%下面对表格中的数据进行线性插值函数
function y = linear_cha(CX,X,Y)
[m,n]=size(CX);
ma = 0.1:0.1:0.9;alpha = 0:2:10;
%寻找横坐标
% for i = 1:8
for i = 1:n-1
% if (ma(i)<X)&&(ma(i+1)>=X)
if (ma(i)<=X)&&(ma(i+1)>=X)
X_ = ma(i);
index_i = i;
break;
end
end
%寻找纵坐标
% for i = 1:5
for i = 1:m-1
if (alpha(i)<Y)&&(alpha(i+1)>=Y)
Y_ = alpha(i);
index_j = i;
break;
end
end
x1 = ma(index_i);y1 = alpha(index_j);
x2 = ma(index_i);y2 = alpha(index_j + 1);
x3 = ma(index_i + 1);y3 = alpha(index_j + 1);
x4 = ma(index_i + 1);y4 = alpha(index_j);
%构造多项式矩阵求解系数
A = [1 x1 y1 x1*y1;...
1 x2 y2 x2*y2;...
1 x3 y3 x3*y3;...
1 x4 y4 x4*y4];
b = [CX(index_j,index_i);...
CX(index_j+1,index_i);...
CX(index_j+1,index_i+1);...
CX(index_j,index_i+1)];
x = A\b;
y = x'*[1;X;Y;X*Y];
end
