MATLAB的5种取整操作总结

floor：向负无穷方向取整

如：floor(-1.1) = -2; floor(1.9) = 1; floor(1.1) = 1; floor(-1.9) = -2

ceil：向正无穷方向取整

如：ceil(-1.1) = -1; ceil(1.9) = 2; ceil(1.1) = 2; ceil(-1.9) = -1

fix：向零方向取整，即正数和负数都向零方向靠拢

如：fix(-1.1) = -1; fix(1.9) = 1; fix(1.1) = 1; fix(-1.9) = -1

round：四舍五入到最近的整数，0.5进位，0.49舍去

如：round(-1.1) = -1; round(1.5) = 2; round(1.1) = 1; round(-1.5) = -2

nearest：相对round，唯一区别是将负0.5舍去

如：nearest(-1.1) = -1; nearest(1.5) = 2; nearest(1.1) = 1; nearest(-1.5) = -1

(1) nearest相比round操作，实现更简单，但可能引入固定偏差带来直流问题

(2) 也称为伪round。nearest(x) = floor(x+0.5)。