while(<file>)
{
if (/create_clock\s+(\S+)\s+(\S+)\s+(\S+)\s+(\S+)*/ )  {

            $CLK1{$2}= $4;
            print clk_file ;
            
elsif (/set_input_clock\s+(\d+)\s+(\S+)\s+(\S+)\s+\"(\w+)\"\s+(\S+)*/ ) 
       { 
         $d =$1;
         $c =$4; 
         if ($delay < 0) {

print clk_file "set_input_clock 0 $2   $3 $4  $5 \n";
	    next;
	 }
         if (exists $CLK{$c}) 
	 {
	       if ($CLK{$c}*0.95 < $d) 
	    {
	       printf clk_file "set_input_clock %.6f $2   $3 $4  $5 \n",$CLK{$c}*0.5;
	    }
	   else{print clk_file;}
	    
         }