求助 提示秩不足

syms fn1 fn2 fn3 fn4 f1 f2 f3 f4 f m m1 m2 m3 m4 a1 a2 a3 a4 b1 b2 b3 b4 mz ;
f=f1+f2+f3+f4;
m1=mz+f1*(b1-a1)+f2*(b2-a1)+f3*(b3-a1)+f4*(b4-a1);
m2=mz+f1*(b1-a2)+f2*(b2-a2)+f3*(b3-a2)+f4*(b4-a2);
m3=mz+f1*(b1-a3)+f2*(b2-a3)+f3*(b3-a3)+f4*(b4-a3);
m4=mz+f1*(b1-a4)+f2*(b2-a4)+f3*(b3-a4)+f4*(b4-a4);
A=[ 1,0,a2-a1,a3-a1,a4-a1;
1,a1-a2,0,a3-a2,a4-a2;
1,a1-a3,a2-a3,0,a4-a3;
1,a1-a4,a2-a4,a3-a4,0];
B=[m1;m2;m3;m4];
X=A\B;
运行之后显示
警告: The system is rank-deficient. Solution is not unique.
> In F:\MATLAB2014B\toolbox\symbolic\symbolic\symengine.p>symengine at 56
In sym.sym>sym.privBinaryOp at 835
In sym.sym>sym.mldivide at 284
In c2 at 12
请大神看看怎么解决这个问题？