R Under development (unstable) (2024-09-04 r87094 ucrt) -- "Unsuffered Consequences"
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> library(sp)
> data(meuse)
> library(gstat)
> v=variogram(log(zinc)~1,~x+y,meuse,cutoff=500,wi=100)
> v$gamma=c(0.5,1,2,3,3)
> fit.variogram(v, vgm(1, "Sph", 300, 0),warn.if.neg=TRUE)
  model    psill   range
1   Nug 0.000000    0.00
2   Sph 7.878195 1567.77
Warning message:
In fit.variogram(v, vgm(1, "Sph", 300, 0), warn.if.neg = TRUE) :
  partial sill or nugget fixed at zero value
> fit.variogram(v, vgm(1, "Sph", 300, 0),warn.if.neg=FALSE)
  model    psill   range
1   Nug 0.000000    0.00
2   Sph 7.878195 1567.77
> 
> proc.time()
   user  system elapsed 
   0.90    0.15    1.06