enculé

    f <- function(x){
      return( x[1]^2 + x[2]^2)
    }

    onePlusOnesES <- function(s1,lambda,precision){
      m <- runif(2,min = -5, max=5)
      fm <- f(m)
      dyn =   c(fm)
      w <- log (s1 +0.5) - log(1:s1)

      while(abs(fm)>precision){
        children <- array(dim=c(lambda,2))
        fchildren <- c()
        for(i in 1:lambda){
          xprime <- m + rnorm(n=2,mean =0,sd = s1)
          fxprime <- f(xprime)
          children[1,] <- xprime
          fchildren <- c(fchildren,fxprime)
        }

        ind <- order(fchildren)
        m <- c(0,0)
        for(j in 1:s1){
          m <- m + w[j] * children[ind[j],]
        }
        fm <- f(m)
        dyn <- c(dyn,fm)
      }

      return(list(x=m, dyn=u))
    }

    main <- function(){
      res <- onePlusOnesES(0.1,100,10^-3)
      cat(res$x,"\n")
      res1 <- onePlusOnesES(0.1,100,10^-8)
      res2 <- onePlusOnesES(0.1,100,10^-8)
      plot(res$dyn, log="xy", ylim=c(10^-10, 100), xlim=c(1,1000), type="l")
      lines(res1$dyn, col="red")
      lines(res2$dyn, col="blue")
    }