Why you choose SPQR as the QR solver?

[ChenHancheng]

Hello:
In Mourikis's paper, he says givens rotation is a convenient and "can be computed efficiently" solution. When I debug a mono version of msckf, I find the H matrix is not very sparse. Is the H matrix in your code sparse or you find this method is faster than givens rotation?

[cggos]

i find givens rotation is faster than SPQR in measurementUpdate, you can find the code in this