Each column in the matrix corresponds to a number in the factor base     
less than some bound B.  Each row corresponds to a smooth number (able   
to be completely factored over the factor base).  Each value in a row    
binary vector corresponds to the exponent of the factor base mod 2.      
For example:                                                             
                                                                         
    factor base: 2 7 23                                                  
    smooth numbers: 46, 28, 322                                          
    2^1       * 23^1 = 46                                                
    2^2 * 7^1        = 28                                                
    2^1 * 7^1 * 23^1 = 322                                               
    Matrix:                                                              
        101                                                              
        010                                                              
        111                                                              
                                                                         
A solution to the matrix is considered to be a set of rows which when    
combined in GF2 produce a null vector. Thus, if you multiply each of     
the smooth numbers which correspond to that particular set of rows you   
will get a number with only even exponents, making it a perfect          
square. In the above example you can see that combining the 3 vectors    
results in a null vector and, indeed, it is a perfect square: 644^2.     
                                                                         
Problem.A: A GF(2) matrix constructed from the exponents of the          
factorization of the smooth numbers over the factor base. A solution of  
this matrix is a kernel (nullspace). Such a solution has a 1/2 chance of 
being a factorization of N.                                              
                                                                         
Problem.aux.factor_base: The factor base used. factor_base(j) corresponds
to column j of the matrix. Note that a given column may or may not have  
nonzero elements in the matrix.                                          
                                                                         
Problem.aux.smooth_number: The smooth numbers, smooth over the factor    
base.  smooth_number(i) corresponds to row i of the matrix.              
                                                                         
Problem.aux.solution: A sample solution to the matrix. Combine, in GF(2) 
the rows with these indicies to produce a solution to the matrix with the
additional property that it factors N (a matrix solution only has 1/2    
probability of factoring N).                                             
                                                                         
Problem specific information:                                            
                                                                         
n = 73363722971930954428433124842779099222294372095286387 (176-bits)     
passes primality test, n is composite, continuing...                     
1) Initial bound: 180000, pi(180000) estimate: 14875,                    
    largest found: 162359 (actual bound)                                 
2) Number of quadratic residues estimate: 9918, actual number found: 7431
3) Modular square roots found: 14862(2x residues)                        
4) Constructing smooth number list [sieving] (can take a while)...       
Sieving for: 7441                                                        
5. Constructing a matrix of size: 7441x7432                              
Set a total of 82270 exponents, with 3725 negatives                      
Matrix solution found with: 2983 combinations                            
Divisor: 236037985789994529800050193 (probably prime)                    
Divisor: 310813205452462332837525059 (probably prime)