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Génération de nombres aléatoires
Utilisez les fonctions rand, randn et randi pour créer des séries de nombres pseudo-aléatoires. Utilisez la fonction randperm pour créer un vecteur d’entiers permutés de façon aléatoire. Utilisez la fonction rng pour contrôler la répétabilité de vos résultats. Utilisez la classe RandStream si vous avez besoin d’un contrôle plus avancé de la génération de nombres aléatoires.
Fonctions
Rubriques
Générer des nombres aléatoires
- Create Arrays of Random Numbers
Userand,randi,randn, andrandpermto create arrays of random numbers. - Nombres entiers aléatoires
Cet exemple montre comment créer un tableau de valeurs entières aléatoires tirées d’une distribution uniforme discrète d’un ensemble spécifique de nombres. - Why Do Random Numbers Repeat After Startup?
Avoid repetition of random number arrays when MATLAB® restarts. - Replace Discouraged Syntaxes of rand and randn
Replace Discouraged Syntaxes ofrandandrandn.
Contrôler la génération de nombres aléatoires
- Controlling Random Number Generation
This example shows how to use therngfunction, which provides control over random number generation. - Generate Random Numbers That Are Repeatable
This example shows how to repeat arrays of random numbers by specifying the generator algorithm and seed first. Every time you initialize the generator using the same algorithm and seed, you always get the same result. - Generate Random Numbers That Are Different
This example shows how to avoid repeating the same random number arrays when MATLAB restarts.
Contrôler plusieurs séries ou sous-séries
- Managing the Global Stream Using RandStream
This example shows how to use theRandStreamclass to control random number generation from the global stream. - Multiple Streams
This example usesRandStreamto create multiple, independent random number streams. - Creating and Controlling a Random Number Stream
This example shows how to useRandStreamto create random number streams and substreams.
Informations connexes
Sélection d՚exemples
Nombres aléatoires dans une plage spécifique
Cet exemple montre comment créer un tableau de nombres aléatoires à virgule flottante tirés d’une distribution uniforme dans l’intervalle ouvert (50, 100).
Random Numbers from Normal Distribution with Specific Mean and Variance
Create an array of random floating-point numbers that are drawn from a normal distribution having a mean of 500 and variance of 25.
Random Numbers Within a Sphere
Create random points within the volume of a sphere, as described by Knuth [1]. The sphere in this example is centered at the origin and has a radius of 3.
Random Numbers and Vectors from Multivariate Normal Distributions
Generate and visualize random numbers and vectors that are drawn from multivariate normal distributions. This example discusses the steps to generate and visualize random numbers and vectors that are drawn from univariate, bivariate, and trivariate normal distributions. The randn function generates random numbers from the standard normal distribution. To generate random numbers and vectors from a multivariate normal distribution with a specific mean and covariance, you can transform the data generated from the standard normal distribution. Starting from a -dimensional random variable that follows a normal distribution with zero mean and a unit covariance matrix, you can transform to . The variable follows the normal distribution with mean and covariance matrix . The covariance matrix is a symmetric and positive definite (nonsingular) matrix, which indicates that the multivariate normal distribution is also nondegenerate. Therefore, you can perform Cholesky decomposition on to obtain the upper triangular matrix . A multivariate normal distribution that is degenerate, where is not full rank (or singular), is beyond the scope of this example.
