samer@4: function z=linterp_d(k,z0,d)
samer@4: % linterp_d - linear interpolation between two points
samer@4: %
samer@4: % linterp_d :: 
samer@4: %    real   ~'fraction of distance to travel from from initial to final point',
samer@4: %    [Size] ~'initial point',
samer@4: %    [Size] ~'vector from initial to final point'
samer@4: % -> [Size] ~'interpolated point'.
samer@4: %
samer@4: % Definition is linterp_d(k,z0,d) = linterp(k,z0,z0+d)
samer@4: %
samer@4: % See also: LINTERP, VLINTERP
samer@4: 
samer@4: z = z0+k.*d;