priority for transactions

[Rothgar]

In response to the discussion here:

https://gist.github.com/gavinandresen/2961409

I don't know why priority and fee/kB need to be considered separately.  Why can't there just be one metric

priority = [sum(value*age) + 1000000000* fee] * (1000 + size of previous txouts) / [(1000 + size of this txn's txouts)* size]

and only priority is used to decide weather to accept or reject a transaction.  That way if someone includes a fee of one satoshi there will be a benefit to the priority of the transaction (by about 100/size) and it's not just a gift to the miners.  I believe this will make a more fluid market for transaction fees.  If the recommended .0001 was added for a fee of a transaction of 1 kb then there would be a priority increase of around 100,000.   Of course, more generally

priority = [sum(value*age) + beta* fee] * (1000 + size of previous txouts) / [(1000 + size of this txn's txouts)* size]

and the value of beta is to be determined.  There is probably a sweet spot for beta.  For example the recommend .0001 fee adds the priority of a one year (or four year) old coin. 

Then we don't have to worry about fee/kb AND priority. 

[Rothgar]

If beta was 5256000 then each fee of .0001 would correspond to a year old bitcent (.01 BTC).  So that a new transaction sending .0101 to .01 with a .0001 fee would have the same priority of a transaction sending .01 to .01 with the input a year old.