# dwhite@nist.gov 3/23/04  - based on BASIC code
# in "Astronomical Algorithms" 2nd ed. by Jean Meeus,
# pg 17-19

# start of code block 1
$x = 1 ;
$j = 0 ;
$x *= 2 ;
print "Testing significant bits, significant digits...\n"; 

while (($x + 1) != $x) {
  print "\t$j\t$x\n"; 
  $j++ ;
  $x *= 2 ;
}
print "\t$j\t$x\n"; 
print "\n", $j , " significant bits in mantissa of floating number\n" 
+, int($j * 0.30103) , " significant digits in a decimal number (", $j
+ * 0.30103 , ")\n above is only for SIMPLE ARITHMETICS, not trig func
+tions!\n";
# end of code block 1

print "\nthe 2nd column here should NOT list diverging numbers...\n";
print "\$x=1.0/3.0;  
for(\$j=1;\$j<31;\$j++) { \$x = (9*\$x+1)*\$x-1 ; }\n";

# start of code block 2
$x = 1.0/3.0 ;
for($j=1;$j<31;$j++) {
    $x = (9*$x+1)*$x-1 ;
    # print "$j\t$x\n"; # for details
    if ($j % 6 == 1) { print "$j\t$x\n"; }
}
print "However, they probably will diverge on your machine.\n";
# end of code block 2
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