M-File Programming (Programming and Data Types)

Programming and Data Types

Special Values

Several functions return important special values that you can use in your M-files.

Function
Return Value

ans
Most recent answer (variable). If you do not assign an output variable to an expression, MATLAB automatically stores the result in ans.

eps
Floating-point relative accuracy. This is the tolerance MATLAB uses in its calculations.

realmax
Largest floating-point number your computer can represent.

realmin
Smallest floating-point number your computer can represent.

pi
3.1415926535897...

i, j
Imaginary unit.

inf
Infinity. Calculations like n/0, where n is any nonzero real value, result in inf.

NaN
Not-a-Number, an invalid numeric value. Expressions like 0/0 and inf/inf result in a NaN, as do arithmetic operations involving a NaN. n/0, where n is complex, also returns NaN.

computer
Computer type.

version
MATLAB version string.

Function	Return Value
`ans`	Most recent answer (variable). If you do not assign an output variable to an expression, MATLAB automatically stores the result in `ans`.
`eps`	Floating-point relative accuracy. This is the tolerance MATLAB uses in its calculations.
`realmax`	Largest floating-point number your computer can represent.
`realmin`	Smallest floating-point number your computer can represent.
`pi`	`3.1415926535897...`
`i`, `j`	Imaginary unit.
`inf`	Infinity. Calculations like `n/0`, where `n` is any nonzero real value, result in `inf`.
`NaN`	Not-a-Number, an invalid numeric value. Expressions like `0/0` and `inf/inf` result in a `NaN`, as do arithmetic operations involving a `NaN`. `n/0`, where `n` is complex, also returns `NaN`.
`computer`	Computer type.
`version`	MATLAB version string.

Here are several examples that use these values in MATLAB expressions.

x = 2*pi;
A = [3+2i 7-8i];
tol = 3*eps;

Persistent Variables Data Types