Hi,

Is there a way to resize a sparse matrix while preserving its values?

I think that similar to .setFromTriplets(), there should be a method .saveToTriplets() that would assist in copying from one matrix to another.

Indeed, there should be a conservativeResize. Fell free to add a bug report (http://eigen.tuxfamily.org/bz) so that we don't forget, or even better you could try to come up with a patch

Actually, there is already a patch there: http://eigen.tuxfamily.org/bz/show_bug.cgi?id=449 .

Gaël, to me it looks pretty good, but I did not look at it in detail because I don't know much about sparse matrices in Eigen.

Zoharl, perhaps you can try the patch, see whether it does what you wants, and let us know.

I'm not familiar with the library architecture to confirm if the patch cover all the cases.
I do think though that creating a new matrix through triplets for example should be safe enough.

patch applied.