matlab_class/gcmfaces_calc/gcmfaces_interp_1d.m

function [Vq]=gcmfaces_interp_1d(xDim,X,V,Xq,varargin);
%[val]=gcmfaces_interp_1d(xDim,X,fld,Xq,varargin);
%object:    linearly interpolate field along xDim dimension
%           (>3 for gcmfaces objects)
%inputs:    xDim is the dimension along which to interpolate
%           X is the original position vector
%           V is a gcmfaces object with at least
%           Xq is the target position vector
%optional:  varargin ...
%outputs:   Vq is the interpolated field

gcmfaces_global;

%change format if needed
isagcmfaces=isa(V,'gcmfaces');
if isagcmfaces; V=convert2gcmfaces(V); end;

%move interpolation dimension to first
ndim=length(size(V));
tmp1=circshift([1:ndim],[0 1-xDim]);
V=permute(V,tmp1);
if size(X,1)==1; X=X'; end;
if size(Xq,1)==1; Xq=Xq'; end;

%the interpolation itself
Kq=interp1(X,[1:length(X)]',Xq,'linear');
Kqne=interp1(X,[1:length(X)]',Xq,'nearest','extrap');

%use bilinear; then extrapolate with nearest neighbor 
Vq=NaN*repmat(V(1,:,:),[length(Xq) 1 1]);
for kk=1:length(Xq);
    if ~isnan(Kq(kk));
        k0=floor(Kq(kk));
        k1=min(k0+1,length(X));
        a0=Kq(kk)-k0;
        tmp1=(1-a0)*V(k0,:,:)+a0*V(k1,:,:);
    else;
        tmp1=NaN*V(1,:,:);
    end;
    tmp2=V(Kqne(kk),:,:);
    tmp1(isnan(tmp1))=tmp2(isnan(tmp1));
    Vq(kk,:,:)=tmp1;
end;
    
%move interpolation dimension to first
ndim=length(size(Vq));
tmp1=circshift([1:ndim],[0 xDim-1]);
Vq=permute(Vq,tmp1);

%change format if needed
if isagcmfaces; Vq=convert2gcmfaces(Vq); end;

1	gforget	1.1	function [Vq]=gcmfaces_interp_1d(xDim,X,V,Xq,varargin);
2			%[val]=gcmfaces_interp_1d(xDim,X,fld,Xq,varargin);
3			%object: linearly interpolate field along xDim dimension
4			% (>3 for gcmfaces objects)
5			%inputs: xDim is the dimension along which to interpolate
6			% X is the original position vector
7			% V is a gcmfaces object with at least
8			% Xq is the target position vector
9			%optional: varargin ...
10			%outputs: Vq is the interpolated field
11
12			gcmfaces_global;
13
14			%change format if needed
15			isagcmfaces=isa(V,'gcmfaces');
16			if isagcmfaces; V=convert2gcmfaces(V); end;
17
18			%move interpolation dimension to first
19			ndim=length(size(V));
20			tmp1=circshift([1:ndim],[0 1-xDim]);
21			V=permute(V,tmp1);
22			if size(X,1)==1; X=X'; end;
23			if size(Xq,1)==1; Xq=Xq'; end;
24
25			%the interpolation itself
26			Kq=interp1(X,[1:length(X)]',Xq,'linear');
27			Kqne=interp1(X,[1:length(X)]',Xq,'nearest','extrap');
28
29			%use bilinear; then extrapolate with nearest neighbor
30			Vq=NaN*repmat(V(1,:,:),[length(Xq) 1 1]);
31			for kk=1:length(Xq);
32			if ~isnan(Kq(kk));
33			k0=floor(Kq(kk));
34			k1=min(k0+1,length(X));
35			a0=Kq(kk)-k0;
36			tmp1=(1-a0)V(k0,:,:)+a0V(k1,:,:);
37			else;
38			tmp1=NaN*V(1,:,:);
39			end;
40			tmp2=V(Kqne(kk),:,:);
41			tmp1(isnan(tmp1))=tmp2(isnan(tmp1));
42			Vq(kk,:,:)=tmp1;
43			end;
44
45			%move interpolation dimension to first
46			ndim=length(size(Vq));
47			tmp1=circshift([1:ndim],[0 xDim-1]);
48			Vq=permute(Vq,tmp1);
49
50			%change format if needed
51			if isagcmfaces; Vq=convert2gcmfaces(Vq); end;
52