Good morning Rusty,
Sent with ProtonMail Secure Email. ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ On Friday, November 30, 2018 7:46 AM, Rusty Russell <ru...@rustcorp.com.au> wrote: > ZmnSCPxj zmnsc...@protonmail.com writes: > > > Good morning all, > > > > > I initially suggested we could just have a 2-byte "number of total > > > pieces", but it turns out there's a use-case where that doesn't work > > > well: splitting the bill. There each payer is unrelated, so doesn't > > > know how the others are paying. > > > > This would also not work well in case of a dynamic algorithm that greedily > > tries to pay the whole amount at once, then splits it if it does not fit, > > with each split also being liable to splitting. > > Such a dynamic algorithm would not know in the first place how many splits > > it will take, but it will know the total amount it intends to deliver. > > Well, that would have worked because received takesmax of the values > received, ie, sender starts with A and B, both with "numpieces=2", > then splits B into BA and BB, both with "numpieces=3". Consider a network where there are 4 paths between payer and payee. 3 paths have low capacity but negligible feerate, while the 4th has high capacity but ridiculously high feerates measurable in whole microbitcoins. The rational thing to try, when paying a somewhat large amount but trying to minimize fees, would be to split among the three lowcost paths. But what if 2 of those paths fail? It would be better to merge them into a single payment along the expensive 4th path. However, the remaining succeeding path has already given `numpaths`=3. Using `numpaths` overcommits to what you will do in the future, and is unnecessary anyway. The payee is interested in the total value, not the details of the split. Regards, ZmnSCPxj > > But it's bad for the separate-payer case anyway, so... > > Thanks, > Rusty. _______________________________________________ Lightning-dev mailing list Lightning-dev@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/lightning-dev
