bundles/org.simantics.history/src/org/simantics/history/util/WeightedMedian2.java

   1 /*******************************************************************************\r
   2  * Copyright (c) 2007, 2011 Association for Decentralized Information Management in\r
   3  * Industry THTH ry.\r
   4  * All rights reserved. This program and the accompanying materials\r
   5  * are made available under the terms of the Eclipse Public License v1.0\r
   6  * which accompanies this distribution, and is available at\r
   7  * http://www.eclipse.org/legal/epl-v10.html\r
   8  *\r
   9  * Contributors:\r
  10  *     VTT Technical Research Centre of Finland - initial API and implementation\r
  11  *******************************************************************************/\r
  12 package org.simantics.history.util;\r
  13 \r
  14 import org.simantics.databoard.annotations.Optional;\r
  15 import org.simantics.databoard.annotations.Referable;\r
  16 \r
  17 /**\r
  18  * \r
  19  * @author toni.kalajainen\r
  20  */\r
  21 public class WeightedMedian2 {\r
  22 \r
  23         public int maxItems;\r
  24         public int itemCount;\r
  25         @Optional public Item median;\r
  26         \r
  27         // Relative pos = pos - median.accumulated weight \r
  28         public double rpos;\r
  29         \r
  30         public WeightedMedian2()\r
  31         {\r
  32                 maxItems = Integer.MAX_VALUE;\r
  33         }\r
  34         \r
  35         public WeightedMedian2(int maxItems)\r
  36         {\r
  37                 this.maxItems = maxItems;\r
  38         }\r
  39         \r
  40         public void clear() {\r
  41                 itemCount = 0;\r
  42                 median = null;\r
  43                 rpos = 0;\r
  44         }\r
  45         \r
  46         public void add(double weight, double value)\r
  47         {\r
  48                 if (weight<=0) return;\r
  49                 if (median == null) {\r
  50                         median = new Item( weight, value );\r
  51                         itemCount++;\r
  52                         rpos = weight / 2;\r
  53                         return;                 \r
  54                 }\r
  55                 \r
  56                 Item i = median;\r
  57                 while (true) {\r
  58                         \r
  59                         if (value>=i.low && value<=i.high) {\r
  60                                 double totWeight = i.weight+weight;\r
  61                                 i.value = ( i.value * i.weight + value * weight ) / totWeight;\r
  62                                 i.weight = totWeight;\r
  63                                 break;\r
  64                         }\r
  65                         \r
  66                         if (value < i.low) {\r
  67                                 \r
  68                                 // i = 1st, add new item as first\r
  69                                 if (i.prev==null) {\r
  70                                         i.prev = new Item( weight, value, null, i );\r
  71                                         itemCount++;\r
  72                                         break;\r
  73                                 }\r
  74                                 \r
  75                                 // value is between two items, add new item\r
  76                                 if (i.prev.high < value) {\r
  77                                         Item n = new Item( weight, value, i.prev, i );\r
  78                                         itemCount++;\r
  79                                         i.prev.next = n;\r
  80                                         i.prev = n;\r
  81                                         break;\r
  82                                 }\r
  83                                 \r
  84                                 i = i.prev;\r
  85                                 continue;\r
  86                         }                       \r
  87                         \r
  88                         if (value > i.high) {\r
  89                                 \r
  90                                 // i = last, add new item as last\r
  91                                 if (i.next==null) {\r
  92                                         i.next = new Item( weight, value, i, null );                                    \r
  93                                         itemCount++;\r
  94                                         break;\r
  95                                 }\r
  96                                 \r
  97                                 // value is between two items, add new item\r
  98                                 if (i.next.low > value) {\r
  99                                         Item n = new Item( weight, value, i, i.next );\r
 100                                         itemCount++;\r
 101                                         i.next.prev = n;\r
 102                                         i.next = n;\r
 103                                         break;\r
 104                                 }\r
 105                                 \r
