R Under development (unstable) (2026-02-10 r89394 ucrt) -- "Unsuffered Consequences"
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> # test results in these files are indicated for
> # Windows WP Professional v5.1 SP2
> # Linux32 Ubuntu 7.10 desktop 32 bit kernel 2.6.22-14-generic on Intel Pentium
> # Linux64 Gentoo   64 bit kernel 2.6.17-gentoo-r8 on AMD 64 X2
> 
> options(digits=12)
> if(!require("BB"))stop("this test requires package BB.")
Loading required package: BB
> if(!require("setRNG"))stop("this test requires setRNG.")
Loading required package: setRNG
> 
> # Use a preset seed so test values are reproducable. 
> test.rng <- list(kind="Wichmann-Hill", normal.kind="Box-Muller", seed=c(979,1479,1542))
> old.seed <- setRNG(test.rng)
> 
> ##########
> cat("BB test brown.f ...\n")
BB test brown.f ...
> 
> brown.f <- function(x) {
+ p <- x
+ n <- length(p)
+ odd <- seq(1,n,by=2)
+ even <- seq(2,n,by=2)
+ sum((p[odd]^2)^(p[even]^2 + 1) + (p[even]^2)^(p[odd]^2 + 1))
+ }
> 
> #p0 <- rnorm(500,sd=2) # this set fails in optim, so
> p0 <- rnorm(50,sd=2)
> system.time(ans.spg <- spg(par=p0, fn=brown.f, control=list(maxit=2500)))[1]
iter:  0  f-value:  3.15394862062e+22  pgrad:  6.49725878636e+23 
iter:  10  f-value:  259058613.368  pgrad:  1195397396.68 
iter:  20  f-value:  325936.123185  pgrad:  1252880.9224 
iter:  30  f-value:  2140.1416147  pgrad:  1396.58363423 
iter:  40  f-value:  93.0014118948  pgrad:  6.45816697897 
user.self 
     0.15 
> 
> z <- sum(ans.spg $par)
> #good  <-    -3.336592920523865e-05 
> good <- -2.5e-06  # windows
> #on Windows -3.337359033283664e-05
> #on Linux64 -3.383384527412175e-05
> #on Linux32 -3.336592920523865e-05
> print(z, digits=16)
[1] -2.044502465647949e-06
> if(any(abs(good - z) > 1e-5)) stop("BB test brown.f a FAILED")
> 
> 
> proc.time()
   user  system elapsed 
   0.34    0.01    0.34