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https://issues.apache.org/jira/browse/SYSTEMML-676?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Mike Dusenberry updated SYSTEMML-676:
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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.
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, {{X1[:,:]}}, 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
> Components: Parser, PyDML
> 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, {{X\[:,:]}}, should also be valid, regardless if it
> is useful.
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