59 lines
2.2 KiB
C
59 lines
2.2 KiB
C
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// This program generates a collection of random numbers which follow the
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// distribution whose name is given in input by the user when calling the
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// program and outputs an histogram of the result. Maximum and minimum of
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// the range must also be given. The random number distribution functions
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// are taken from the GSL library at:
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// https://www.gnu.org/software/gsl/doc/html/randist.html
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#include <stdio.h>
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#include <string.h>
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#include <gsl/gsl_randist.h>
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#include <gsl/gsl_rng.h>
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#include <gsl/gsl_histogram.h>
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int main (int argc, char** argv)
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{
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// An histogram with 100 bins which range from 0 to 100 is set:
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size_t bins = 100;
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int low = atoi(argv[2]);
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int upp = atoi(argv[3]);
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gsl_histogram * histo = gsl_histogram_alloc(bins);
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gsl_histogram_set_ranges_uniform(histo, low, upp);
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// The random number generator is set:
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gsl_rng* gen = gsl_rng_alloc(gsl_rng_taus);
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// 100'000 random numbers are generated and put into the histogram:
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size_t N = 100000;
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for (size_t i = 0; i < N; i++)
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{
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if (strcmp(argv[1], "binomial") == 0)
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gsl_histogram_increment(histo, gsl_ran_binomial(gen, 0.3, 10));
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if (strcmp(argv[1], "poisson") == 0)
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gsl_histogram_increment(histo, gsl_ran_poisson(gen, 1));
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if (strcmp(argv[1], "uniform") == 0)
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gsl_histogram_increment(histo, gsl_rng_get(gen)*100);
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if (strcmp(argv[1], "gaussian") == 0)
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gsl_histogram_increment(histo, gsl_ran_gaussian(gen, 5)+30);
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if (strcmp(argv[1], "wigner") == 0)
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gsl_histogram_increment(histo, gsl_ran_cauchy(gen, 10)+20);
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if (strcmp(argv[1], "landau") == 0)
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gsl_histogram_increment(histo, gsl_ran_landau(gen));
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if (strcmp(argv[1], "chi2") == 0)
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gsl_histogram_increment(histo, gsl_ran_gamma(gen, 5, 2));
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if (strcmp(argv[1], "exponential") == 0)
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gsl_histogram_increment(histo, gsl_ran_exponential(gen, 5));
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if (strcmp(argv[1], "student") == 0)
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gsl_histogram_increment(histo, gsl_ran_tdist(gen, 3));
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if (strcmp(argv[1], "fischer") == 0)
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gsl_histogram_increment(histo, gsl_ran_fdist(gen, 3, 4));
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}
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// The histogram is given in output:
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gsl_histogram_fprintf (stdout, histo, "%g", "%g");
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// The memory is freed.
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gsl_rng_free(gen);
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gsl_histogram_free(histo);
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return 0;
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}
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