R Under development (unstable) (2026-02-10 r89394 ucrt) -- "Unsuffered Consequences"
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> # Test for bad output when exact initial values are supplied (from John Nash)
> 
> require(BB)
Loading required package: BB
> 
> maxfn<-function(x) {
+ 	       n<-length(x)
+        ss<-seq(1,n)
+        f<-10-(crossprod(x-ss))^2
+        f<-as.numeric(f)
+        return(f)
+ }
> 
> x0<-c(1,2,3,4)
> ans.spgm <- spg(x0, maxfn,control=list(maximize=TRUE,trace=TRUE), quiet=TRUE)
iter:  0  f-value:  10  pgrad:  0 
> 
> if ( 10.0 != ans.spgm$value)  stop(
+    "spg is not returning correct value when given optimum starting point.")
>    
> if ( ! all( 0 == (ans.spgm$par - c(1,2,3,4))))  stop(
+    "spg is not returning correct par when given optimum starting point.")
> 
> proc.time()
   user  system elapsed 
   0.14    0.04    0.17