minimize powell <minimize-powell-statement> end

<minimize-powell-statement> :==

  nstep=<integer>
  --{Number of minimization steps to perform. Default=500}
  drop=<real>
  --{Expected initial drop in total energy. Default=0.001}
  tolgradient=<real>
  --{Tolerence for early termination of minimization. If the norm 
     of the gradient of the total energy falls below this value 
     minimization will stop. Default=0.0001}
  debug=<logical>
  --{Write verbose messages during minimization. Default=false}
  nprint=<integer>
  --{Frequency of printing energy values. Default=1}