R Under development (unstable) (2024-01-22 r85820 ucrt) -- "Unsuffered Consequences"
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> #////////////////////////////
> #// fonction de dispersion des graines (Colbach et al. 2000b)
> #////////////////////////////
> # Exemple:
> # distance = seq(1,1.5, by=0.05)
> # plot(x=distance, y = fseed(distance))
> 
> fseed=function  ( distance) 
+ {
+  grainesB =  1.38930;
+  grainesC =  2.08686;
+ 
+    fd = (grainesB * grainesC) * distance **(grainesC-2) *
+          exp(-grainesB * distance ** (grainesC)) / (2.0*pi);
+  
+   return(fd);
+ }
> 
> #////////////////////////////
> #// f1: la fonction de dispersion du pollen de Klein
> #////////////////////////////
> # Exemple:
> #a=matrix(distance, ncol=1)
> #b= apply(a,1,fpollen)
> # plot(x=distance, y =b)
> # lines(x=distance, y = fseed(distance))
> 
> fpollen = function ( distance)
+ {
+  r = distance
+ 
+   if ( r<=1.5 ) {
+     rt = 0.340-0.405*r+0.128*r**(2.0);
+   }  else {
+     if (r <= 50) {
+       rt = 0.03985/(1+r**(3.12)/3.80);
+     }
+     else {
+       rr = 50
+     gamma = -2.29
+ #    //valeur la plus lourde -2.14, + légère - 2.56
+     K = (0.03985 / (1.0+rr**(3.12)/3.80)) / (1.0+ rr)**gamma
+     rt = K * (1.0 + r)**gamma
+ }      
+   }
+ 
+   return (rt);
+ } 
> 
> proc.time()
   user  system elapsed 
   0.10    0.04    0.14