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#declare KuenSurface = parametric {
function (2*sqrt(1+u^2)*cos(u-atan2(u,1))*sin(v))/(1+u^2*sin(v)^2),
(2*sqrt(1+u^2)*sin(u-atan2(u,1))*sin(v))/(1+u^2*sin(v)^2),
log(tan(.5*v))+(2*cos(v))/(1+u^2+sin(v)^2)
<0,0>,<2*pi,pi>
<-5,-5,-5>,<5,5,5>
}
any help appreciated :-)
--
David Fontaine <dav### [at] faricy net> ICQ 55354965
Please visit my website: http://www.faricy.net/~davidf/
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From: david sharp
Subject: Re: Float factor expected but log found instead
Date: 21 May 2000 23:55:58
Message: <3928afce@news.povray.org>
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David Fontaine <dav### [at] faricynet> wrote in message
news:3928ADAE.15F2E71E@faricy.net...
> #declare KuenSurface = parametric {
> function (2*sqrt(1+u^2)*cos(u-atan2(u,1))*sin(v))/(1+u^2*sin(v)^2),
> (2*sqrt(1+u^2)*sin(u-atan2(u,1))*sin(v))/(1+u^2*sin(v)^2),
> log(tan(.5*v))+(2*cos(v))/(1+u^2+sin(v)^2)
> <0,0>,<2*pi,pi>
> <-5,-5,-5>,<5,5,5>
> }
>
In function{}'s it is 'ln' instead of 'log'
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david sharp wrote:
> In function{}'s it is 'ln' instead of 'log'
Ah, muchas gracias.
--
David Fontaine <dav### [at] faricynet> ICQ 55354965
Please visit my website: http://www.faricy.net/~davidf/
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From: Matthew Bennett
Subject: Re: Float factor expected but log found instead
Date: 23 May 2000 08:07:39
Message: <392a748b@news.povray.org>
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"david sharp" <dsh### [at] interportnet> wrote in message
news:3928afce@news.povray.org...
>
> David Fontaine <dav### [at] faricynet> wrote in message
> news:3928ADAE.15F2E71E@faricy.net...
> > #declare KuenSurface = parametric {
> > function (2*sqrt(1+u^2)*cos(u-atan2(u,1))*sin(v))/(1+u^2*sin(v)^2),
> > (2*sqrt(1+u^2)*sin(u-atan2(u,1))*sin(v))/(1+u^2*sin(v)^2),
> > log(tan(.5*v))+(2*cos(v))/(1+u^2+sin(v)^2)
> > <0,0>,<2*pi,pi>
> > <-5,-5,-5>,<5,5,5>
> > }
> >
>
> In function{}'s it is 'ln' instead of 'log'
Isn't that to base e rather than base 10 though?
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From: david sharp
Subject: Re: Float factor expected but log found instead
Date: 23 May 2000 09:01:51
Message: <392a813f@news.povray.org>
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Matthew Bennett <ben### [at] btinternetcom>
> "david sharp" <dsh### [at] interportnet> wrote
>
> > In function{}'s it is 'ln' instead of 'log'
>
> Isn't that to base e rather than base 10 though?
>
In the isosurface patch ln is actually log base 10.
or, actually, ln(x) = log_10(abs(x)) . I kind of remember
learning that the 'n' in 'ln' was because ln was supposed
to be 'natural' logarithm. Perhaps the 'n' in the isosurface
patch ln is for 'nice'.
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On Tue, 23 May 2000 09:02:36 -0400, david sharp wrote:
>
>Matthew Bennett <ben### [at] btinternetcom>
>> "david sharp" <dsh### [at] interportnet> wrote
>>
>> > In function{}'s it is 'ln' instead of 'log'
>>
>> Isn't that to base e rather than base 10 though?
>>
>
>In the isosurface patch ln is actually log base 10.
>or, actually, ln(x) = log_10(abs(x)) .
I don't see that in the superpatch 3.1g code (I don't have MegaPOV code
handy on this machine.) Specifically, it says
LOG( ABS( *calc_stack_top ))
where LOG is defined in isofunc.h as 'log'. A quick 'man log' shows
that 'log' is the C function for natural logarithm, and 'log10' is the
base-10 logarithm.
If that's different in MegaPOV, it should probably be put back.
--
Ron Parker http://www2.fwi.com/~parkerr/traces.html
These are my opinions. I do NOT speak for the POV-Team.
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From: david sharp
Subject: Re: Float factor expected but log found instead
Date: 23 May 2000 23:32:24
Message: <392b4d48@news.povray.org>
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Ron Parker <ron### [at] povrayorg> wrote
>
> LOG( ABS( *calc_stack_top ))
>
> where LOG is defined in isofunc.h as 'log'. A quick 'man log' shows
> that 'log' is the C function for natural logarithm, and 'log10' is the
> base-10 logarithm.
>
Oh, that's right.
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From: Warp
Subject: Re: Float factor expected but log found instead
Date: 24 May 2000 03:59:47
Message: <392b8bf2@news.povray.org>
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david sharp <dsh### [at] interportnet> wrote:
: In the isosurface patch ln is actually log base 10.
In my opinion, if this is so, it's very wrong. 'ln' has always been
logarithm base e.
--
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/
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From: Thorsten Froehlich
Subject: Re: Float factor expected but log found instead
Date: 24 May 2000 07:47:33
Message: <392bc155@news.povray.org>
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In article <392b8bf2@news.povray.org> , Warp <war### [at] tagpovrayorg> wrote:
> In my opinion, if this is so, it's very wrong. 'ln' has always been
> logarithm base e.
As you know, the isosurface patch has plenty of differences from the
official POV-Ray functions. Hopefully all these annoying differences will
be corrected in POV-Ray 3.5.
Thorsten
____________________________________________________
Thorsten Froehlich
e-mail: mac### [at] povrayorg
I am a member of the POV-Ray Team.
Visit POV-Ray on the web: http://mac.povray.org
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From: david sharp
Subject: Re: Float factor expected but log found instead
Date: 24 May 2000 08:48:34
Message: <392bcfa2@news.povray.org>
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Thorsten Froehlich <tho### [at] trfde> wrote
> In article <392b8bf2@news.povray.org> , Warp <war### [at] tagpovrayorg> wrote:
>
> > In my opinion, if this is so, it's very wrong. 'ln' has always been
> > logarithm base e.
>
I was mistaken. I have been believing that the standard C language log was
log_10 when it's actually log_e. I have also known that it was log_e, since
I have had to use it correctly many times, but I have to relearn this fact
every
time
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