Talk:Square root algorithms: Difference between revisions

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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.
 
== {=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 ==
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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'
: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">—&nbsp;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? ==
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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.
[[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 firsfirst 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)