samer@4: function M=expmap(p1,p2,p3)
samer@4: % expmap - Create exponentially spaced discretisation map
samer@4: %
samer@4: % expmap :: Min:real, Max:real, N:natural -> dmap(N).
samer@4: % expmap :: [Min,Max]:[[1,2]], N:natural -> dmap(N).
samer@4: %
samer@4: % Parameters work almost but not quite like logspace: the
samer@4: % third parameter is the number of GAPS, not the number of
samer@4: % points, defining the map, So for a map with edges at 0:10,
samer@4: % use linmap(0,10,10). To get the same edges from linspace,
samer@4: % you would need linspace(0,10,11).
samer@4: 
samer@4: % unpack parameters
samer@4: if nargin==2, min=log(p1(1)); max=log(p1(2)); bins=p2;
samer@4: else min=log(p1); max=log(p2); bins=p3; end
samer@4: 
samer@4: dx=(max-min)/bins;
samer@4: M=dmap(bins,@(t)map(bins,min,1/dx,t),@(t)revmap(min,dx,t));
samer@4: 
samer@4: function I=map(N,min,k,X)
samer@4: 	U=log(X);
samer@4: 	I=1+floor(k*(U-min));
samer@4: 	I(I<1)=-inf;
samer@4: 	I(I>N)=inf;
samer@4: 
samer@4: function X=revmap(min,ik,I)
samer@4: 	I=shiftdim(shiftdim(I),-1);
samer@4: 	U1=min+(I-1)*ik;
samer@4: 	U2=min+(I)*ik;
samer@4: 	X=exp(cat(1,U1,U2));
samer@4: