GNU Octave Manual Version 3by John W. Eaton, David Bateman, Søren Hauberg Paperback (6"x9"), 568 pages ISBN 095461206X RRP £24.95 ($39.95) |

## 17.7 Mathematical Constants

__Built-in Function:__**I***(*`x`)__Built-in Function:__**I***(*`n`,`m`)__Built-in Function:__**I***(*`n`,`m`,`k`, ...)__Built-in Function:__**I***(...,*`class`)- Return a matrix or N-dimensional array whose elements are all equal
to the pure imaginary unit, defined as
`sqrt (-1)`

.Since I (also i, J, and j) is a function, you can use the name(s) for other purposes.

__Built-in Function:__**Inf***(*`x`)__Built-in Function:__**Inf***(*`n`,`m`)__Built-in Function:__**Inf***(*`n`,`m`,`k`, ...)__Built-in Function:__**Inf***(...,*`class`)- Return a matrix or N-dimensional array whose elements are all Infinity.
The arguments are handled the same as the arguments for
`eye`

. The optional argument`class`may be either`‘"single"’`or`‘"double"’`. The default is`‘"double"’`.

__Built-in Function:__**NaN***(*`x`)__Built-in Function:__**NaN***(*`n`,`m`)__Built-in Function:__**NaN***(*`n`,`m`,`k`, ...)__Built-in Function:__**NaN***(...,*`class`)- Return a matrix or N-dimensional array whose elements are all NaN
(Not a Number). The value NaN is the result of an operation like
0/0, or
`‘Inf - Inf’`,or any operation with a NaN.

Note that NaN always compares not equal to NaN. This behavior is specified by the IEEE standard for floating point arithmetic. To find NaN values, you must use the

`isnan`

function.The arguments are handled the same as the arguments for

`eye`

. The optional argument`class`may be either`‘"single"’`or`‘"double"’`. The default is`‘"double"’`.

__Built-in Function:__**pi***(*`x`)__Built-in Function:__**pi***(*`n`,`m`)__Built-in Function:__**pi***(*`n`,`m`,`k`, ...)__Built-in Function:__**pi***(...,*`class`)- Return a matrix or N-dimensional array whose elements are all equal
to the ratio of the circumference of a circle to its diameter.
Internally,
`pi`

is computed as`‘4.0 * atan (1.0)’`.

__Built-in Function:__**e***(*`x`)__Built-in Function:__**e***(*`n`,`m`)__Built-in Function:__**e***(*`n`,`m`,`k`, ...)__Built-in Function:__**e***(...,*`class`)- Return a matrix or N-dimensional array whose elements are all equal
to the base of natural logarithms. The constant
`e`satisfies the equation

`log`

(`e`) = 1.

__Built-in Function:__**eps***(*`x`)__Built-in Function:__**eps***(*`n`,`m`)__Built-in Function:__**eps***(*`n`,`m`,`k`, ...)__Built-in Function:__**eps***(...,*`class`)- Return a matrix or N-dimensional array whose elements are all eps,
the machine precision. More precisely,
`eps`

is the largest relative spacing between any two adjacent numbers in the machine's floating point system. This number is obviously system-dependent. On machines that support 64-bit IEEE floating point arithmetic,`eps`

is approximately 2.2204e-16.

__Built-in Function:__**realmax***(*`x`)__Built-in Function:__**realmax***(*`n`,`m`)__Built-in Function:__**realmax***(*`n`,`m`,`k`, ...)__Built-in Function:__**realmax***(...,*`class`)- Return a matrix or N-dimensional array whose elements are all equal
to the largest floating point number that is representable. The actual
value is system-dependent. On machines that support 64-bit IEEE
floating point arithmetic,
`realmax`

is approximately 1.7977e+308See also realmin

__Built-in Function:__**realmin***(*`x`)__Built-in Function:__**realmin***(*`n`,`m`)__Built-in Function:__**realmin***(*`n`,`m`,`k`, ...)__Built-in Function:__**realmin***(...,*`class`)- Return a matrix or N-dimensional array whose elements are all equal
to the smallest normalized floating point number that is representable.
The actual value is system-dependent. On machines that support
64-bit IEEE floating point arithmetic,
`realmin`

is approximately 2.2251e-308See also realmax

ISBN 095461206X | GNU Octave Manual Version 3 | See the print edition |