Re: [eigen] Feature request - Prevent dynamic resizing of a matrix

[ Thread Index | Date Index | More Archives ]

It's added in trunk now (won't make it into 2.0).

Commit msg:
if defined, already initialized matrices won't be automatically
resized in assignments
uninitialized matrices may still be initialized


2009/1/28 Benoit Jacob <jacob.benoit.1@xxxxxxxxx>:
> OK, this has been a tough decision. Let's recall the arguments on both sides.
> In favor of automatic resizing:
> 1) This is more practical for the majority
> 2) This is the usual behavior of objects in C++ and in the C++ STL
> 3) Because this is what STL containers assume, it's almost required in
> order to allow convenient usage of STL containers with Eigen types
> Against automatic resizing:
> 1) Exactly what you say. Indeed automatic resizing can hide nasty bugs.
> So the default behavior will stay as it is right now, but what you
> propose, with a #define, sounds like a good solution to me. I
> implement it now. I'd rather call it EIGEN_NO_AUTOMATIC_RESIZING
> because i think we still want to allow explicitly calling resize().
> Notice that one could also consider implementing this behavior as a
> matrix type option. So you would do
> typedef Eigen::Matrix<float, Eigen::Dynamic, Eigen::Dynamic,
> Eigen::NonResizable> MyMat;
> and then objects of type MyMat have this behavior. Stuff to consider for 2.1...
> Cheers,
> Benoit
> 2009/1/28 Timothy Hunter <tjhunter@xxxxxxxxxxxx>:
>> Hello all,
>> I has been decided that the operator=(A,B) would resize A if it does
>> not fit the size of B, right?
>> I had a bug in my code I had problems to detect because of this
>> feature. It would be nice to have an assert that fails if the matrices
>> are of different size, and let the user decide to use this assert with
>> some flag definitions like EIGEN_DO_NOT_RESIZE_DYNAMIC_MATRICES.
>> Is it possible to do it with the current code?
>> -- Timothy Hunter

Mail converted by MHonArc 2.6.19+