/**
* Creates a sequence of evenly spaced values starting at {@code min} and
* ending at {@code max}. If {@code (max - min) / step} is not integer
* valued, the last step in the sequence will be {@code <step}.
* @param min sequence value
* @param max sequence value
* @param step sequence spacing
* @param ascending if {@code true}, descending if {@code false}
* @return a monotonically increasing or decreasing sequence of values
*/
public static function buildSequence($min, $max, $step, $ascending)
{
// if passed in arguments are NaN, +Inf, or -Inf, and step <= 0,
// then capacity [c] will end up 0 because (int) NaN = 0, or outside the
// range 1:10000
$c = intval(($max - $min) / $step);
if ($c <= 0) {
return;
} else {
if ($c >= RTGM_Util::MAX_SEQ_LEN) {
throw new Exception("RTGM_Util::buildSequence: max sequence " . "length reached: " . RTGM_Util::MAX_SEQ_LEN);
}
}
if ($ascending) {
return RTGM_Util::makeSequence($min, $max, $step, $c + 2);
}
$descSeq = RTGM_Util::makeSequence(-$max, -$min, $step, $c + 2);
return RTGM_Util::flip($descSeq);
}
