数值分析－列选主元求解方程组

//n 整型变量。方程组的阶数

//a 双精度实型二维数组，体积为n*n。存放方程组的系数矩阵，返回时将被破坏。

//b 双精度实型一维数组，长度为n，存放方程组右端的常数向量；返回方程组的解向量。

//本函数返回整型标志值。若返回的标志值为0,则表示原方程组的系数矩阵奇异，输出信息“fail”；若返回的标志值不为0,则表示正常返回。-Numerical Analysis-out election PCA solving equations / / n integer variables. Equations of bands / / a double precision real-dimensional array, the volume of n * n. The storage equation coefficient matrix, the return would be compromised. / / B double precision real-one-dimensional arrays, length n, storage equations subguadratic constant vector; Return to the solution of the equations vector. / / This function returns integer values signs. If the return value of 0 signs, the group said the original equation coefficient matrix, the output information "fail"; if the return value is not a sign of 0, then return to normal.