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Re: [ferret_users] median averager, not a smoother
Building on this suggestion, it'd be even better to have a "quantile
transformation," e.g.
variable[t=@QNT:.5]
would return the temporal median and
variable[t=@QNT:.9]
would return the temporal 90th percentile.
Here's a sample script showing one way to do the quantile interpolation
for a 1-dimensional time-oriented variable:
! Usage: go quantile variable_1d [quantile var_out]
! $1 [ $2 $3 ]
! Return a quantile of a one-dimensional variable.
! The quantile value is interpolated if necessary.
! Default is the median (0.5 quantile).
let q_idx = 1 + $2".5" * (`$1,r=lend`-1)
let q_sort = samplel($1,sortl(($1)))
let q_val = q_sort[t=`q_idx`]
let $3"quantile" = `q_val`
Andrew
David Wang wrote:
Dear Ferret developers,
I appreciate the recent, useful addition of median transformation
smoother @MED into Ferret. Sometimes, however, I find myself (probably
others as well) in need of a median averager, much like @AVE as an
arithmetic averager. For instance, I'd like to get the median of a time
series and use the resultant scalar in other expressions. I wonder if
such a transformation could be implemented into future Ferret release.
Thanks,
David
--
turn and live.
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