#!usr/bin/perl
#
# MWR 4/11/2007

use POSIX;


##########################################################################
# walk through frequences around resonance
#

$outfile = "./forced_amp_a.out";
open(OUTFILE, ">$outfile") || die("can't open file $outfile");
$k = 30;
$m = 2.0;
$b = 2.0;
$amp = 1.0;
$phi = 0.0;
$f_d = 10.0;

$omega_0 = sqrt($k/$m);

$omega_start = 0.1;
$omega_end = 20.0;
$domega = 0.01;
for ($omega = $omega_start; $omega <= $omega_end; $omega += $domega) {


  $top = $f_d / $m;
  $x1 = ($omega*$omega - $omega_0*$omega_0)**2.0;
  $x2 = ($b*$omega/$m)**2.0;
  $bot = sqrt ( $x1 + $x2 );
  
  $amp = $top / $bot;
  printf OUTFILE ("  omega %12.5e  amp %12.5e \n", $omega, $amp);
}
close(OUTFILE);




exit 0;