S<[B<--start>|B<-b> I<start time>]>
S<[B<--step>|B<-s> I<step>]>
S<[B<DS:>I<ds-name>B<:>I<DST>B<:>I<dst arguments>]>
-I<heartbeat>B<:>I<min>B<:>I<max>]>
S<[B<RRA:>I<CF>B<:>I<cf arguments>]>
=head1 DESCRIPTION
I<seasonal period> arguments agree.
I<alpha> is the adaption parameter of the intercept (or baseline)
-coefficient in the Holt-Winters forecasting algorithm. See L<RRDtool> for a
+coefficient in the Holt-Winters forecasting algorithm. See L<rrdtool> for a
description of this algorithm. I<alpha> must lie between 0 and 1. A value
closer to 1 means that more recent observations carry greater weight in
predicting the baseline component of the forecast. A value closer to 0 mean