Re: [eigen] documentation |

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On 26.10.2014 23:46, Mathieu Dutour wrote:

I have many questions, first of all on the documentation.
1> Is there somewhere a full documentation in .pdf of
the software? That would help quite a lot.

`We don't generate that automatically, but with some effort you can
``generate that using the (existing) doxygen documentation (see below).
`

2> Related to that, when I do "cmake doc" in the top
directory, I get following error

`For cmake you need to create a separate (build) directory, go into that
``directory, then type
`
$ cmake {PATH_TO_EIGEN}
afterward, from that build directory you call
$ make doc

`This should automatically generate html documentation (the same as
``available via our homepage). For latex/pdf documentation look into
``eigen/doc/Doxyfile.in for GENERATE_LATEX and set it to YES (and run
```make doc` again). This should also solve your 3rd issue.
`

4> Is it possible to have a matrix whose size naturally grows?
I mean that in the enumration rays are continuously created and
need to be appended to the list (i.e. the matrix). Is it possible
to do that in eigen?

`Similar things have been requested from time to time, this was never
``considered a primary use-case of Eigen (it might come in future versions
``-- but most likely not yet in 3.3).
`

`You can use the conservativeResize function which keeps the existing
``elements of your matrix valid, but that is not very efficient (every
``resizing requires re-allocating and copying of the entire matrix).
``A (slightly) better idea is to start with a matrix big enough to hold
``the expected number of elements, then fill it column-by-column (or
``row-by-row) and address the currently valid elements with
` storage_matrix.leftCols(numberOfValidElements)

`Alternatively, store your data in a std::vector and access it using
``Eigen::Map.
`

5> Is there a way to have some number theoretic functions in
eigen? For example finding the integrl nullspace of a matrix?

`AFAIK, we don't provide anything at the moment (in fact, all
``decomposition lead to erroneous results in most cases for integral types).
``But you can use Eigen for basic integer matrix operations
``(multiplication and addition, accessing sub-blocks, etc) if that helps
``you implementing anything in that direction.
``If someone has a mature enough implementation of higher level integral
``operations, we can debate about adding it as an unsupported module.
`
Christoph
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