VFILT is the jVarfun module of jLab.

 VFILT  Filtering along rows without change in length.
 
    Y=VFILT(X,FILTER) convolves FILTER with X along their rows and crops 
    the result Y to be the same length as X. If FILTER is a number, a 
    Hanning filter of that length is used.  
                                                                          
    [Y1,Y2,...YN]=VFILT(X1,X2,...XN,FILTER) also works.
 
    The input arrays XI may have any dimensionality.
 
    VFILT(X1,X2,...XN,FILTER); with no output arguments overwrites the
    original input variables.
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    Median filter
 
    VFILT can also be used to implement a sliding-window median filter.
 
    Y=VFILT(...,N,'median') returns the median in a window of length N
    centered on the current point.  If N is even, N+1 is used for the
    window length.  Y will be the same length as X.
    
    The median filter is sensibly defined with an implicit "boxcar" filter. 
    VFILT(...,FILTER,'median') with some other filter input will therefore
    use a sliding window of length LENGTH(FILTER), ignoring FILTER itself.
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    Boundary conditions
 
    Y=VFILT(..., STR), where STR is a string, optionally specifies
    the boundary condition to be imposed at the edges of the time
    series.  Valid options for STR are 
 
          STR = 'zeros' or 'nonans' for zero-padding beyond endpoints 
          STR = 'nan' for zero-padding beyond the endpoints, setting 
                 contaminated points near the edges to NaNs
          STR = 'periodic' for periodic boundary conditions 
          STR = 'mirror' for reflecting the time series at both ends
 
    By default, STR='nan', implying that the roughly length(FILTER)/2 
    data points on each end of Y which are contaminated by edge effects
    are replaced with NANs.
 
    All boundary conditions take into account potential blocks of 
    missing data, marked by NaNs, at beginning and end of each column.  
    ___________________________________________________________________
 
   'vfilt --t' runs a test.
 
    Usage: y=vfilt(x,filter);
           y=vfilt(x,filter,'zeros');
           y=vfilt(x,N,'median','zeros');
           [y1,y2,y3]=vfilt(x1,x2,x3,filter);
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    This is part of JLAB --- type 'help jlab' for more information
    (C) 2000--2014 J.M. Lilly --- type 'help jlab_license' for details