1、fix-向零方向取整。
fix Round towards zero.
fix(X) rounds the elements of X to the nearest integers
towards zero.
2、fix使用举例：
t =
7.6806 3.5388 3.6130 9.0150 8.1769 3.1781
2.3309 3.4719 7.4163 3.1834 9.8118 9.8445
5.8736 2.5372 7.0590 5.9708 8.6199 5.4825
4.5897 9.5253 7.0089 2.9780 0.8382 7.4925
8.6098 2.9820 0.0623 1.2501 3.3771 8.4185
6.6084 1.5841 3.7435 3.8836 2.3613 1.6689
-----------------------------------------------------------------------
fix(t)
ans =
7 3 3 9 8 3
2 3 7 3 9 9
5 2 7 5 8 5
4 9 7 2 0 7
8 2 0 1 3 8
6 1 3 3 2 1
3、round-向最近的方向取整。
round Round towards nearest integer.
round(X) rounds the elements of X to the nearest integers.
4、floor-向负无穷大方向取整：
floor Round towards minus infinity.
floor(X) rounds the elements of X to the nearest integers
towards minus infinity.
5、ceil-向正无穷大方向取整。
ceil Round towards plus infinity.
ceil(X) rounds the elements of X to the nearest integers
towards infinity.
6、mod-计算模数：
mod Modulus after division.
mod(x,y) is x - n.*y where n = floor(x./y) if y ~= 0. If y is not an
integer and the quotient x./y is within roundoff error of an integer,
then n is that integer. The inputs x and y must be real arrays of the
same size, or real scalars.
The statement "x and y are congruent mod m" means mod(x,m) == mod(y,m).
By convention:
mod(x,0) is x.
mod(x,x) is 0.
mod(x,y), for x~=y and y~=0, has the same sign as y.
Note: REM(x,y), for x~=y and y~=0, has the same sign as x.
mod(x,y) and REM(x,y) are equal if x and y have the same sign, but
differ by y if x and y have different signs.
