00001 /* 00002 COSTA: Problem solving environment for data assimilation 00003 Copyright (C) 2005 Nils van Velzen 00004 00005 This library is free software; you can redistribute it and/or 00006 modify it under the terms of the GNU Lesser General Public 00007 License as published by the Free Software Foundation; either 00008 version 2.1 of the License, or (at your option) any later version. 00009 00010 This library is distributed in the hope that it will be useful, 00011 but WITHOUT ANY WARRANTY; without even the implied warranty of 00012 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00013 Lesser General Public License for more details. 00014 00015 You should have received a copy of the GNU Lesser General Public 00016 License along with this library; if not, write to the Free Software 00017 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 00018 */ 00019 00020 /** 00021 \file cta_util_statistics.h 00022 \brief Utility for calculating a realization of a standard normal distribution. 00023 \note This is just a set of utility routines it does not define any COSTA component 00024 00025 */ 00026 00027 #ifndef CTA_UTIL_STATISTICS_H 00028 #define CTA_UTIL_STATISTICS_H 00029 #include "cta_system.h" 00030 00031 #ifdef __cplusplus 00032 extern "C" { 00033 #endif 00034 00035 /** \brief Initialize the random generator. 00036 * \note only initialize the random generator once. 00037 * \param seed I some positive initial seed 00038 */ 00039 CTAEXPORT void CTA_rand_seed(int seed); 00040 00041 00042 /** \brief Get an uniform random number from the interval [0 1]. 00043 * 00044 * \param x O receives the random number 00045 * \return error status: CTA_OK if successful 00046 */ 00047 CTAEXPORT int CTA_rand_u(double *x); 00048 00049 00050 /** \brief Get a random number from a normal distribution whit mean 0 and 00051 * standard deviation 1. 00052 * 00053 * \param x O receives the random number 00054 * \return error status: CTA_OK if successful 00055 */ 00056 CTAEXPORT int CTA_rand_n(double *x); 00057 00058 #ifdef __cplusplus 00059 } 00060 #endif 00061 #endif 00062