BlueRavel]] ([[User talk:BlueRavel\|talk]]) 14:54, 4 December 2023 (UTC)

			:: Your proposition makes sense to me, and I dont necessarily disagree. That said though, as a pure mathematician, I am uninclined to blur the lines between programmatical issues and mathematical problems. I think maintaining a distinction is appropriate. An analysis of the pure mathematical problem of initial estimation in these abstract reiterative processes is a decidedly distinct discussion from considerations in this programming language, or that programming language, or this architecture, or that architecture. The former is future-proofed, the latter is not. [[User:CogitoErgoCogitoSum\|CogitoErgoCogitoSum]] ([[User talk:CogitoErgoCogitoSum\|talk]]) 21:09, 11 February 2024 (UTC)

	== Useful addition?? ==		== Useful addition?? ==

CogitoErgoCogitoSum: /* Merge "Approximations that depend on the floating point representation" into "Initial estimate" */

2024-02-11T21:05:03Z

Merge "Approximations that depend on the floating point representation" into "Initial estimate"

← Previous revision		Revision as of 21:05, 11 February 2024
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	Additionally, in my opinion the entirety of the article could benefit from some trimming/rewriting, as many sections contain redundant information, unnecessary details, and awkward formulations. [[User:BlueRavel\|BlueRavel]] ([[User talk:BlueRavel\|talk]]) 14:54, 4 December 2023 (UTC)		Additionally, in my opinion the entirety of the article could benefit from some trimming/rewriting, as many sections contain redundant information, unnecessary details, and awkward formulations. [[User:BlueRavel\|BlueRavel]] ([[User talk:BlueRavel\|talk]]) 14:54, 4 December 2023 (UTC)


			== Useful addition?? ==
			Not sure if its useful, but I have found that, in general, <math>\sqrt{x+2} \approx \frac{x+1}{\sqrt{x}}</math>, and if {{math\|''x''{{=}}''n''{{sup\|''2''}}}} we get <math>\sqrt{n^2+2} \approx n + \frac{1}{n}</math>.

			I sometimes use this for quick pencil and paper calculations, if Im close enough to a convenient value.

			Not sure if this is a known or established property, proven, bounded, or if its already in the article in some alternative capacity, or if its even appropriate for this article.
			[[User:CogitoErgoCogitoSum\|CogitoErgoCogitoSum]] ([[User talk:CogitoErgoCogitoSum\|talk]]) 21:05, 11 February 2024 (UTC)

Cewbot: Maintain {{WPBS}} and vital articles: 1 WikiProject template. Create {{WPBS}}. Keep majority rating "C" in {{WPBS}}. Remove 1 same rating as {{WPBS}} in {{Maths rating}}. Remove 1 deprecated parameter: field.

2024-02-06T04:07:55Z

Maintain {{WPBS}} and vital articles: 1 WikiProject template. Create {{WPBS}}. Keep majority rating "C" in {{WPBS}}. Remove 1 same rating as {{WPBS}} in {{Maths rating}}. Remove 1 deprecated parameter: field.

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← Previous revision		Revision as of 08:02, 13 February 2024
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	[[User:CogitoErgoCogitoSum\|CogitoErgoCogitoSum]] ([[User talk:CogitoErgoCogitoSum\|talk]]) 21:05, 11 February 2024 (UTC)		[[User:CogitoErgoCogitoSum\|CogitoErgoCogitoSum]] ([[User talk:CogitoErgoCogitoSum\|talk]]) 21:05, 11 February 2024 (UTC)
	: There is nothing special about 2 and 4: <math>\sqrt{x+2c} \approx \frac{x+c}{\sqrt{x}}</math> provided that c is small compared to x. This is, in fact, just the firs two terms of the series given in the article under the section heading "Taylor series". [[User:JBW\|JBW]] ([[User talk:JBW\|talk]]) 01:45, 13 February 2024 (UTC)		: There is nothing special about 2 and 4: <math>\sqrt{x+2c} \approx \frac{x+c}{\sqrt{x}}</math> provided that c is small compared to x. This is, in fact, just the firs two terms of the series given in the article under the section heading "Taylor series". [[User:JBW\|JBW]] ([[User talk:JBW\|talk]]) 01:45, 13 February 2024 (UTC)

			: I don't think they are useful. In the first, you have replaced a square root and an addition with a square root, an addition, and a division to get an approximate answer. [[User:Bubba73\|Bubba73]] <sup>[[User talk:Bubba73\|You talkin' to me?]]</sup> 08:02, 13 February 2024 (UTC)