[446935] | 1 | /**************************************** |
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| 2 | * Computer Algebra System SINGULAR * |
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| 3 | ****************************************/ |
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| 4 | /*************************************************************** |
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| 5 | * File: sbuckets.cc |
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| 6 | * Purpose: implementation of routines for sorting polys using |
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| 7 | * a bucket sort |
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| 8 | * Author: obachman (Olaf Bachmann) |
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| 9 | * Created: 9/00 |
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| 10 | * Version: $Id: sbuckets.cc,v 1.1 2000-12-31 15:17:47 obachman Exp $ |
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| 11 | *******************************************************************/ |
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| 12 | #include "sbuckets.h" |
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| 13 | #include "omalloc.h" |
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| 14 | #include "ring.h" |
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| 15 | #include "p_Procs.h" |
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| 16 | #include "p_polys.h" |
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| 17 | |
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| 18 | |
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| 19 | |
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| 20 | ////////////////////////////////////////////////////////////////////////// |
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| 21 | // Declarations |
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| 22 | // |
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| 23 | |
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| 24 | class sBucketPoly |
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| 25 | { |
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| 26 | public: |
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| 27 | poly p; |
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| 28 | long length; |
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| 29 | }; |
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| 30 | |
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| 31 | class sBucket |
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| 32 | { |
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| 33 | public: |
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| 34 | ring bucket_ring; |
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| 35 | long max_bucket; |
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| 36 | sBucketPoly buckets[BIT_SIZEOF_LONG - 3]; |
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| 37 | } |
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| 38 | ; |
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| 39 | |
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| 40 | static omBin sBucket_bin = omGetSpecBin(sizeof(sBucket)); |
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| 41 | |
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| 42 | ///////////////////////////////////////////////////////////////////////////// |
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| 43 | // internal routines |
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| 44 | // |
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| 45 | // returns floor(log_2(i)) |
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| 46 | inline int LOG2(int i) |
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| 47 | { |
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| 48 | assume (i > 0); |
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| 49 | int j = 0; |
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| 50 | |
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| 51 | do |
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| 52 | { |
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| 53 | i = i >> 1; |
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| 54 | if (i == 0) return j; |
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| 55 | j++; |
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| 56 | } |
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| 57 | while (1); |
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| 58 | |
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| 59 | return j; |
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| 60 | } |
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| 61 | |
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| 62 | ////////////////////////////////////////////////////////////////////////// |
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| 63 | // Creation/Destruction of buckets |
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| 64 | // |
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| 65 | sBucket_pt sBucketCreate(ring r) |
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| 66 | { |
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| 67 | sBucket_pt bucket = (sBucket_pt) omAlloc0Bin(sBucket_bin); |
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| 68 | bucket->bucket_ring = r; |
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| 69 | return bucket; |
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| 70 | } |
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| 71 | |
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| 72 | void sBucketDestroy(sBucket_pt *bucket) |
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| 73 | { |
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| 74 | assume(bucket != NULL); |
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| 75 | omFreeBin(*bucket, sBucket_bin); |
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| 76 | *bucket = NULL; |
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| 77 | } |
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| 78 | |
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| 79 | ///////////////////////////////////////////////////////////////////////////// |
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| 80 | // Convertion from/to SBpolys |
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| 81 | // |
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| 82 | |
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| 83 | static void sBucket_Merge_m(sBucket_pt bucket, poly p) |
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| 84 | { |
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| 85 | assume(p != NULL && pNext(p) == NULL); |
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| 86 | int length = 1; |
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| 87 | int i = 0; |
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| 88 | |
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| 89 | while (bucket->buckets[i].p != NULL) |
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| 90 | { |
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| 91 | p = p_Merge_q(p, bucket->buckets[i].p, bucket->bucket_ring); |
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| 92 | length += bucket->buckets[i].length; |
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| 93 | bucket->buckets[i].p = NULL; |
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| 94 | bucket->buckets[i].length = 0; |
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| 95 | i++; |
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| 96 | assume(LOG2(length) == i); |
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| 97 | } |
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| 98 | |
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| 99 | bucket->buckets[i].p = p; |
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| 100 | bucket->buckets[i].length = length; |
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| 101 | if (i > bucket->max_bucket) bucket->max_bucket = i; |
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| 102 | } |
