00001 // @(#)root/base:$Id: TMathBase.cxx 20877 2007-11-19 11:17:07Z rdm $ 00002 // Authors: Rene Brun 08/02/2007 00003 00004 /************************************************************************* 00005 * Copyright (C) 1995-2007, Rene Brun and Fons Rademakers. * 00006 * All rights reserved. * 00007 * * 00008 * For the licensing terms see $ROOTSYS/LICENSE. * 00009 * For the list of contributors see $ROOTSYS/README/CREDITS. * 00010 *************************************************************************/ 00011 00012 ////////////////////////////////////////////////////////////////////////// 00013 // // 00014 // TMath Base functions // 00015 // // 00016 // Define the functions Min, Max, Abs, Sign, Range for all types. // 00017 // NB: These functions are unfortunately not available in a portable // 00018 // way in std::. // 00019 // // 00020 // More functions are defined in TMath.h. TMathBase.h is designed to be // 00021 // a stable file and used in place of TMath.h in the ROOT miniCore. // 00022 // // 00023 ////////////////////////////////////////////////////////////////////////// 00024 00025 #include "TMathBase.h" 00026 #include <math.h> 00027 00028 //______________________________________________________________________________ 00029 Long_t TMath::NextPrime(Long_t x) 00030 { 00031 // Return next prime number after x, unless x is a prime in which case 00032 // x is returned. 00033 00034 if (x <= 2) 00035 return 2; 00036 if (x == 3) 00037 return 3; 00038 00039 if (x % 2 == 0) 00040 x++; 00041 00042 Long_t sqr = (Long_t) sqrt((Double_t)x) + 1; 00043 00044 for (;;) { 00045 Long_t n; 00046 for (n = 3; (n <= sqr) && ((x % n) != 0); n += 2) 00047 ; 00048 if (n > sqr) 00049 return x; 00050 x += 2; 00051 } 00052 }
1.5.1