vfilt.m

JLAB is a set of Matlab functions I have written or co-written over the past fifteen years for the p

function[varargout]=vfilt(varargin)
%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.  
%                                                                         
%   By default, the roughly length(FILTER)/2 data points on each end
%   of Y that are contaminated by edge effects are replaced with NANs.
%   This option may be turned off with Y=VFILT(X,FILTER,'nonans').
%
%   [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.
%
%   'vfilt --t' runs a test.
%
%   Usage: y=vfilt(x,filter);
%          y=vfilt(x,filter,'nonans');
%          [y1,y2,y3]=vfilt(x1,x2,x3,filter);
%   __________________________________________________________________
%   This is part of JLAB --- type 'help jlab' for more information
%   (C) 2000--2005 J.M. Lilly --- type 'help jlab_license' for details    
 
%if strcmp(varargin{1}, '--t')
%  vfilt_test,return
%end

if strcmp(varargin{1},'--t')
    vfilt_test;return
end

narg=nargin;
bnan=1;
str='nan';
if ischar(varargin{end})
   str=lower(varargin{end});
   varargin=varargin(1:end-1);
   narg=narg-1;
end

% ndim=1;
% if length(varargin{end})==1
%    ndim=varargin{end};
%    varargin=varargin(1:end-1);
%    narg=narg-1;
% end

n=varargin{end};

for i=1:narg-1
    varargout{i}=vfilt1(varargin{i},n,str);
end
 
eval(to_overwrite(narg-1))

function[smooth]=vfilt1(data,filter,str)
if nargin==2, bnan=1;end

if length(filter)==1
	filter=hanning(filter);
    filter=filter./sum(filter);
end

smooth=zeros(size(data));
a=round(length(filter)/2);
N=size(data,1);
n=length(filter);

if N<=n
  warning(['Not enough rows to filter the data with a ' int2str(n) ' filter'])
end

if res(n/2)==0
   halfn=floor(n/2);
else 
   halfn=floor((n-1)/2);
end

sd=size(data);
data=reshape(data,[sd(1) prod(sd(2:end))]);

for i=1:size(data,2)
	temp=conv(data(:,i),filter);
	smooth(:,i)=temp(a:a+N-1);
	if strcmp(str(1:3),'nan')
		smooth(1:halfn,i)=nan*ones(halfn,1);
		smooth(N-halfn+1:N,i)=nan*ones(halfn,1);
	end
end

smooth=reshape(smooth,sd);

% sd=size(data)
% sdnew=[sd(1)+n sd(2:end)]
% 
% %Add zeros at end
% data(end+[1:n],:)=zeros([n sd(2:end)]);
% data=data(:);
% 
% smooth=conv(data,filter);
% size(smooth)
% smooth=reshape(smooth,sdnew);
% 
% smooth=smooth(a:a+N-1,:);
% if bnan
%         smooth(1:halfn,i)=nan*ones(halfn,1);
%         smooth(N-halfn+1:N,i)=nan*ones(halfn,1);
% end


function[]=vfilt_test
x =[0 0 1 1 0 0]';
y1=[0 1 2 2 1 0]';

bool=aresame(y1,vfilt(x,[1 1 1]','nonnans'));
reporttest('VFILT simple nonans', bool)

x =[0 0 1 1 0 0]';
y1=[nan 1 2 2 1 nan]';

bool=aresame(y1,vfilt(x,[1 1 1]'));
reporttest('VFILT simple nans', bool)


x(:,:,1)=[0 0 1 1 0 0]';
x(:,:,3)=[0 0 1 1 0 0]';
y1(:,:,1)=[0 1 2 2 1 0]';
y1(:,:,3)=[0 1 2 2 1 0]';

bool=aresame(y1,vfilt(x,[1 1 1]','nonnans'));
reporttest('VFILT 3-D matrix', bool)