%---------------------------------------------------------------function  [w,dwdx,dwdy] = cubwgt(dif,t,v,dmax,dm)% CUBIC SPLINE WEIGHT FUNCTIONl = length(v);for i=1:ldrdx = sign(dif(1,i))/dm(1,v(i));drdy = sign(dif(2,i))/dm(2,v(i));rx = abs(dif(1,i))/dm(1,v(i));ry = abs(dif(2,i))/dm(2,v(i));if rx>0.5  wx = (4/3)-4*rx+4*rx*rx -(4/3)*rx^3;  dwx = (-4 + 8*rx-4*rx^2)*drdx;elseif rx<=0.5  wx = (2/3) - 4*rx*rx + 4*rx^3;  dwx = (-8*rx + 12*rx^2)*drdx;endif ry>0.5  wy = (4/3)-4*ry+4*ry*ry -(4/3)*ry^3;  dwy = (-4 + 8*ry-4*ry^2)*drdy;elseif ry<=0.5  wy = (2/3) - 4*ry*ry + 4*ry^3;  dwy = (-8*ry + 12*ry^2)*drdy;endw(i) = wx*wy;dwdx(i) = wy*dwx;dwdy(i) = wx*dwy;end