R Under development (unstable) (2026-02-10 r89394 ucrt) -- "Unsuffered Consequences"
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> require(BB)
Loading required package: BB
> 
> # from projectLinear.Rd
> 
> fn <- function(x) (x[1] - 3/2)^2 + (x[2] - 1/8)^4
> 
> gr <- function(x) c(2 * (x[1] - 3/2) , 4 * (x[2] - 1/8)^3)
> 
> Amat <- matrix(c(1, -1, 1, 1, -1, 1, -1, -1), 4, 2, byrow=TRUE)
> b <- c(-1, -1, -1, -1)
> meq <- 0  # all 4 conditions are inequalities
> 
> p0 <-  c( -0.3599199, -1.2219309)
> 
> r1 <- spg(par=p0, fn=fn, gr=gr, project="projectLinear", 
+         projectArgs=list(A=Amat, b=b, meq=meq))
iter:  0  f-value:  6.750707  pgrad:  1.78621 
> 
> if(any(1e-14 < r1$par - c(1,0))) stop("projectLinear test 1 failed.")
> 
> 
> meq <- 1  # first condition is now an equality
> r2 <- spg(par=p0, fn=fn, gr=gr, project="projectLinear", 
+         projectArgs=list(A=Amat, b=b, meq=meq))
iter:  0  f-value:  6.750707  pgrad:  1 
> 
> if(any(1e-14 < r2$par - c(0,1))) stop("projectLinear test 2 failed.")
> 
> # box-constraints 
> 
> Amat <- matrix(c(1, 0, 0, 1, -1, 0, 0, -1), 4, 2, byrow=TRUE)
> b <- c(0, 0, -0.5, -0.5)
> 
> r3 <- spg(par=p0, fn=fn, gr=gr, project="projectLinear", 
+             projectArgs=list(A=Amat, b=b, meq=0))
iter:  0  f-value:  6.750707  pgrad:  0.5 
iter:  10  f-value:  1  pgrad:  4.446537e-06 
> 
> if(any(1e-14 < r3$par - c(0.5, 0.1146409327454269))
+   ) stop("projectLinear test 3 failed.")
> 
> 
> proc.time()
   user  system elapsed 
   0.12    0.07    0.18