How much ecm should i do???
 

how much ecm should i do before switching to msieve
i keep on finding that i have spent more time on ecm than msieve takes
this is with numbers between 85 and 100 digits that i am having this problem
i have did 35 digit ecm on a 97 digit number a couple of days ago and that turned out to be way too much
could people post what rules they would use for switching to msieve
i have searched the forum but found nothing
thanks

[QUOTE=themaster;125965]how much ecm should i do before switching to msieve
i keep on finding that i have spent more time on ecm than msieve takes
this is with numbers between 85 and 100 digits that i am having this problem
i have did 35 digit ecm on a 97 digit number a couple of days ago and that turned out to be way too much
could people post what rules they would use for switching to msieve
i have searched the forum but found nothing
thanks[/QUOTE]
Let the msieve binary do the ECM for you; it already has tuning that guarantees you won't spend too much time before switching to QS.

i do the ecm on multiple pcs so that is not possible
i looked at msieves code and found
[code]
static uint32 choose_max_digits(msieve_obj *obj, uint32 bits) {
/* choose the amount of work to do. We want the
chosen digit level to be a small fraction of what
QS and NFS would need */
uint32 max_digits = 15;
if (bits == 0)
return 0;
if (obj->flags & MSIEVE_FLAG_DEEP_ECM) {
if (bits > 220) {
if (bits < 280)
max_digits = 20;
else if (bits < 320)
max_digits = 25;
else if (bits < 360)
max_digits = 30;
else if (bits < 400)
max_digits = 35;
else
max_digits = 40;
}
}
return max_digits;
}
[/code]
this seems a bit low to me

[QUOTE=themaster;125976]i do the ecm on multiple pcs so that is not possible
i looked at msieves code and found
[code]
static uint32 choose_max_digits(msieve_obj *obj, uint32 bits) {
/* choose the amount of work to do. We want the
chosen digit level to be a small fraction of what
QS and NFS would need */
uint32 max_digits = 15;
if (bits == 0)
return 0;
if (obj->flags & MSIEVE_FLAG_DEEP_ECM) {
if (bits > 220) {
if (bits < 280)
max_digits = 20;
else if (bits < 320)
max_digits = 25;
else if (bits < 360)
max_digits = 30;
else if (bits < 400)
max_digits = 35;
else
max_digits = 40;
}
}
return max_digits;
}
[/code]
this seems a bit low to me[/QUOTE]

hmmmm... that's roughly what I am doing manually. (I am ECM'ing on multiple PCs too.)

Additionally I do some p-1 and p+1.

it probably is just that i am used to doing a lot more

I've heard a 2/7 rule of thumb mentioned before. For a 97-digit number, that would mean stopping ECM at 25 or 30 digits if you're trying to optimize computer time.

before this i used 1/3 but it often stretched

[QUOTE=jbristow;125994]I've heard a 2/7 rule of thumb mentioned before. For a 97-digit number, that would mean stopping ECM at 25 or 30 digits if you're trying to optimize computer time.[/QUOTE]AFAIK, the rulle of thumb is 2/9 for SNFS and 1/3 for GNFS. This latter rule is consistent with the 3/2 relative difficulties ROT for NFS.

Within reason, it doesn't much matter. If the factorization is non-trivial other considerations come into play, such as memory usage and communication overheads.

Paul

[quote=xilman;126007]AFAIK, the rulle of thumb is 2/9 for SNFS and 1/3 for GNFS. This latter rule is consistent with the 3/2 relative difficulties ROT for NFS.

Within reason, it doesn't much matter. If the factorization is non-trivial other considerations come into play, such as memory usage and communication overheads.

Paul[/quote]
what would u use for QS

[QUOTE=themaster;126039]what would u use for QS[/QUOTE]As I said, it doesn't much matter. QS is only competitive below 100 digits or thereabouts. I'd probably go to around 30 digits or so.


Paul

thanks
this should speed me up quite a bit so i can find more 100 digit RHPs