Mathematics

Data Type single

To assign the data type single to a numbers or variable, use the command single. For example,

• a = single(5)
  

sets the value of a to be 5 with data type single.

Storing a number as type single require only half as much memory as storing it as type double. You can compare how many bytes of memory are used to store 5 as type single versus type double using the whos command.

• b = 5;
  whos
    Name      Size                   Bytes  Class
  
    a         1x1                        4  single array
    b         1x1                        8  double array
  

When you convert a number of type double to type single, MATLAB rounds the number to the nearest single-precision number. This can change the stored value slightly. For example,

• format long
  single(3.14)
  ans =
  
     3.1400001
  

You can return an upper bound for how much the stored value of a number changes when you convert it to single using the eps command, as described in The Function eps.

Single-Precision Mathematics

Single-Precision Arithmetic

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