[Rd] Wierd nlm behaviour in 2.10.1 and 2.12.0 [Sec=Unclassified]

[Troy Robertson]

Hi all,

When upgrading to 2.11.1 recently I noticed different results being produced by my code.
After MUCH digging into my code I have finally narrowed it to a call to nlm().
The problem actually occurs in 2.10.1 and 2.12.0.

This can be replicated by trying the code below in some different versions of R:

FixedRemovals<-1836180125888
AbStageInitial<-2223033830403
Rates<- 0.3102445
myfunc<-function(rootM,Abund,Loss,OtherM)
     {(Loss-(rootM/(rootM+OtherM)*
      (1-exp(-(rootM+OtherM)))*
      Abund))^2}

nlm(myfunc
   ,0.001,print.level=0,fscale=0, gradtol=1E-10, stepmax = 100.0
   ,Loss=FixedRemovals
   ,Abund=AbStageInitial
   ,OtherM=Rates)

nlm(myfunc
   ,0.001,print.level=0,fscale=0, gradtol=1E-10, stepmax = 100.0
   ,Loss=FixedRemovals
   ,Abund=AbStageInitial
   ,OtherM=Rates)$estimate

Why would I be seeing a different value of 'estimate' (or any of the other returned list items)?
Originally I thought it was 2.11.1 that was giving me the grief with different output but now I see that in 2.11.1 I get the same value to each returned list item both ways.
Can anyone explain this?

Thanks

Troy
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