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Control random number generator



rng(seed) specifies the seed for the MATLAB® random number generator. For example, rng(1) initializes the Mersenne Twister generator using a seed of 1.

The rng function controls the global stream, which determines how the rand, randi, randn, and randperm functions produce a sequence of random numbers. To create one or more independent streams separate from the global stream, see RandStream and RandStream.create.


rng(seed,generator) also specifies the type of random number generator to use. For example, rng(0,'philox') initializes the Philox 4x32 random generator with a seed of 0.


s = rng returns the current random number generator settings in a structure s.


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Set the random number generator to the default seed (0) and algorithm (Mersenne Twister), then save the generator settings.

s = rng
s = struct with fields:
     Type: 'twister'
     Seed: 0
    State: [625x1 uint32]

Create a 1-by-5 row vector of random values between 0 and 1.

x = rand(1,5)
x = 1×5

    0.8147    0.9058    0.1270    0.9134    0.6324

Change the generator seed and algorithm, and create a new random row vector.

xnew = rand(1,5)
xnew = 1×5

    0.5361    0.2319    0.7753    0.2390    0.0036

Now restore the original generator settings and create a random vector. The result matches the original row vector x created with the default generator.

xold = rand(1,5)
xold = 1×5

    0.8147    0.9058    0.1270    0.9134    0.6324

Input Arguments

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Generator initialization, specified as one of these options.

0Initialize the generator with a seed of 0.
positive integerInitialize the generator with the specified positive integer seed, such as 1.

Initialize the Mersenne Twister generator with a seed value of 0. Each MATLAB session starts with this default setting.

If you use parallel workers (requires Parallel Computing Toolbox™), 'default' initializes the Threefry 4x64 generator with 20 rounds and a seed value of 0. (since R2023a)

'shuffle'Initialize the generator based on the current time, resulting in a different sequence of random numbers after each call to rng.
structureInitialize the generator based on the settings contained in a structure with fields Type, Seed, and State.

Random number algorithm, specified as one of the options in the table. For more information on generator algorithms, see Creating and Controlling a Random Number Stream.

ValueGenerator NameGenerator Keyword
'twister'Mersenne Twistermt19937ar
'simdTwister'SIMD-oriented Fast Mersenne Twisterdsfmt19937
'combRecursive'Combined multiple recursivemrg32k3a
'multFibonacci'Multiplicative Lagged Fibonaccimlfg6331_64
'philox'Philox 4x32 generator with 10 roundsphilox4x32_10
'threefry'Threefry 4x64 generator with 20 roundsthreefry4x64_20

For legacy generators used in MATLAB versions 4.0 and 5.0, use one of these options.

ValueGenerator NameGenerator Keyword
'v4'Legacy MATLAB version 4.0 generatormcg16807
'v5uniform'Legacy MATLAB version 5.0 uniform generatorswb2712
'v5normal'Legacy MATLAB version 5.0 normal generatorshr3cong


  • When you perform parallel processing, do not use rng('shuffle') to set the random number stream on different workers to ensure independent streams since it seeds the random number generator based on the current time. This is especially true when the command is sent to multiple workers simultaneously, such as inside a parfor job. For independent streams on the workers, use the default behavior or consider using a unique substream on each worker using RandStream.

  • When you perform parallel processing, the default random number generators on the MATLAB client and MATLAB workers are different. If you need to generate the same random stream of numbers on the client and workers, you can use rng with the same generator type and seed (or consider using RandStream with the same generator type, seed, and normal transformation algorithm). For more information, see Control Random Number Streams on Workers (Parallel Computing Toolbox).

  • To use rng instead of the rand or randn functions with the 'seed', 'state', or 'twister' inputs, see Replace Discouraged Syntaxes of rand and randn.

Extended Capabilities

Version History

Introduced in R2011a

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