diff --git a/xdocs/userguide/random.xml b/xdocs/userguide/random.xml index e542284fd..183074bda 100644 --- a/xdocs/userguide/random.xml +++ b/xdocs/userguide/random.xml @@ -117,7 +117,7 @@ For the non-secure methods, starting with the same seed always produces the same sequence of values. Secure sequences started with the same seeds will diverge. When a new RandomDataImpl is created, the underlying - random number generators are not intialized. The first + random number generators are not initialized. The first call to a data generation method, or to a reSeed() method initializes the appropriate generator. If you do not explicitly seed the generator, it is by default seeded with the current time in milliseconds. @@ -176,15 +176,15 @@ for (int i = 0; i < 1000; i++) { however, generating them is much more difficult. The org.apache.commons.math.CorrelatedRandomVectorGenerator class - provides this service. In this case, the user must set a complete covariance matrix - instead of a simple standard deviations vector, this matrix gather both the variance + provides this service. In this case, the user must set up a complete covariance matrix + instead of a simple standard deviations vector. This matrix gathers both the variance and the correlation information of the probability law.

The main use for correlated random vector generation is for Monte-Carlo simulation of physical problems with several variables, for example to generate error vectors to be added to a nominal vector. A particularly - interesting case is when the generated vector should be drawn from a Multivariate Normal Distribution.

@@ -226,7 +226,7 @@ for (int i = 0; i < 1000; i++) { To select a random sample of objects in a collection, you can use the nextSample method in the RandomData interface. Specifically, if c is a collection containing at least - k objects, and ranomData is a + k objects, and randomData is a RandomData instance randomData.nextSample(c, k) will return an object[] array of length k consisting of elements randomly selected from the collection. If