rndi#

Purpose#

Returns a matrix of random integers from a user defined range.

Format#

y = rndi(r, c[, range])#

{ y, newstate } = rndi(r, c, range, state)

Parameters:

r (scalar) – row dimension.
c (scalar) – column dimension.
range (matrix) – Optional argument. 2x1 matrix, the requested range of the random integers. The first element is the range minimum and the second element is the range maximum. If range is not supplied, the default range is \(0 ≤ y < 2^{32}\).
state (scalar or opaque vector) –
Optional argument.

scalar case

state = starting seed value only. If -1, GAUSS computes the starting seed based on the system clock.

opaque vector case

state = the state vector returned from a previous call to one of the rnd random number functions.

Returns:

y (RxC matrix) – of random integers in the specified range.
newstate (Opaque vector) – the updated state.

Examples#

Basic example#

// Create a 10x5 vector of random
// integers between 0 and 2^32 - 1
r_int = rndi(10, 5);

Basic range#

// Create a 10x1 vector of random
// integers between 1 and 100
range_start = 1;
range_end = 100;
idx = rndi(10, 1, range_start | range_end);

Sample with replacement from a dataset#

// Load data from the 'fueleconomy' dataset
// in the GAUSS examples directory
file_name = getGAUSSHome("examples/fueleconomy.dat");
fueleconomy = loadd(file_name);

// Create a 100x1 vector of random
// integers between 1 and 100
range_start = 1;
range_end = rows(fueleconomy);
idx = rndi(100, 1, range_start | range_end);

// Draw a 100 observation sample from 'fueleconomy'
fuel_sample = fueleconomy[idx, .];

Using a state-vector#

// Create a 1050x1 vector of random
// integers between 20 and 150
seed_start = 5423432;
range = { 20, 150 };
{ idx, state } = rndi(1050, 1, range, seed_start);

Remarks#

r and c will be truncated to integers if necessary.

This generator is automatically seeded using the system clock when GAUSS first starts. However, that can be overridden using the rndseed statement, or passing in a seed or state as the last input to rndi().