Article View: aus.mathematics
Article #39Re: How to find a formula from a list of numbers
From: Adam Nielsen
Date: Mon, 05 Oct 2009 11:33
Date: Mon, 05 Oct 2009 11:33
37 lines
3033 bytes
3033 bytes
> Note that for A >= 16, doubling A also doubles B'. > The best fit is > B' = A/16 * 1.91, truncated to 1 decimal place. > > 1.91/16 = 0.119375, > and your rational approximation for that is > 1/10 + 1/52 = 31/260 = 0.1192307 > > Note that there are closer rational approximations, but any one that > provides the correct B' values to 1 decimal place is close enough. Ah, glad to see I was close! Thanks again. I've got all the current values sorted now, but I've discovered that the fan speeds seem to be reported on some sort of logarithmic scale: A | B ------+--------- 128 | 8943 RPM / 943 RPM * 144 | 9727 RPM * 256 | 5493 RPM 512 | 2746 RPM 1285 | 1094 RPM 4096 | 343 RPM 8192 | 171 RPM 65535 | 21 RPM I'm not 100% sure about the first two values (marked with *) because the values were so large I'm not sure the manufacturer's program was drawing them on the screen properly. I *think* this is logarithmic - I can get an approximation of the curve using variations of -log(x), but I'm afraid that's as far I as can remember :-) If it's possible, an approximation using "simpler" operations (+, -, *, /) would be even better from a runtime efficiency point of view! Thanks again, Adam.
Technical Details
Message-ID:
<EK-dnV5FoYzmRFTXnZ2dnUVZ_jKdnZ2d@westnet.com.au>Path:
arc1-ca.pugleaf.net!g2news2.google.com!news1.google.com!Xl.tags.giganews.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local2.nntp.dca.giganews.com!nntp.westnet.com.au!news.westnet.com.au.POSTED!not-for-mailReferences:
<JOqdnbc8ud5gPFXXnZ2dnUVZ_v6dnZ2d@westnet.com.au> <ik9hc59at0uhkd54jr78j3ba55a8j7cesm@4ax.com> <see-3529E1.08572405102009@mail.eternal-september.org> <FtadnaK-YsVEvVTXnZ2dnUVZ_oKdnZ2d@westnet.com.au> <mq6dnbOR7_Sjv1TXnZ2dnUVZ_r6dnZ2d@westnet.com.au> <see-F90A00.12401205102009@mail.eternal-september.org>Show Full Headers
Complete Article Headers
X-Google-Thread: dfcd5d83b8,ea449aa0d72efcd3 X-Google-Attributes: giddfcd5d83b8,public,usenet X-Google-NewGroupId: yes X-Google-Language: ENGLISH,ASCII-7-bit Path: arc1-ca.pugleaf.net!g2news2.google.com!news1.google.com!Xl.tags.giganews.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local2.nntp.dca.giganews.com!nntp.westnet.com.au!news.westnet.com.au.POSTED!not-for-mail NNTP-Posting-Date: Mon, 05 Oct 2009 06:33:15 -0500 Date: Mon, 05 Oct 2009 21:33:13 +1000 From: Adam Nielsen <a.nielsen@remove.this.shikadi.net> User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-GB; rv:1.8.1.22) Gecko/20090809 Thunderbird/2.0.0.22 Mnenhy/0.7.5.0 MIME-Version: 1.0 Newsgroups: aus.mathematics Subject: Re: How to find a formula from a list of numbers References: <JOqdnbc8ud5gPFXXnZ2dnUVZ_v6dnZ2d@westnet.com.au> <ik9hc59at0uhkd54jr78j3ba55a8j7cesm@4ax.com> <see-3529E1.08572405102009@mail.eternal-september.org> <FtadnaK-YsVEvVTXnZ2dnUVZ_oKdnZ2d@westnet.com.au> <mq6dnbOR7_Sjv1TXnZ2dnUVZ_r6dnZ2d@westnet.com.au> <see-F90A00.12401205102009@mail.eternal-september.org> In-Reply-To: <see-F90A00.12401205102009@mail.eternal-september.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Message-ID: <EK-dnV5FoYzmRFTXnZ2dnUVZ_jKdnZ2d@westnet.com.au> Lines: 37 X-Usenet-Provider: http://www.giganews.com NNTP-Posting-Host: 203.217.41.238 X-Trace: sv3-ep9KVn5D4R3jjcCgLQxPK/iUBc4RLii9NtcLdfAhywhnQL4xMsx8LlueXk2cVwhr1Q3edQQLDHf/04j!Ifj0Id1W/kqjNc3YvIce4JD12nJfhKxSLtE8pBBZ8tcZS/iEdHwLTGAtF2kcUynrz2wwBJcUg8Ik!a5Q41oMzAAxbkPG34Vsmhg== X-Complaints-To: abuse@westnet.com.au X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.40