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Bug 1286 - Automatically adjust the prototype of functors for CwiseNullaryOp
Summary: Automatically adjust the prototype of functors for CwiseNullaryOp
Alias: None
Product: Eigen
Classification: Unclassified
Component: Core - general (show other bugs)
Version: 3.3 (current stable)
Hardware: All All
: Normal Feature Request
Assignee: Nobody
Depends on:
Blocks: 457 720
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Reported: 2016-08-31 12:46 UTC by Gael Guennebaud
Modified: 2019-12-04 16:11 UTC (History)
4 users (show)

patch (19.07 KB, patch)
2016-08-31 12:46 UTC, Gael Guennebaud
no flags Details | Diff

Description Gael Guennebaud 2016-08-31 12:46:29 UTC
Created attachment 726 [details]

Current functors passed to NullaryExpr must implement both operator()(i) and operator()(i,j) plus specialize internal::functor_has_linear_access<> for non trivial functors. This is rather painful and cumbersome to document (hence, this is currently not really documented!).

The proposed patch automatically detect whether the functor expose one or multiple of the following operators:


and then a little helper augments the input functors with the missing operators.

With this change, no need to provide operator()(i,j) if nor i nor j are required (e.g.,  for random, and constant).

I'd like to push this change in 3.3 as it considerably help in documenting and using NullaryExpr.
Comment 1 Christoph Hertzberg 2016-08-31 13:14:50 UTC
I'm all for this!
Comment 2 Gael Guennebaud 2018-10-02 07:26:12 UTC
This patch has been merged a while ago, it's even part of 3.3
Comment 3 Nobody 2019-12-04 16:11:05 UTC
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