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# How to Round toward negative infinity in MATLAB

• Last Updated : 06 Jul, 2021

Rounding a number towards infinity means rounding the number X to the nearest integer less than or equal to X. In this article, we will discuss how to round toward negative infinity in MATLAB.

### Example:

Suppose X = 3.5, then result is 3
And if X = -3.5, then result is -4

The floor() function in MATLAB can be leveraged to round the number towards negative infinity. Different syntaxes of floor() function in Matlab are

• Y = floor(val)
• Y = floor(X)
• Y = floor(t)
• Y = floor(t,unit)

Now we will discuss the syntaxes of the above function:

### Y = floor(val):

• Rounds the element val to the nearest integer less than or equal to val.

## Matlab

 `% Input vector``% Input vector``val = -3.1;` `% Rounding the elements in vector``Y = floor(val);` `% Printing the rounded vector``disp(Y)`

Output :

`-4`

### Y = floor(X):

• The function takes input as a vector of elements X.
• Returns the vector by rounding each element in X toward negative infinity.

## Matlab

 `% Input vector``% Input vector``X = [-1.2  -0.2  -4.4  7.6  -12.0];` `% Rounding the elements in vector``Y = floor(X)` `% Printing the rounded vector``disp(Y)`

Output :

`-2    -1    -5     7   -12`

### Y = floor(t):

• Here t is an array of duration in “hh:mm:ss:SS”
• hh: Hours
• mm: Minutes
• ss: Seconds
• SS: Milliseconds
• Rounds every element of array t to its nearest number of seconds less than or equal to the element.

## Matlab

 `% Array of duration``t = hours(5) + minutes(2:4) + seconds(1.78);` `%  Format the array into time format``t.Format = ``'hh:mm:ss.SS'``;` `% Display initial duration array``disp(``"duration :"``)``disp(t);` `% Rounding the duration array``Y1 = floor(t);``disp(``"Rounded duration :"``);``disp(Y1);`

Output :

```duration :
05:02:01.78   05:03:01.78   05:04:01.78

Rounded duration :
05:02:01.00   05:03:01.00   05:04:01.00```

### Y = floor(t,unit):

• Here t is the duration array where every element in the format of “hh:mm:ss:SS”
• Rounds each element of t to the nearest number of the specified unit of time less than or equal to that element.
• Unit of time can be ‘seconds’, ‘minutes’, ‘hours’, ‘days’, or ‘years’.
• The default value of unit is ‘seconds’.

## Matlab

 `% Array of duration``t = hours(5) + minutes(2:4) + seconds(1.78);` `%  Format the array into time format``t.Format = ``'hh:mm:ss.SS'``;` `% Display initial duration array``disp(``"duration :"``)``disp(t);` `% Rounding the duration array to the nearest minutes``% less than or equal to element``Y1 = floor(t,``'minutes'``);``disp(``"Rounded duration :"``);``disp(Y1);`

Output :

```duration :
05:02:01.78   05:03:01.78   05:04:01.78

Rounded duration :
05:02:00.00   05:03:00.00   05:04:00.00```

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