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https://issues.apache.org/jira/browse/SYSTEMML-2078?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16394389#comment-16394389
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Matthias Boehm commented on SYSTEMML-2078:
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thanks for asking [~Guobao] - I would prefer not to introduce a stateful
builtin function like that because it would be very hard to properly integrate
it for the general case. For example, what are the semantics if this builtin
function is called out of {{parfor}} iterations?
Instead, this task captures two much simpler aspects:
1) The support for predefined constants such as NaN, and INF, which people
currently have to write as 0.0/0.0 and 1.0/0.0, respectively. Providing the
builtin constants just makes several scripts more readable and less error prone.
2) A changed scoping semantics, where the parent environment (including live
variables) is visible (but cannot be modified) in called functions even though
these variables are not explicitly passed. This would be consistent with R and
would also allow simple global constant (simply assign in the main script or
some function and these variables become globally available).
> Support for global constants
> ----------------------------
>
> Key: SYSTEMML-2078
> URL: https://issues.apache.org/jira/browse/SYSTEMML-2078
> Project: SystemML
> Issue Type: Sub-task
> Reporter: Matthias Boehm
> Priority: Major
>
> Similar to R, where variables of the surrounding context are accessible, this
> task aims to introduce global constant variables. Furthermore, we should also
> add builtin constants such as NaN, INF, and PI.
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