an expression parser for manual tests?

[ixfd64]

For the "P-1..." and "ECM..." options, users can input an expression of the form k * bⁿ ± c. However, it requires the user to input values into four separate fields. It seems a bit clumsy in today's standards. Therefore, I'm proposing a feature that will automatically parse expressions of certain forms.

As a proof of concept, I've written a simple Python program that processes expressions of the form k * bⁿ ± c and bⁿ ± c (in which case k = 1). I don't imagine it being to hard to add a similar feature to Prime95.

import re

def main():
    
    # it's probably possible to use just one regular expression
    pattern_full = "^(\d+)\s*\*\s*\d+\s*\^\s*\d+\s*[\+-]\s*\d+"
    pattern_no_prefix = "(\d+)\s*\^\s*(\d+)\s*([\+-])\s*(\d+)"
    
    v1 = 1
    
    def print_vars(k = 1, b = 1, p = 1, c = 0):
        out = "k = " + str(k) + ", b = " + str(b) + ", n = " + str(p) + ", c = " + str(c)
        print out
    
    while True:
        raw_expr = raw_input("Enter expression (\"q\" to quit): ")
        expr = raw_expr.strip()
        if expr == "q":
            break
        f = re.findall(pattern_full, expr)
        np = re.findall(pattern_no_prefix, expr)
        if not f == []:
            v1 = int(f[0])
        if np == []:
            print "Invalid expression"
        else:
            v2 = int(np[0][0])
            v3 = int(np[0][1])
            v4 = int(np[0][3])
            if np[0][2] == "-":
                v4 = -v4
            print_vars(v1, v2, v3, v4)

if __name__ == "__main__":
    main()

Sample output:

Enter expression ("q" to quit): 2^57885161-1
k = 1, b = 2, n = 57885161, c = -1
Enter expression ("q" to quit): 2^1024+1
k = 1, b = 2, n = 1024, c = 1
Enter expression ("q" to quit): 19249 *2^ 13018586 + 1
k = 19249, b = 2, n = 13018586, c = 1
Enter expression ("q" to quit): q

[Dubslow]

Good luck using regular expressions in C.

[rogue]

If you want to PRP, then use pfgw. For P+1/P-1/ecm, use GMP-ECM with gwnum. In fact, isn't there a GPU version of GMP-ECM?

[ET_]

Originally Posted by rogue

If you want to PRP, then use pfgw. For P+1/P-1/ecm, use GMP-ECM with gwnum. In fact, isn't there a GPU version of GMP-ECM?

There is, with some limitations.

- The number to test should have less than 1017 bits.
- The number of curves to do is locked to reach the best GPU performance (512 curves on my GTX580, 224 on lower cards).

Luigi)