On Fri 20-Jun-08 11:20pm -0600, Ben Schmidt wrote:
>
> Bill McCarthy wrote:
>> On Fri 20-Jun-08 3:08pm -0600, Bram Moolenaar wrote:
>>> Ben Schmidt wrote:
>>>> - No chance of getting sin(), cos(), atan() and log10()? I realised
>>>> after thinking a bit further and reading some other users' posts that
>>>> these actually would truly be useful. Surely they would only take a
>>>> few minutes to implement, no time to maintain, and I would have a lot
>>>> of use for them. I don't know how many users are like me, but there
>>>> must be a few as surely programming is fairly closely related to
>>>> mathematics in many ways. (I'd like exp() and log() as well, but these
>>>> can be done with pow() and log10() by appropriately defining e, so not
>>>> an issue. tan(), sgn(), rand(), etc. are easy with scripts, too, so no
>>>> problems there.)
>>
>>> log10() is there. I don't see a use for sin() and the like. If you
>>> really want these please come up with an example.
>>
>> It's useful to have a calculator available at your
>> fingertips and to be able to create tables in Vim which are
>> easy when the math functions are there.
>>
>> I see you have log10, pow and sqrt now. In a few minutes I
>> added log and exp to both Vim and Gvim. In another 10
>> minutes I could have added sin, cos, tan, asin, acos, atan
>> and, modeling after pow, atan2 - but I don't like the idea
>> of needing to patch eval.c every time you make a change.
>>
>> Since there is virtually no overhead or maintenance, the
>> question becomes why not just add them.
>>
>> If you don't have the time, others can do this - I, Ben or
>> others would likely be happy to make the patch.
>
> You bet!
>
> The ones I suggested really were just the bare bones that couldn't be
> easily scripted based on others, and which are more traditionally
> included in minimalist mathematics libraries.
>
> I for one certainly wouldn't mind having a fuller set! For purposes of
> accuracy, using the library functions is better than layering scripts on
> top, too. But I wouldn't be too upset with a slimmer set either, as long
> as that slimmer set uses the library functions so at least one layer of
> inaccuracy is removed. But not having even those essentials I mentioned
> in my previous post would be a real shame in my eyes.
>
> Two more suggestions: How about v:inf and v:nan? Then we wouldn't need
> to resort to ugliness such as str2float('inf') or (1.0/0) to do this.
>
> Ben.
>
>
>
> P.S. Given v:e, v:pi, sin(), cos(), atan(), sqrt() and pow() we can get:
>
> exp(x) = pow(v:e,x)
> log(x) = log10(x)/log10(v:e)
> sinh(x) = (pow(v:e,x)-pow(v:e,-x))/2
> cosh(x) = (pow(v:e,x)+pow(v:e,-x))/2
> tanh(x) = (pow(v:e,x)+pow(v:e,-x))/2
> tan(x) = sin(x)/cos(x)
> atan2(y,x) = x==0 ? ( y>0 ? v:pi/2 : -v:pi/2 )
> : ( x>0 ? ( y>0 ? atan(y/x) : atan(y/x)+2*v:pi )
> : atan(y/x)+v:pi )
> acos(x) = x==0 ? v:pi/2
> : ( x>0 ? atan(sqrt(1/pow(x,2)-1))
> : v:pi-atan(sqrt(1/pow(x,2)-1)) )
> asin(x) = x==1 ? v:pi/2
> : ( x==-1 ? -v:pi/2
> : ( x>0 ? atan(sqrt(1/(1-pow(x,2))-1))
> :
> -atan(sqrt(1/(1-pow(x,2))-1)) ))
>
> You can see how ugly this is, how many operations it involves and thus
> increases room for inaccuracy to creep in, and thus why the fuller set
> would be nice, but also that it's possible to script once you have the
> essentials. These are not even full implementations, as they don't
> account for all the +-0 and +-infinity subtleties, either (which is why
> v:inf would be a nice bare bones thing to have!). And I haven't tested
> them, and with such ugliness there are probably errors. But you get the
> gist.I'm not sure how to add the variables. Bram already includes, log10, pow and sqrt. I've patched 7.1.386 with the new floating point patch. The attached patch to that includes log, exp, sin, cos, tan, asin, acos, atan and atan2. Caution - it's DOS format and is applied from the src directory. -- Best regards, Bill --~--~---------~--~----~------------~-------~--~----~ You received this message from the "vim_dev" maillist. For more information, visit http://www.vim.org/maillist.php -~----------~----~----~----~------~----~------~--~---
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