@BeginModule
@NewPage
@Name      = Seaspctl
@Title     = Seasonal percentile values
@Section   = Statistical values
@Class     = Statistic
@Arguments = ifile1 ifile2 ifile3 ofile
@Operators = seaspctl

@BeginDescription
This operator computes percentiles over all timesteps in @file{ifile1} of the same season.
The algorithm uses histograms with minimum and maximum bounds given in @file{ifile2} and @file{ifile3},
respectively. The default number of histogram bins is 101. The default can be overridden by setting 
the environment variable @env{CDO_PCTL_NBINS} to a different value. The files @file{ifile2} and 
@file{ifile3} should be the result of corresponding @mod{seasmin} and @mod{seasmax} operations, respectively.
The time stamp in @file{ofile} is from the middle contributing timestep of @file{ifile1}.
Be careful about the first and the last output timestep, they may be incorrect values 
if the seasons have incomplete timesteps.
@EndDescription
@EndModule


@BeginOperator_seaspctl
@Title     = Seasonal percentiles
@Parameter = p

@BeginDescription
@IfMan
For every adjacent sequence t_1, ...,t_n of timesteps of the same season it is

o(t,x) = pth percentile {i(t',x), t1 < t' <= tn}
@EndifMan
@IfDoc
\vspace*{1mm}
For every adjacent sequence \begin{math}t_1, ...,t_n\end{math} of timesteps of 
the same season it is: \\
\vspace*{1mm}

@BeginMath
o(t,x) = \mbox{\bf pth percentile}\{i(t',x), t_1 < t' \le t_n\}
@EndMath
@EndifDoc
@EndDescription
@EndOperator


@BeginParameter
@Item = p
FLOAT  Percentile number in {0, ..., 100}
@EndParameter


@BeginEnvironment
@Item = CDO_PCTL_NBINS
Sets the number of histogram bins. The default number is 101.
@EndEnvironment


@BeginExample
To compute the seasonal 90th percentile of a time series use:
@BeginVerbatim
   cdo seasmin ifile minfile
   cdo seasmax ifile maxfile
   cdo seaspctl,90 ifile minfile maxfile ofile
@EndVerbatim
Or shorter using operator piping:
@BeginVerbatim
   cdo seaspctl,90 ifile -seasmin ifile -seasmax ifile ofile
@EndVerbatim
@EndExample
