Reusser <reu### [at] chorusnet> wrote:
:>   Isn't log(e) equal to 1?

: It depends who you ask.  log BASE E of e is one, but pov-ray assumes that the
: base is 10.

  Wrong. POV-Ray assumes that the base is e.

-- 
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -

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Warp wrote:

>   Wrong. POV-Ray assumes that the base is e.

Well I stand corrected.  It still works either way, so I guess you can just change
it to 1.

 - Rico

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Warp wrote:

>   Wrong. POV-Ray assumes that the base is e.

Wait a minute.  I made my assumption on the fact that pov-ray has a ln keyword.  I
assumed that that meant there was also a natural log in which case log would be
base 10.  If this is not the case, then what does ln do?

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Reusser <reu### [at] chorusnet> wrote:
: Wait a minute.  I made my assumption on the fact that pov-ray has a ln keyword.  I
: assumed that that meant there was also a natural log in which case log would be
: base 10.  If this is not the case, then what does ln do?

  POV-Ray 3.1 doesn't have an ln() function. The log() function is used
as natural logarithm.

  However, it seems that this will be changed in POV-Ray 3.5...

-- 
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -

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Reusser <reu### [at] chorusnet> wrote:
: Well I stand corrected.  It still works either way, so I guess you can just change
: it to 1.

  Or just remove it, as dividing by 1 doesn't change anything.

-- 
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -

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Warp wrote:

>   POV-Ray 3.1 doesn't have an ln() function. The log() function is used
> as natural logarithm.
>
>   However, it seems that this will be changed in POV-Ray 3.5...

MegaPov .714 has a keyword "ln" that turns blue when I type it in.  What does that do
if it's not a natural log function?

 -Rico

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Hi all,

> And here's the macro:
>
> #declare e = 2.718281828459;
> #macro gauss(RSR)
>   sqrt(-2*log(rand(RSR))/log(e))*cos(2*pi*rand(RSR))
> #end
>

I tried it and Pov-Ray assumes "log" is in base e, so log(e)=1 and you don't
need it.

But the formula would stand correct if you assume log is in base 10 because
of the base change formula log BASE e(x) = log BASE 10(x) / log BASE 10(e)

Greets
Pablo Viojo.-
pvi### [at] adinetcomuy

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Sorry, I mailed this direct to you. I just misused Outlook...

How about this:

#macro Gauss2(RS,w)
 #local i=w;
 #local r=0;
 #while (i>0)
  #local r=r+rand(RS)/w;
  #local i=i-1;
 #end
 r
#end

RS... Random Seed
w... "width" of the distribution (the higher w, the narrower the dist.)

produces values between 0 and 1, with the maximum at 0.5

Here's a simple test scene (add the above macro at the top):

#declare spectrum
=array[30]{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}

#declare i=0;
#declare R=seed(1712942);
#while(i<10000)
 #declare r=Gauss2(R,2)*30;
 #declare spectrum[int(r)]=spectrum[int(r)]+1/50;
 #declare i=i+1;
#end

#declare _x=0;
#while (_x<30)
 box{
  <_x,0,-0.5>,<_x+1,spectrum[_x],0.5>

ment{ 
   color rgb <1,0.2,0.2>
  }                     
  finish{
   ambient 0.2
   specular 1
   brilliance 0.6
   roughness 0.1
  }
 }
 #declare _x=_x+1;
#end  
                
                
camera {
 location <15,50,-80>
 look_at <15,30,0>
}                

light_source {
 <-20,50,-50>*100
 color rgb 1
}

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Michael Zier <zie### [at] atlantiswh2tu-dresdende> wrote:
: #declare spectrum
: =array[30]{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}

  Wouldn't it be easier to initialize that with a #while-loop? Specially
if you want a lot more items...

-- 
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -

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Warp <war### [at] tagpovrayorg> schrieb in im Newsbeitrag:
3b46ec68@news.povray.org...
> Michael Zier <zie### [at] atlantiswh2tu-dresdende> wrote:
> : #declare spectrum
> : =array[30]{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}
>
>   Wouldn't it be easier to initialize that with a #while-loop? Specially
> if you want a lot more items...
>
Sure, *g*

> --
> #macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
> rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
> ],13),8)-3,10>#end blob{N(array[6]{11117333955,
> 7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -

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