[x y z bx by bz] = textread('sep_0nl.lis','%f %f %f %f %f %f', 'headerlines', 13);
[nx ny nz] = textread('sep_0nl.lis','%*s %*s %*s %*s %u %u %u', 1, 'headerlines', 10);


Bx = reshape(bx,nx,ny,nz);
By = reshape(by,nx,ny,nz);
Bz = reshape(bz,nx,ny,nz);

x1 = reshape(x,nx,ny,nz);
y1 = reshape(y,nx,ny,nz);
z1 = reshape(z,nx,ny,nz);

i=1:32;
test = [x1(i);y1(i);z1(i)]'

%min(x) max(x)

sx = max(diff(x)); % read step size along x
sy = max(diff(y)); % read step size along y
sz = max(diff(z)); % read step size along z

x2 = -x(end:-1:1);
x3 = -x(end:-1:1);
x4 = -x(end:-1:1);

x2 = reshape(x2,nx,ny,nz);
x3 = reshape(x3,nx,ny,nz);
x4 = reshape(x4,nx,ny,nz);

%p = [x(:)'; y(:)'; z(:)']; 
%ind2sub
%[i j] = ind2sub(3,x1);