Question

如何用Matlab求解方程组

Answer 1

参考现代数值计算

也可以直接用 x = a \ b;
function x = gauss_matric(a,b); %高斯消元法(列主消元)
A = [a b];
[r c] = size(A);
for i = 1 : r-1
[~, A_max] = max(abs(A(i:r,i)));
A_tmp = A(i,:);
A(i,:) = A(A_max+i-1,:);
A(A_max+i-1,:) = A_tmp;
for j = i+1 : r
A(j,:) = A(j,:)-A(i,:)/A(i,i)*A(j,i);
end
end
for i = r : -1 : 1
x_tmp = 0;
for j = r : -1 : i + 1
x_tmp = x_tmp + A(i,j)*x(j);
end
x(i) = (A(i,c)-x_tmp)/A(i,i);
end
end

除了以上还有 LU、QR等等方法