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Eigen 这么强大的库竟然没有移位的功能 ,哎
手写一个
/*循环移位 a、b 绝对值大小要小于 data 的行列数
a b 为正数时 向下移动a行 ,向右移动b 列
*/
MatrixXd circshift(MatrixXd data,int a, int b = 0)
{
UINT row = data.rows();
UINT col = data.cols();
MatrixXd out(row, col);
MatrixXd y(row, col);
if (a > 0)//向下移动a行
{
out.topRows(a)=data.bottomRows(a);
out.bottomRows(row - a) = data.topRows(row - a);
}
if (a < 0)//向上移动a行
{
out.topRows(row + a) = data.bottomRows(row + a);
out.bottomRows(abs(a)) = data.topRows(abs(a));
}
if (a == 0)
{
out.array() = data.array();
}
if (b > 0)//向右移动b列
{
y.leftCols(b) = out.rightCols(b);
y.rightCols(col - b) = out.leftCols(col - b);
}
if(b<0)//向左移动b列
{
y.leftCols(col + b) = out.rightCols(col + b);
y.rightCols(abs(b)) = out.leftCols(abs(b));
}
if (b ==0)
{
y = out;
}
return y;
}
测试代码
MatrixXd data(3, 3);
data << 1, 2, 3,
4, 5, 6,
7, 8, 9;
cout << "原始矩阵\n" <<data<< endl;
cout << "向左移动1次\n" << circshift(data,0, -1) << endl;
cout << "向右移动2次\n" << circshift(data, 0, 2) << endl;
cout << "向下移动2次 向左移动1次\n" << circshift(data, 2,-1) << endl;
cout << "向上移动一次\n" << circshift(data, -1) << endl;