How to Round toward negative infinity in MATLAB

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