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<br><br>> Date: Fri, 2 Oct 2009 06:10:37 +1000<br>> From: Mark.Abraham@anu.edu.au<br>> To: gmx-users@gromacs.org<br>> Subject: Re: R: RE: R: RE: R: RE: R: RE: R: RE: R: Re: R:[gmx-users] Tabulated potential - Problem<br>> <br>> Berk Hess wrote:<br>> > Ah, I thought the sentence in one of my previous mails was clear enough:<br>> > "The points in the table_b.xvg file should be equally spaced.<br>> > grompp assumes equal spacing, but does not check this."<br>> > <br>> > I think "should be" and "must be" are equivalent in this context.<br>> > But we can clarify the manual, and add a check in grompp.<br>> <br>> It's close, but in general there is a shade of certainty conveyed by <br>> "must" that is additional to that of "should". The dictionary I have to <br>> hand contrasts "to be obliged or compelled to, as by some constraining <br>> force or necessity" with "to denote duty, propriety, expediency" <br>> respectively. Wiktionary agrees - http://en.wiktionary.org/wiki/must. I <br>> am aware of usage in a body of law where failure to follow a direction <br>> qualified by "must" carries a more severe consequence than failure to <br>> follow a direction qualified by "should".<br>> <br>> Berk is correct in this context, however. The only relevant qualities of <br>> the table are that it be accurate and reasonably efficient. A user <br>> failing to follow "should" would be making an unwarranted assumption <br>> that accuracy and/or efficiency was compromised only to a negligible <br>> degree. "must" is slightly superior in such a context where no purpose <br>> is served by the distinction with "should," and the reader might err <br>> more often when "should" is used. Manual section 6.7.1 certainly <br>> expresses the idea that equal spacing of table points is normal and <br>> expected, but there is no statement which conveys a suitable degree of <br>> definiteness. That could be improved.<br>> <br><br>I am aware of these subtle differences.<br>I am not a native English speaker (although I did live in Australia<br>for 3.5 years during my childhood). But I personally do not like<br>a manual description which repeatedly uses the word "must",<br>it just doesn't sound very friendly. I strongly prefer "should".<br>But we could also use something like "has to have".<br>Anyhow, I'll put a check in grompp, so the user will get a fatal error<br>and can not proceed, even if he/se interprets the manual differently<br>from intended. Such a check doesn't have any disadvantages (except<br>for requiring 5 minutes of coding and checking) and also help to detect<br>mistakes in script generating tables etc.<br>This is becoming more important, as more and more people start using<br>numerically derived potentials.<br><br>Berk<br><br>> Even the use of language can be as exacting as the methods described by <br>> it :-) I tied myself in knots last weekend with an incorrect use of <br>> "abjure" instead of "adjure"...<br>> <br>> Mark<br>> <br><br> <br /><hr />What can you do with the new Windows Live? <a href='http://www.microsoft.com/windows/windowslive/default.aspx' target='_new'>Find out</a></body>
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