Re: [eigen] Index type for PermutationMatrix and Transpositions

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On 25.01.2011 10:29, Helmut Jarausch wrote:
> On 01/25/11 10:11:22, Gael Guennebaud wrote:
>> Since it is unbelievable
>> that one day someone will perform a LU or LDLT dec on a matrix
>> requiring 64bits integers for the indices (think about the size of 
>> the
>> matrix!), I think it is safe to use int there too.

Just like 640k ought to be enough for everyone ;)

> I agree for dense matrices, but a tridiagonal matrix of size 2^32 
> isn't out of range (IMHO). So the situation might be different for 
> sparse matrices - even in the near future.

I agree on that. Why not make it default to MatrixType::Index and tell
users to use an appropriate IndexType in the first place? This could be
even smaller if the matrix never reaches sizes above 2^16 (2^15?).


Dipl.-Inf. Christoph Hertzberg
Cartesium 0.051
Universität Bremen
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