[ https://issues.apache.org/jira/browse/SYSTEMML-676?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Mike Dusenberry updated SYSTEMML-676: ------------------------------------- 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, {{X1[:,:]}}, should also be valid, regardless if it is useful. was: 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. > Improve PyDML Slicing > --------------------- > > Key: SYSTEMML-676 > URL: https://issues.apache.org/jira/browse/SYSTEMML-676 > Project: SystemML > Issue Type: Improvement > Reporter: Mike Dusenberry > > 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, {{X1[:,:]}}, should also be valid, regardless if it > is useful. -- This message was sent by Atlassian JIRA (v6.3.4#6332)