A conditional frequent pattern tree is built for a specified item from its conditional pattern base: item prefixes are aggregated, and those below the support threshold are removed. section 4.6
Construct the tree by following these steps:
- Collect the prefix paths leading to the selected item and retain their support counts. section 4.6
- Add counts across paths, discard items below the chosen frequency threshold, and form the conditional tree. section 4.6
- Append the selected item to the retained prefixes to generate frequent patterns. section 4.6
Cheese
Cheese has the conditional pattern base {{Milk:1}, {Milk-Apples:1}}. With a frequency threshold of 2, Apples is removed, leaving {Milk:2}; adding Cheese produces {Milk-Cheese:2}. section 4.6
Table 4.11 Step 11 of the process where we have finished the details for the item Cheese
|
Items
|
Conditional pattern base
|
Conditional F-P tree
|
Frequent pattern generated
|
|---|---|---|---|
|
Cheese
|
{{Milk:1}, {Milk-Apples:1}}
|
{Milk:2}
|
{Milk-Cheese:2}
|
|
Bread
|
|||
|
Eggs
|
|||
|
Apples
|
Inspect the completed Cheese row showing its conditional pattern base, conditional tree, and generated frequent pattern. section 4.6
