Ivan Vergiliev IvanVergiliev
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| import org.apache.spark.sql.Column | |
| def treeFold( | |
| columns: List[Column], | |
| initialValue: Column, | |
| op: (Column, Column) => Column | |
| ): Column = { | |
| if (columns.isEmpty) { | |
| initialValue | |
| } else if (columns.length == 1) { |
IvanVergiliev
/ exponential_tree_transform
Created
June 21, 2021 16:01
Exponential Tree Transformation Complexity
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| f(H) = | |
| f(H - 1) // for the first transform call | |
| + | |
| f(H - 1) // for the second transform call | |
| = 2 * f(H - 1) = | |
| = 2 * 2 * f(H - 2) = ... = 2 ^ (H - 1) * f(1) // unfolding further |
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| val andPredicates: Array[Column] = parseAndPredicates(...) | |
| val compositePredicate: Column = andPredicates.foldLeft(lit(true))((x, y) => x && y) |
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