there is a problem with for loop
code:

$a=1;
$b=1.5;
$step=0.1;

for ($i=$a;$i<=$b;$i=$i+$step) {
  echo "$i<BR>";
}



prints:
1
1.1
1.2
1.3
1.4


and 1.5 value is skipped
when changing this values
to $a=10;$b=15;$step=1;
everything is OK (15 is printed)
so I guess problem is with floating point values