Ignore:
Timestamp:
Jul 23, 2012, 5:29:18 PM (11 years ago)
Author:
Oleksandr Motsak <motsak@…>
Branches:
(u'jengelh-datetime', 'ceac47cbc86fe4a15902392bdbb9bd2ae0ea02c6')(u'spielwiese', '2234726c50d679d6664181a5c72f75a6fd64a787')
Children:
6779bb431ba1eced98b7cb0e1fed5fbfef1f0244
Parents:
98223c2d11013c57837511c1adb1ef9a16193b3d
git-author:
Oleksandr Motsak <motsak@mathematik.uni-kl.de>2012-07-23 17:29:18+02:00
git-committer:
Oleksandr Motsak <motsak@mathematik.uni-kl.de>2012-07-25 15:25:07+02:00
Message:
moved the definition of p_GetShortExpVector(poly, ring) to p_polys.cc
File:
1 edited

Legend:

Unmodified
Added
Removed
  • libpolys/polys/monomials/p_polys.cc

    r98223c rf3094a  
    1010
    1111
    12 
    1312#include "config.h"
     13
     14#include <ctype.h>
     15
     16#include <omalloc/omalloc.h>
     17
    1418#include <misc/auxiliary.h>
    1519
    16 #include <ctype.h>
    17 #include <omalloc/omalloc.h>
    1820#include <misc/options.h>
    1921#include <misc/intvec.h>
     
    40914093  }
    40924094}
     4095
     4096/***************************************************************
     4097 *
     4098 * Storage Managament Routines
     4099 *
     4100 ***************************************************************/
     4101
     4102
     4103static inline unsigned long GetBitFields(long e,
     4104                                         unsigned int s, unsigned int n)
     4105{
     4106#define Sy_bit_L(x)     (((unsigned long)1L)<<(x))
     4107  unsigned int i = 0;
     4108  unsigned long  ev = 0L;
     4109  assume(n > 0 && s < BIT_SIZEOF_LONG);
     4110  do
     4111  {
     4112    assume(s+i < BIT_SIZEOF_LONG);
     4113    if (e > (long) i) ev |= Sy_bit_L(s+i);
     4114    else break;
     4115    i++;
     4116  }
     4117  while (i < n);
     4118  return ev;
     4119}
     4120
     4121// Short Exponent Vectors are used for fast divisibility tests
     4122// ShortExpVectors "squeeze" an exponent vector into one word as follows:
     4123// Let n = BIT_SIZEOF_LONG / pVariables.
     4124// If n == 0 (i.e. pVariables > BIT_SIZE_OF_LONG), let m == the number
     4125// of non-zero exponents. If (m>BIT_SIZEOF_LONG), then sev = ~0, else
     4126// first m bits of sev are set to 1.
     4127// Otherwise (i.e. pVariables <= BIT_SIZE_OF_LONG)
     4128// represented by a bit-field of length n (resp. n+1 for some
     4129// exponents). If the value of an exponent is greater or equal to n, then
     4130// all of its respective n bits are set to 1. If the value of an exponent
     4131// is smaller than n, say m, then only the first m bits of the respective
     4132// n bits are set to 1, the others are set to 0.
     4133// This way, we have:
     4134// exp1 / exp2 ==> (ev1 & ~ev2) == 0, i.e.,
     4135// if (ev1 & ~ev2) then exp1 does not divide exp2
     4136unsigned long p_GetShortExpVector(poly p, const ring r)
     4137{
     4138  assume(p != NULL);
     4139  if (p == NULL) return 0;
     4140  unsigned long ev = 0; // short exponent vector
     4141  unsigned int n = BIT_SIZEOF_LONG / r->N; // number of bits per exp
     4142  unsigned int m1; // highest bit which is filled with (n+1)
     4143  unsigned int i = 0, j=1;
     4144
     4145  if (n == 0)
     4146  {
     4147    if (r->N <2*BIT_SIZEOF_LONG)
     4148    {
     4149      n=1;
     4150      m1=0;
     4151    }
     4152    else
     4153    {
     4154      for (; j<=(unsigned long) r->N; j++)
     4155      {
     4156        if (p_GetExp(p,j,r) > 0) i++;
     4157        if (i == BIT_SIZEOF_LONG) break;
     4158      }
     4159      if (i>0)
     4160        ev = ~((unsigned long)0) >> ((unsigned long) (BIT_SIZEOF_LONG - i));
     4161      return ev;
     4162    }
     4163  }
     4164  else
     4165  {
     4166    m1 = (n+1)*(BIT_SIZEOF_LONG - n*r->N);
     4167  }
     4168
     4169  n++;
     4170  while (i<m1)
     4171  {
     4172    ev |= GetBitFields(p_GetExp(p, j,r), i, n);
     4173    i += n;
     4174    j++;
     4175  }
     4176
     4177  n--;
     4178  while (i<BIT_SIZEOF_LONG)
     4179  {
     4180    ev |= GetBitFields(p_GetExp(p, j,r), i, n);
     4181    i += n;
     4182    j++;
     4183  }
     4184  return ev;
     4185}
     4186
    40934187/***************************************************************
    40944188 *
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