braninsc <- function(xx)
{
  ##########################################################################
  #
  # BRANIN FUNCTION, RESCALED
  #
  # Authors: Sonja Surjanovic, Simon Fraser University
  #          Derek Bingham, Simon Fraser University
  # Questions/Comments: Please email Derek Bingham at dbingham@stat.sfu.ca.
  #
  # Copyright 2013. Derek Bingham, Simon Fraser University.
  #
  # THERE IS NO WARRANTY, EXPRESS OR IMPLIED. WE DO NOT ASSUME ANY LIABILITY
  # FOR THE USE OF THIS SOFTWARE.  If software is modified to produce
  # derivative works, such modified software should be clearly marked.
  # Additionally, this program is free software; you can redistribute it 
  # and/or modify it under the terms of the GNU General Public License as 
  # published by the Free Software Foundation; version 2.0 of the License. 
  # Accordingly, this program is distributed in the hope that it will be 
  # useful, but WITHOUT ANY WARRANTY; without even the implied warranty 
  # of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 
  # General Public License for more details.
  #
  # For function details and reference information, see:
  # http://www.sfu.ca/~ssurjano/
  #
  ##########################################################################
  #
  # INPUT:
  #
  # xx = c(x1, x2)
  #
  ##########################################################################
  
  x1 <- xx[1]
  x2 <- xx[2]
  
  x1bar <- 15*x1 - 5
  x2bar <- 15 * x2
  
  term1 <- x2bar - 5.1*x1bar^2/(4*pi^2) + 5*x1bar/pi - 6
  term2 <- (10 - 10/(8*pi)) * cos(x1bar)
  
  y <- (term1^2 + term2 - 44.81) / 51.95
  return(y)
}