1	COMMAND LINE OPTIONS FOR MWRANK
2
3Since December 1997, mwrank supports command-line options instead of
4prompting the user.  All options have reasonable defaults.
5
6List of command line options, their meaning and default values (set in options.h)
7
8[q, l, t take no parameters; the others take an integer parameter "n"]
9
10-h	help		Displays a summary of this info and quits
11
12-q	quiet mode flag
13			Suppresses the header information (including
14			the date of compilation) which is otherwise output
15			and should be included in any problem/bug reports).
16			Default is off (i.e. not quiet).  Also
17			suppresses prompting for curves
18
19-v n	verbosity level
20			Controls amount of output.  Range 0..3.
21			Default=1.  Level 0 only outputs the rank.
22			Use "-q -v 0" for minimal output, but note
23			that if you also have "-c n" with nonzero n
24			then you will cause a point search to be
25			carried out, but you will not see its results!
26			(Unless -o is used).
27			Details of point search only shown if
28			verbosity is > 1.
29
30-o	output pari	Outputs a very terse summary of the results
31			for use by PARI/GP with suitable interface.
32			Format:
33			Either  [[r],[P1,P2,...,Pr]]
34			where r is the rank and P1,...,Pr are r
35			independent points;
36			or      [[r,r'],[P1,P2,...,Pr]]
37			where r and r' are lower and upper bounds
38			on the rank and P1,...,Pr are r
39			independent points;
40			Can be used in addition to other output
41			options (controlled by -v); for minimal useful
42			output use "-q -v 0 -o"
43
44-p n	precision (#bits)
45			Only relevant for the multiprecision
46			floating point version.  Range 1..large,
47			default 50.  This is bit precision.
48			Stringly recommended to increase for curves
49			with 2-torsion where a second descent is used
50			since then the reduction applied to second
51			descent quartics is more effective.
52
53-b n	height bound for quartic point search.
54			Range 1..15, default 10.
55
56-x n	number of auxiliary primes used for syzygy sieving.
57			Range 0..,default 15.  Only relevant for curves
58			with no 2-torsion.  Worth increasing
59			either for curves with large discriminant, or
60			for curves with suspected large rank r, for
61			which r+1 or r+2 are suitable values.
62
63-l	points output flag.
64			Controls whether generating points are output.
65			Defaults to value of "verbosity", so the only
66			function is to turn this part of the output on
67			when verbosity is 0 (i.e. -v 0 -l).
68
69-t	quartic equivalence test flag.
70			For debugging only.  Default off.
71
72-s      selmer_only     If set, does local tests on homogeneous spaces
73			only, which can be much quicker for curves
74			with 2-torsion.   NB for curves with no
75			2-torsion this computes the 2-Selmer rank
76			exactly;  for curves with 2-torsion it
77			computes an upper bound for the rank based on
78			various Selmer groups, possibly less than that
79			from the 2-Selmer group itself.
80			If unset (the default) then rational points
81			are sought, to give a lower bound for the rank
82			also.
83
84-d     skip_2nd_descent Only relevant for curves with 2-torsion;
85			unset by default.  If set,  does no second
86			descent either locally or globally, which in
87			general gives a larger upper bound for the
88			rank and a smaller lower bound.
89			I recommend setting this if using mwrank with
90			no multiprecision floating point arithmetic.
91
92-S     saturation_bound (non-negative integer or -1) controls saturation
93			0: do no saturation at all
94			n: use n as upper bound for saturation primes
95			-1: allow progam to determine upper bound
96			automatically (but that will be reduced to a
97			default maximum of 100 if it is greater)
98
99Last update: 2016-01-02
100