矩阵三角化导致错误类型参数对一元减去

Question

我有这个方法返回矩阵三角化例程中使用的值

 float **trian(int n, float **Xy)
    {
        int i,row,col;
        float **sign = 1;
        for ( i = 0; i < n; i++) {
            int max = 0;

            for ( row = i; row < n; row++)
                if (fabs(Xy[row][i]) > fabs(Xy[max][i]))
                    max = row;

            if (max) {
                sign = -sign;
                float *tmp = Xy[i];
                Xy[i] = Xy[max], Xy[max] = tmp;
            }

            if (!Xy[i][i]) return 0;
            row=0;
            for (row = i + 1; row < n; row++) {
                float r = Xy[row][i] / Xy[i][i];
                if (!r) continue;

                for ( col = i; col < n; col ++)
                    Xy[row][col] -= Xy[i][col] * r;
            }
        }
        return sign;
    }

不幸的是得到这个错误

main.c:74:20: error: wrong type argument to unary minus

错误行

 sign = -sign;

Answer 1

这里出了点问题：

float **sign = 1;
....
sign = -sign;

您的意思是使用**sign代替sign吗？

---

也许你只需要这样的东西：

int trian(int n, float **Xy) {
  ...
  int sign = 1;
  ...
  sign = -sign;
  ...
  return sign;
}