NAG Library Function Document

nag_random_discrete_uniform (g05dyc)

+− Contents

1 Purpose

2 Specification

3 Description

4 References

5 Arguments

6 Error Indicators and Warnings

7 Accuracy

8 Further Comments

+− 9 Example

9.1 Program Text

9.2 Program Data

9.3 Program Results

1 Purpose

nag_random_discrete_uniform (g05dyc) returns a pseudorandom integer taken from a uniform distribution over the interval

[m, n]

2 Specification

#include <nag.h>

#include <nagg05.h>

Integer

nag_random_discrete_uniform (Integer m, Integer n)

3 Description

The distribution of a uniform random variable,

I

, is given by

\begin{array}{l} P (I = i) = \frac{1}{n - m + 1} & if m \leq i \leq n \\ P (I = i) = 0 & otherwise ​ \end{array}

assuming

m \leq n

. The function returns the value

m + [(n - m + 1) y]

where [ ] denotes the integer part, and

y

is a pseudorandom number from a uniform distribution over (0,1), generated by nag_random_continuous_uniform (g05cac). If

m > n

, the roles of

m

and

n

are reversed.

4 References

Knuth D E (1981) The Art of Computer Programming (Volume 2) (2nd Edition) Addison–Wesley

5 Arguments

1: m – IntegerInput
2: n – IntegerInput: On entry: the end-points $m$ and $n$ of the distribution. It is not necessary that $m < n$ .

6 Error Indicators and Warnings

None.

7 Accuracy

Not applicable.

8 Further Comments

None.

9 Example

The example program prints the first five pseudorandom integers from a uniform distribution between -5 and 5, generated by nag_random_discrete_uniform (g05dyc) after initialization by nag_random_init_repeatable (g05cbc).

9.1 Program Text

Program Text (g05dyce.c)

9.2 Program Data

None.

9.3 Program Results

Program Results (g05dyce.r)

nag_random_discrete_uniform (g05dyc) (PDF version)

g05 Chapter Contents

g05 Chapter Introduction

NAG C Library Manual

NAG Library Function Documentnag_random_discrete_uniform (g05dyc)

+− Contents

1 Purpose

2 Specification

3 Description

4 References

5 Arguments

6 Error Indicators and Warnings

7 Accuracy

8 Further Comments

9 Example

9.1 Program Text

9.2 Program Data

9.3 Program Results

NAG Library Function Document

nag_random_discrete_uniform (g05dyc)