Usually modulo operation is also called remainder operation, and both return the remainder as their result..remandmodThe only difference is:

When x and y have the same sign, the results of the two functions are identical; when x and y have different signs, the sign of the rem function result is the same as x, while mod follows y.

This is because the two functions have different generation mechanisms: rem uses the fix function, while mod uses the floor function (these two functions are used for rounding; fix rounds toward 0, and floor rounds toward negative infinity). The rem(x, y) command returns x - n.*y. If y is not equal to 0, where n = fix(x./y). And mod(x, y) returns x - n.*y; when y is not equal to 0, n = floor(x./y).

The value pattern for modulo of two integers with opposite signs (the same rule applies to decimals; this seems different from the C language)

First treat both integers as positive numbers, then perform division:

• 1. When divisible, the value is 0
• 2. When not divisible, value = divisor × (integer quotient + 1) - dividend

Example:mod(36,-10)=-4

That is: 36 divided by 10 gives integer quotient 3, plus 1 gives 4; its product with the divisor is 40; then the difference from the dividend is (40-36=4); take the sign of the divisor. So the value is -4.

Example: mod(9,1.2)=0.6;

Example:

>> mod(5,2)
ans =1                   % 除数是正，余数就是正
>> mod(-5,2)
ans =1
>> mod(5,-2)
ans =-1                  % 除数是负，余数就是负
>> mod(-5,-2)
ans =-1                  % 用 rem 时，不管除数是正是负，余数的符号与被除数的符号相同
>> rem(5,2)
ans =1                   % 被除数是正，余数就是正
>> rem(5,-2); 
ans =1
>> rem(-5,2)
ans =-1                 % 被除数是负， 余数就是负
>> rem(-5,-2)
ans =-1

Take your time to understand; they are indeed different.