[SYSTEMDS-676] Improve PyDML Slicing

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: SystemML 0.10
• Component/s: Parser, PythonAPI
• Epic Link: Improve PyDML Language
• Assignee: Mike Dusenberry
• Reporter: Mike Dusenberry
• Created: 09/May/16 23:08
• Updated: 02/Dec/23 19:05
• Resolved: 16/May/16 18:30

Description

Currently, slicing correctly uses inclusive lower and exclusive upper bounds. However, a really useful piece of slicing syntax we are currently missing from PyDML is the ability to have implicit lower or upper bounds, i.e., X[:3,] should return all rows up to (but not including) 3. This means that the implicit lower bound is 0. Similarly, X[2:,] should return all rows starting at row 2 (0-based), which implies that the upper bound is equal to the number of rows of X.

We should update the grammar to allow these cases, row both row and column slicing. More generally, X[:,:], should also be valid, regardless if it is useful.

Issue Links

• is related to: SYSTEMDS-689 Add Negative Bounds to PyDML
• is related to: SYSTEMDS-690 Add reverse slicing to PyDML
• is related to: SYSTEMDS-516 Index Range Slicing Should Allow Implicit Upper Or Lower Bounds