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| 103 | |
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| 104 | void sBucket_Merge_p(sBucket_pt bucket, poly p, int length) |
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| 105 | { |
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| 106 | assume(bucket != NULL); |
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| 107 | assume(length <= 0 || length == pLength(p)); |
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| 108 | |
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| 109 | if (p == NULL) return; |
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| 110 | if (length <= 0) length = pLength(p); |
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| 111 | |
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| 112 | int i = LOG2(length); |
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| 113 | |
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| 114 | while (bucket->buckets[i].p != NULL) |
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| 115 | { |
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| 116 | p = p_Merge_q(p, bucket->buckets[i].p, bucket->bucket_ring); |
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| 117 | length += bucket->buckets[i].length; |
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| 118 | bucket->buckets[i].p = NULL; |
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| 119 | bucket->buckets[i].length = 0; |
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| 120 | i++; |
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| 121 | assume(LOG2(length) == i); |
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| 122 | } |
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| 123 | |
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| 124 | bucket->buckets[i].p = p; |
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| 125 | bucket->buckets[i].length = length; |
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| 126 | if (i > bucket->max_bucket) bucket->max_bucket = i; |
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| 127 | } |
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| 128 | |
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| 129 | void sBucket_Add_p(sBucket_pt bucket, poly p, int length) |
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| 130 | { |
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| 131 | assume(bucket != NULL); |
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| 132 | assume(length <= 0 || length == pLength(p)); |
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| 133 | |
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| 134 | if (p == NULL) return; |
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| 135 | if (length <= 0) length = pLength(p); |
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| 136 | |
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| 137 | int i = LOG2(length); |
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| 138 | |
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| 139 | while (bucket->buckets[i].p != NULL) |
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| 140 | { |
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| 141 | p = p_Add_q(p, bucket->buckets[i].p, length, bucket->buckets[i].length, |
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| 142 | bucket->bucket_ring); |
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| 143 | bucket->buckets[i].p = NULL; |
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| 144 | bucket->buckets[i].length = 0; |
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| 145 | i = LOG2(length); |
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| 146 | } |
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| 147 | |
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| 148 | bucket->buckets[i].p = p; |
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| 149 | bucket->buckets[i].length = length; |
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| 150 | if (i > bucket->max_bucket) bucket->max_bucket = i; |
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| 151 | } |
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| 152 | |
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| 153 | // Converts SBpoly into a poly and clears bucket |
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| 154 | // i.e., afterwards SBpoly == 0 |
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| 155 | void sBucketClearMerge(sBucket_pt bucket, poly *p, int *length) |
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| 156 | { |
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| 157 | poly pr = NULL; |
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| 158 | int lr = 0; |
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| 159 | int i = 0; |
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| 160 | |
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| 161 | while (bucket->buckets[i].p == NULL) |
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| 162 | { |
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| 163 | i++; |
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| 164 | if (i > bucket->max_bucket) goto done; |
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| 165 | } |
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| 166 | |
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| 167 | pr = bucket->buckets[i].p; |
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| 168 | lr = bucket->buckets[i].length; |
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| 169 | bucket->buckets[i].p = NULL; |
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| 170 | bucket->buckets[i].length = 0; |
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| 171 | i++; |
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| 172 | |
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| 173 | while (i <= bucket->max_bucket) |
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| 174 | { |
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| 175 | if (bucket->buckets[i].p != NULL) |
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| 176 | { |
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| 177 | pr = p_Merge_q(pr, bucket->buckets[i].p,bucket->bucket_ring); |
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| 178 | lr += bucket->buckets[i].length; |
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| 179 | bucket->buckets[i].p = NULL; |
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| 180 | bucket->buckets[i].length = 0; |
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| 181 | } |
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| 182 | i++; |
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| 183 | } |
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| 184 | |
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| 185 | done: |
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| 186 | *p = pr; |
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| 187 | *length = lr; |
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| 188 | bucket->max_bucket = 0; |
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| 189 | } |
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| 190 | |
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| 191 | // Converts SBpoly into a poly and clears bucket |
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| 192 | // i.e., afterwards SBpoly == 0 |
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| 193 | void sBucketClearAdd(sBucket_pt bucket, poly *p, int *length) |
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| 194 | { |
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| 195 | poly pr = NULL; |
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| 196 | int lr = 0; |
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| 197 | int i = 0; |
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| 198 | |
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| 199 | while (bucket->buckets[i].p == NULL) |
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| 200 | { |
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| 201 | i++; |
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| 202 | if (i > bucket->max_bucket) goto done; |
