How to Use Prime95: Advanced Menu

# ADVANCED MENU

##### Applies To

Test | Priority
Time | Affinity
P-1 | Manual Communication
ECM | Unreserve Exponent
Round off checking | Quit GIMPS

You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices.

## Test

The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 5 and 79300000.

## Time

The Time choice can be used to see how long each iteration of a Lucas-Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations.

## P-1

The P-1 choice lets you factor Mersenne numbers using the P-1 method of factoring. There is presently no web site which tells you how much P-1 factoring has already been done on exponents. You can also edit the worktodo.ini file directly. For example:

Pminus1=751001,1000000,0,0,0

The first value is the exponent. The second value is bound #1. The third value is bound #2. The fourth value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The fifth value is no longer used.

##

## ECM

The ECM choice lets you factor Mersenne numbers using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web pages.

Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@alum.mit.edu - PrimeNet does not support ECM factoring. WARNING: ECM does not adhere to the memory limits specified in the Options/CPU dialog box. ECM requires a minimum of 192 times the FFT size. Thus, ECM factoring of F20 which uses a 64K FFT will use a minimum of 192 * 64K or 12MB of memory. You can also edit the worktodo.ini file directly. For example:

ECM=751,3000000,0,100,0,0,0,0

The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is no longer used. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The eighth value is no longer used.

## Round Off

Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on.

## Priority

The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without a screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason.

## Affinity

Dual processor machines can also improve performance by setting processor affinity. Use the Advanced/Affinity dialog box to do this.

## Manual Communication

The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice).

## Unreserve Exponent

The Unreserve Exponent choice lets you tell the server to unreserved an exponent you have been assigned. You might do this if a second computer you had been running GIMPS on died or if you had been assigned an exponent of one work type (such as a first-time-test) and now you have switched to another work type (such as 10,000,000 digit numbers). Any work you have done on the unreserved exponent will be lost.

## Quit

The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinished work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting.