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# NAG Toolbox: nag_machine_precision (x02aj)

## Purpose

nag_machine_precision (x02aj) returns ε$\epsilon$, the value machine precision.

## Syntax

[result] = x02aj
[result] = nag_machine_precision

## Description

nag_machine_precision (x02aj) returns machine precision, computed as ε = (1/2) × b1p $\epsilon =\frac{1}{2}×{b}^{1-p}$, where b$b$ is the arithmetic base (see nag_machine_model_base (x02bh)) and p$p$ is the number of significant base-b$b$ digits (see nag_machine_model_digits (x02bj)).
It is important to note that the definition of ε$\epsilon$ here differs from that in ISO (1997).

## References

ISO (1997) ISO Fortran 95 programming language (ISO/IEC 1539–1:1997)

## Parameters

None.

None.

None.

### Output Parameters

1:     result – double scalar
The result of the function.

None.

None.

None.

## Example

```function nag_machine_precision_example
[result] = nag_machine_precision
```
```

result =

1.1102e-16

```
```function x02aj_example
[result] = x02aj
```
```

result =

1.1102e-16

```

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Chapter Contents
Chapter Introduction
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