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| 203 | } |
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| 204 | |
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| 205 | pr = bucket->buckets[i].p; |
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| 206 | lr = bucket->buckets[i].length; |
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| 207 | bucket->buckets[i].p = NULL; |
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| 208 | bucket->buckets[i].length = 0; |
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| 209 | i++; |
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| 210 | |
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| 211 | while (i <= bucket->max_bucket) |
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| 212 | { |
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| 213 | if (bucket->buckets[i].p != NULL) |
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| 214 | { |
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| 215 | pr = p_Add_q(pr, bucket->buckets[i].p, lr, bucket->buckets[i].length, |
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| 216 | bucket->bucket_ring); |
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| 217 | bucket->buckets[i].p = NULL; |
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| 218 | bucket->buckets[i].length = 0; |
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| 219 | } |
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| 220 | i++; |
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| 221 | } |
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| 222 | |
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| 223 | done: |
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| 224 | *p = pr; |
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| 225 | *length = lr; |
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| 226 | bucket->max_bucket = 0; |
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| 227 | } |
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| 228 | |
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| 229 | ///////////////////////////////////////////////////////////////////////////// |
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| 230 | // Sorts a poly using BucketSort |
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| 231 | // |
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| 232 | |
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| 233 | poly sBucketSortMerge(poly p, ring r) |
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| 234 | { |
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| 235 | #ifdef HAVE_ASSUME |
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| 236 | int l_in = pLength(p); |
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| 237 | #endif |
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| 238 | |
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| 239 | if (p == NULL || pNext(p) == NULL) return p; |
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| 240 | |
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| 241 | sBucket_pt bucket = sBucketCreate(r); |
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| 242 | poly pn = pNext(p); |
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| 243 | |
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| 244 | do |
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| 245 | { |
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| 246 | pNext(p) = NULL; |
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| 247 | sBucket_Merge_m(bucket, p); |
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| 248 | p = pn; |
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| 249 | if (p == NULL) break; |
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| 250 | pn = pNext(pn); |
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| 251 | } |
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| 252 | while (1); |
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| 253 | |
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| 254 | int l_dummy; |
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| 255 | sBucketClearMerge(bucket, &pn, &l_dummy); |
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| 256 | sBucketDestroy(&bucket); |
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| 257 | |
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| 258 | p_Test(pn, r); |
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| 259 | #ifdef HAVE_ASSUME |
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| 260 | assume(l_dummy == pLength(pn)); |
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| 261 | assume(l_in == l_dummy); |
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| 262 | #endif |
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| 263 | return pn; |
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| 264 | } |
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| 265 | |
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| 266 | ///////////////////////////////////////////////////////////////////////////// |
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| 267 | // Sorts a poly using BucketSort |
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| 268 | // |
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| 269 | |
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| 270 | poly sBucketSortAdd(poly p, ring r) |
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| 271 | { |
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| 272 | #ifdef HAVE_ASSUME |
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| 273 | int l_in = pLength(p); |
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| 274 | #endif |
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| 275 | |
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| 276 | if (p == NULL || pNext(p) == NULL) return p; |
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| 277 | |
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| 278 | sBucket_pt bucket = sBucketCreate(r); |
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| 279 | poly pn = pNext(p); |
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| 280 | |
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| 281 | do |
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| 282 | { |
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| 283 | pNext(p) = NULL; |
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| 284 | sBucket_Add_p(bucket, p, 1); |
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| 285 | p = pn; |
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| 286 | if (p == NULL) break; |
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| 287 | pn = pNext(pn); |
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| 288 | } |
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| 289 | while (1); |
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| 290 | |
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| 291 | int l_dummy; |
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| 292 | sBucketClearAdd(bucket, &pn, &l_dummy); |
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| 293 | sBucketDestroy(&bucket); |
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| 294 | |
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| 295 | p_Test(pn, r); |
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| 296 | #ifdef HAVE_ASSUME |
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| 297 | assume(l_dummy == pLength(pn)); |
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| 298 | assume(l_in >= l_dummy); |
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| 299 | #endif |
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| 300 | return pn; |
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| 301 | } |
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| 302 | |
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| 303 | |
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| 304 | |
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| 305 | |
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| 306 | |
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| 307 | |
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