def __init__(self, minrps, maxrps, duration):
self.minrps = float(minrps)<EOL>self.maxrps = float(maxrps)<EOL>self.duration = duration / <NUM_LIT><EOL>self.slope = (self.maxrps - self.minrps) / self.duration<EOL>
:param minrps:
:param maxrps:
:param duration: milliseconds