全选主元Gauss-Jordan消去法求解线性代数方程组。其中a是方程组系数矩阵，b先存右端的m组常数向量，之后存解向量。n是阶数，m是右端常数向量组数。-Select the main element Gauss-Jordan Elimination method for solving linear algebraic equations. Where a is the coefficient matrix, b right side of m pre-existing group of constant vector, and then deposit solution vector. n is the order number, m is the number of right end of the constant vectors.