 106                                 i = i.next;\r
 107                                 continue;\r
 108                         }\r
 109                 }\r
 110 \r
 111                 rpos += (value<median.low?-1:1) * weight / 2;\r
 112                 while (rpos<0) {\r
 113                         median = median.prev;\r
 114                         rpos += median.weight;\r
 115                 }\r
 116                 while (rpos>=median.weight) {\r
 117                         rpos -= median.weight;\r
 118                         median = median.next;\r
 119                 }\r
 120                 \r
 121                 if (itemCount>maxItems) coalesce();\r
 122         }\r
 123         \r
 124         public void coalesce() \r
 125         {\r
 126                 Item i = median.next;\r
 127                 while (i!=null) {\r
 128                         Item n = i.next;\r
 129                         if (n==null) break;\r
 130                         i.next = n.next;\r
 131                         if (n.next!=null) n.next.prev = i;\r
 132                         double totWeight = i.weight+n.weight;\r
 133                         i.high = n.high;\r
 134                         i.value = ( i.value * i.weight + n.value * n.weight ) / totWeight;\r
 135                         i.weight = totWeight;\r
 136                         i = i.next;\r
 137                 }\r
 138                 \r
 139                 i = median.prev;\r
 140                 while (i!=null) {\r
 141                         Item p = i.prev;\r
 142                         if (p==null) break;\r
 143                         i.prev = p.prev;\r
 144                         if (p.prev!=null) p.prev.next = i;\r
 145                         double totWeight = i.weight+p.weight;\r
 146                         i.low = p.low;\r
 147                         i.value = ( i.value * i.weight + p.value * p.weight ) / totWeight;\r
 148                         i.weight = totWeight;\r
 149                         i = i.prev;\r
 150                 }               \r
 151         }\r
 152         \r
 153         public double getMedian() \r
 154         {\r
 155                 if (median==null) return Double.NaN;\r
 156                 if (median.low == median.high) return median.value;\r
 157                 double d = median.high - median.low;\r
 158                 double r = rpos/median.weight;\r
 159                 return median.low + d*r;\r
 160         }\r
 161         \r
 162         @Override\r
 163         public String toString() {\r
 164                 StringBuilder sb = new StringBuilder();\r
 165                 sb.append( "Median="+getMedian()+" ");\r
 166                 \r
 167                 Item i = first();\r
 168                 while (i!=null) {\r
 169                         sb.append("(");\r
 170                         sb.append("value=");\r
 171                         if (i.low==i.high) sb.append(i.value); else \r
 172                                 sb.append(i.value+" ("+i.low+".."+i.high+")");\r
 173                         sb.append(", w="+i.weight);\r
 174                         if (i==median) {\r
 175                                 sb.append(", pos="+rpos);\r
 176                         }\r
 177                         sb.append(")");\r
 178                         i = i.next;\r
 179                 }\r
 180                 \r
 181                 return sb.toString();\r
 182         } \r
 183         \r
 184         Item first() {\r
 185                 if (median==null) return null;\r
 186                 Item i = median;\r
 187                 while (i.prev!=null) i = i.prev;\r
 188                 return i;\r
 189         }\r
 190         \r
 191         @Referable\r
 192         static public class Item {\r
 193                 public double weight;\r
 194                 public double low;\r
 195                 public double high;\r
 196                 public double value;\r
 197                 \r
 198                 public Item() {}\r
 199                 \r
 200                 public Item(double weight, double value) {\r
 201                         this.weight = weight;\r
 202                         this.low = this.high = value;\r
 203                 }\r
 204 \r
 205                 public Item(double weight, double value, Item prev, Item next) {\r
 206                         this.weight = weight;\r
 207                         this.value = this.low = this.high = value;\r
 208                         this.prev = prev;\r
 209                         this.next = next;\r
 210                 }\r
 211                 \r
 212                 @Optional\r
 213                 public Item prev;\r
 214                 \r
 215                 @Optional\r
 216                 public Item next;\r
 217                 \r
 218                 @Override\r
 219                 public String toString() {\r
 220                         if (low==high) return "(value="+value+", w="+weight+")";\r
 221                         return "(value="+value+" ("+low+".."+high+"), w="+weight+")";\r
 222                 }\r
 223         }\r
 224         \r
 225 }\r