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<h3 class="section">17.3 Random number generator initialization</h3>
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— Function: gsl_rng * <b>gsl_rng_alloc</b> (<var>const gsl_rng_type * T</var>)<var><a name="index-gsl_005frng_005falloc-1373"></a></var><br>
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<blockquote><p>This function returns a pointer to a newly-created
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instance of a random number generator of type <var>T</var>.
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For example, the following code creates an instance of the Tausworthe
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<pre class="example"> gsl_rng * r = gsl_rng_alloc (gsl_rng_taus);
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<p>If there is insufficient memory to create the generator then the
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function returns a null pointer and the error handler is invoked with an
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error code of <code>GSL_ENOMEM</code>.
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<p>The generator is automatically initialized with the default seed,
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<code>gsl_rng_default_seed</code>. This is zero by default but can be changed
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either directly or by using the environment variable <code>GSL_RNG_SEED</code>
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(see <a href="Random-number-environment-variables.html#Random-number-environment-variables">Random number environment variables</a>).
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<p>The details of the available generator types are
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described later in this chapter.
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</p></blockquote></div>
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— Function: void <b>gsl_rng_set</b> (<var>const gsl_rng * r, unsigned long int s</var>)<var><a name="index-gsl_005frng_005fset-1374"></a></var><br>
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<blockquote><p>This function initializes (or `seeds') the random number generator. If
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the generator is seeded with the same value of <var>s</var> on two different
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runs, the same stream of random numbers will be generated by successive
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calls to the routines below. If different values of <var>s</var> are
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supplied, then the generated streams of random numbers should be
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completely different. If the seed <var>s</var> is zero then the standard seed
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from the original implementation is used instead. For example, the
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original Fortran source code for the <code>ranlux</code> generator used a seed
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of 314159265, and so choosing <var>s</var> equal to zero reproduces this when
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using <code>gsl_rng_ranlux</code>.
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</p></blockquote></div>
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— Function: void <b>gsl_rng_free</b> (<var>gsl_rng * r</var>)<var><a name="index-gsl_005frng_005ffree-1375"></a></var><br>
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<blockquote><p>This function frees all the memory associated with the generator
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</p></blockquote></div>
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