双线性插值函数为
u(x,y)=a +bx+cy+dxy
u(0,0)=a=1-->a=1
u(0,1)=a+c=3-->c=2
u(1,0)=a+b=2-->b=1
u(1,1)=a+b+c+d=5-->d=1
u(x,y)=1+x+2y+xy
坐标为(0.2,0.4)该点处u(0.2,0.4)=1+0.2+2*0.4+0.2*0.4=2.08
双线性插值函数为
u(x,y)=a +bx+cy+dxy
u(0,0)=a=1-->a=1
u(0,1)=a+c=3-->c=2
u(1,0)=a+b=2-->b=1
u(1,1)=a+b+c+d=5-->d=1
u(x,y)=1+x+2y+xy
坐标为(0.2,0.4)该点处u(0.2,0.4)=1+0.2+2*0.4+0.2*0.4=2.08