Communications Toolbox

randsrc

Generate random matrix using prescribed alphabet

Syntax

• out = randsrc;
  out = randsrc(m);
  out = randsrc(m,n);
  out = randsrc(m,n,alphabet);
  out = randsrc(m,n,[alphabet; prob]);
  out = randsrc(m,n,...,state);
  

Description

out = randsrc generates a random scalar that is either -1 or 1, with equal probability.

out = randsrc(m) generates an m-by-m matrix, each of whose entries independently takes the value -1 with probability 1/2, and 1 with probability 1/2.

out = randsrc(m,n) generates an m-by-n matrix, each of whose entries independently takes the value -1 with probability 1/2, and 1 with probability 1/2.

out = randsrc(m,n,alphabet) generates an m-by-n matrix, each of whose entries is independently chosen from the entries in the row vector alphabet. Each entry in alphabet occurs in out with equal probability. Duplicate values in alphabet are ignored.

out = randsrc(m,n,[alphabet; prob]) generates an m-by-n matrix, each of whose entries is independently chosen from the entries in the row vector alphabet. Duplicate values in alphabet are ignored. The row vector prob lists corresponding probabilities, so that the symbol alphabet(k) occurs with probability prob(k), where k is any integer between one and the number of columns of alphabet. The elements of prob must add up to one.

out = randsrc(m,n,...,state); is the same as the two preceding syntaxes, except that it first resets the state of the uniform random number generator rand to the integer state.

Examples

To generate a 10-by-10 matrix whose elements are uniformly distributed among members of the set {-3,-1,1,3}, you can use either of these commands.

• out = randsrc(10,10,[-3 -1 1 3]);
  out = randsrc(10,10,[-3 -1 1 3; .25 .25 .25 .25]);
  

To skew the probability distribution so that -1 and 1 each occur with probability .3, while -3 and 3 each occur with probability .2, use this command.

• out = randsrc(10,10,[-3 -1 1 3; .2 .3 .3 .2]);
  

See Also
rand, randint, randerr

randint

rcosfir