g05 Chapter Contents
g05 Chapter Introduction
NAG Library Manual

# NAG Library Function Documentnag_rand_logical (g05tbc)

## 1  Purpose

nag_rand_logical (g05tbc) generates a vector of pseudorandom logical values – Nag_TRUE with probability $p$ and Nag_FALSE with probability $\left(1-p\right)$.

## 2  Specification

 #include #include
 void nag_rand_logical (Integer n, double p, Integer state[], Nag_Boolean x[], NagError *fail)

## 3  Description

nag_rand_logical (g05tbc) generates $n$ logical values ${x}_{i}$ from the relation
 $yi
where ${y}_{i}$ is a pseudorandom number from a uniform distribution over $\left(0,1\right]$, generated by nag_rand_basic (g05sac) using the values of state as input to this function.
One of the initialization functions nag_rand_init_repeatable (g05kfc) (for a repeatable sequence if computed sequentially) or nag_rand_init_nonrepeatable (g05kgc) (for a non-repeatable sequence) must be called prior to the first call to nag_rand_logical (g05tbc).

## 4  References

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

## 5  Arguments

1:     nIntegerInput
On entry: $n$, the number of pseudorandom logical values to be generated.
Constraint: ${\mathbf{n}}\ge 0$.
2:     pdoubleInput
On entry: must contain the probability of nag_rand_logical (g05tbc) returning Nag_TRUE.
Constraint: $0.0\le {\mathbf{p}}\le 1.0$.
3:     state[$\mathit{dim}$]IntegerCommunication Array
Note: the dimension, $\mathit{dim}$, of this array is dictated by the requirements of associated functions that must have been previously called. This array MUST be the same array passed as argument state in the previous call to nag_rand_init_repeatable (g05kfc) or nag_rand_init_nonrepeatable (g05kgc).
On entry: contains information on the selected base generator and its current state.
On exit: contains updated information on the state of the generator.
4:     x[n]Nag_BooleanOutput
On exit: the $n$ logical values.
5:     failNagError *Input/Output
The NAG error argument (see Section 3.6 in the Essential Introduction).

## 6  Error Indicators and Warnings

NE_ALLOC_FAIL
Dynamic memory allocation failed.
On entry, argument $⟨\mathit{\text{value}}⟩$ had an illegal value.
NE_INT
On entry, ${\mathbf{n}}=⟨\mathit{\text{value}}⟩$.
Constraint: ${\mathbf{n}}\ge 0$.
NE_INTERNAL_ERROR
An internal error has occurred in this function. Check the function call and any array sizes. If the call is correct then please contact NAG for assistance.
NE_INVALID_STATE
On entry, state vector has been corrupted or not initialized.
NE_REAL
On entry, ${\mathbf{p}}=⟨\mathit{\text{value}}⟩$.
Constraint: $0.0\le {\mathbf{p}}\le 1.0$.

Not applicable.

Not applicable.

None.

## 10  Example

This example prints the first $20$ pseudorandom logical values generated by nag_rand_logical (g05tbc) after initialization by nag_rand_init_repeatable (g05kfc), when the probability of a Nag_TRUE value is $0.5$.

### 10.1  Program Text

Program Text (g05tbce.c)

None.

### 10.3  Program Results

Program Results (g05tbce.r)