[Ecm-dev] Proposal from George. Literally.
woltman at alum.mit.edu
Mer 11 Mai 16:26:16 CEST 2005
I've hacked at the code and am ready to start integrating it with
GMP-ECM. I won't
have time to work on it today, but tomorrow I'll download mingw and see if
I can get
the two to link together.
A few minor issues came up.
1) In case of user interrupt, I want to return both x and z to write to a
Normalizing the coordinate, especially during system shutdown, could take
for large numbers.
2) I've added an option to force the code to do stage 1 for the 3 multiply
reduction case (b <> 2). While it won't make sense for Cunningham numbers, it
might make sense as numbers get very large. I don't expect you'll use this
3) I've added a way to pass in an arbitrary number for the 3 multiply
generic reduction case (set k=b=n=c=0). Again, probably for use at a later
date (or never).
/* Return codes */
#define ES1_SUCCESS 0 /* Success, but no factor */
#define ES1_FACTOR_FOUND 1 /* Success, factor found */
#define ES1_CANNOT_DO_IT 2 /* This k,b,n,c cannot be handled */
#define ES1_MEMORY 3 /* Out of memory */
#define ES1_INTERRUPT 4 /* Execution interrupted */
#define ES1_CANNOT_DO_QUICKLY 5 /* Requires 3-multiply reduction */
#define ES1_HARDWARE_ERROR 6 /* An error was detected, most */
/* likely a hardware error. */
/* Option codes */
#define ES1_DO_SLOW_CASE 0x1 /* Set this if ecmStage1 should */
/* do slow 3-multiply reduction
Input number (3 possibilities):
1) k,b,n,c set and num_being_factored_array = NULL. k*b^n+c is factored.
2) k,b,n,c zero and num_being_factored_array set. num_being_factored is
worked on using generic 3-multiply reduction
3) k,b,n,c set and num_being_factored_array set. num_being_factored is
worked on - it must be a factor of k*b^n+c.
A_array, B1 are required
B1_done is optional. Use it to resume a stage 1 calculation.
x_array, z_array is the starting coordinate. If z_array is not given, then
z is assumed to be one.
stop_check_proc is optional
options are defined above
x_array is set to normalized coordinate
On factor found:
x_array is set to the factor found
B1_done is set to the last prime below B1 that was processed
x_array and z_array are set to the current coordinate. The (x,z) coordinate
is not normalized because it will be slow for large numbers. This is
unacceptable during system shutdown. Caller must allocate x and z arrays
large enough to hold any k*b^n+c value.
int ecmStage1 (
double k, /* K in K*B^N+C */
unsigned long b, /* B in K*B^N+C */
unsigned long n, /* N in K*B^N+C */
signed long c, /* C in K*B^N+C */
unsigned long *num_being_factored_array, /* Number to factor */
unsigned long num_being_factored_array_len,
unsigned long B1, /* Stage 1 bound */
unsigned long *B1_done, /* Stage 1 that is already done */
unsigned long *A_array, /* A - caller derives it from sigma */
unsigned long A_array_len,
unsigned long *x_array, /* X coordinate */
unsigned long *x_array_len,
unsigned long *z_array, /* Z coordinate */
unsigned long *z_array_len,
int (*stop_check_proc)(void),/* Ptr to proc that returns TRUE */
/* if user interrupts processing */
unsigned long options)
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