摘要：From:johndcook.com/blogFor a set of positive probabilitiespisumming to 1, their entropy is defined as(For this post, log will mean log base 2, notnatural log.)This post looks at a couple questions about computing entropy. First, are there any numerical problems computing entropy directly from the eq 阅读全文

摘要：Definitions:•Set of items: I={I1,I2,…,Im}•Transactions: D={t1,t2, …, tn}, tj∈I•Itemset: {Ii1,Ii2, …, Iik} ∈I•Support of an itemset: Percentage of transactions which contain that itemset.•Large (Frequent) itemset: Itemset whose number of occurrences is above a threshold.•Association Rule (AR): implic 阅读全文

摘要：A set has closure under an operation if performance of that operation on members of the set always produces a member of the same set. For example, the real numbers are closed under subtraction, but the natural numbers are not: 3 and 8 are both natural numbers, but the result of 3 − 8 is not a natura 阅读全文