On 7/27/11 7:30 AM, Gilles Sadowski wrote: >> Hello. >> >>>>> In project SIRIUS (CNES), we have some need for a Matrix33 (3 >>>>> columns, >>>>> 3 >>>>> rows) object. It is very common to use this kind of matrix to apply >>>>> rotation to a position vector (vector3D). >>>>> >>>>> The incompatibility between the Vector3D of geometry package and >>>>> the matrix/vectors of the linear package is a lack that we propose
>>>>> to fill by creating a "Matrix33" in the geometry.threed package. >>>> Looks finie to me. >> Except for the name: "Matrix33" -> "Matrix3D". +1 : ok to call it Matrix3D. >> >>> [...] >>> >>>>> We will also propose some new constructors to build gaps between >>>>> this new matrix and the matrix of linear package. >>>> Yes, having a way to change from one view to the other is a clear need. >>> Yes, we prefer to add a constructor from Array2DRowRealMatrix and a >>> getter (that returns a Array2DRowRealMatrix) than to implement the >>> whole interface RealMatrix >> There are not that many methods. It's preferable to implement "RealMatrix" >> lest there will be two API eveolving independently. > >+1 The key point here is that the matrix from linear package are not compatible with Vector3D. -> This is the main point we wanted to solve by creating a new matrix class. So we have imagined three solutions : a) inherit the RealMatrix, but we need to add a multiply(Vector3D v) method and some other methods b) create an adapter class which contains an Array2DRealMatrix : this may be heavy because we need to implement other methods c) create a rather small class with only a few methods that answer our needs (multiplication with Vector3D, transposition, ...). This class should also implement a specific constructor and a specific getter to fill the gap with the RealMatrix. The other advantage of the c) solution is that it allows to implement faster operations. Yannick > >> I'm sure that somebody will help implement the missing bits if necessary. >> >>> (or inherit the AbstractMatrix). >> At the moment, I tend to agree on this point, given what I've just >> observed with this benchmark: > >+1 - the difference is expected, since AbstractRealMatrix has to use >getters/setters and Array2DRowRealMatrix can do direct array access. I guess to maximize reuse a) the array-based operations could be extracted into a static utils class somewhere and used by both impls or b) the new class could extend Array2DRowRealMatrix. > >Phil --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org For additional commands, e-mail: dev-h...@commons.apache.org
