COMMAND LINE OPTIONS FOR MWRANK

Since December 1997, mwrank supports command-line options instead of
prompting the user.  All options have reasonable defaults.

List of command line options, their meaning and default values

[q, l, t take no parameters; the others take an integer parameter "n"]

-h	help		Displays a summary of this info and quits

-q	quiet mode flag	
			Suppresses the header information (including
			the date of compilation) which is otherwise output
			and should be included in any problem/bug reports).
			Default is off (i.e. not quiet).  Also
			suppresses prompting for curves.

-v n	verbosity level	
			Controls amount of output.  Range 0..3.
			Default=1.  Level 0 only outputs the rank.
			Use "-q -v 0" for minimal output, but note
			that if you also have "-c n" with nonzero n
			then you will cause a point search to be
			carried out, but you will not see its results!
			(Unless -o is used).
			Details of point search only shown if
			verbosity is > 1.

-o	output pari	Outputs a very terse summary of the results
			for use by PARI/GP with suitable interface.
			Format: 
			Either  [[r],[P1,P2,...,Pr]]
			where r is the rank and P1,...,Pr are r
			independent points;
			or      [[r,r'],[P1,P2,...,Pr]]
			where r and r' are lower and upper bounds
			on the rank and P1,...,Pr are r
			independent points;
			Can be used in addition to other output
			options (controlled by -v); for minimal useful
			output use "-q -v 0 -o"

-p n	precision (#dp)	
			Only relevant for the LiDIA multiprecision
			floating point versions.  Range 1..large,
			default 15.

-b n	height bound for quartic point search.  
			Range 1..15, default 10.   5 is large enough
			for many curves.

-x n	number of auxiliary primes used for syzygy sieving.  
			Range 0..,default 6.  Only relevant for curves
			with no 2-torsion.  Only worth increasing
			either for curves with large discriminant, or
			for curves with suspected large rank r, for
			which r+1 is a good value.

-l	points output flag.  
			Controls whether generating points are output.
			Defaults to value of "verbosity", so the only
			function is to turn this part of the output on
			when verbosity is 0 (i.e. -v 0 -l).

-t	quartic equivalence test flag.   
			For debugging only.  Default off.

-s      selmer_only     If set, does local tests on homogeneous spaces
			only, which can be much quicker for curves
			with 2-torsion.   NB for curves with no
			2-torsion this computes the 2-Selmer rank
			exactly;  for curves with 2-torsion it
			computes an upper bound for the rank based on
			various Selmer groups, possibly less than that
			from the 2-Selmer group itself.
			If unset (the default) then rational points
			are sought, to give a lower bound for the rank
			also. 

-d     skip_2nd_descent Only relevant for curves with 2-torsion;
			unset by default.  If set,  does no second
			descent either locally or globally, which in
			general gives a larger upper bound for the
			rank and a smaller lower bound.
			I recommend setting this if using mwrank with
			no multiprecision floating point arithmetic.

-S     saturation_bound (non-negative integer or -1) controls saturation
			0: do no saturation at all
			n: use n as upper bound for saturation primes
			-1: allow progam to determine upper bound
			autimatically (but that will be reduced to a
			default maximum of 100 if it is greater)

OBSOLETE option(s) which no longer have any effect:

-c n	height bound for curve point search.  
			This controls the point search after 2-descent.
			Range: -1,0,1..15 (default=0)
			(larger values take a very long time, and
			probably cause overflow owing to a technical
			problem which I have not yet fixed, so the
			program currently uses 15 if you give it any
			value > 15).
			If -1, then the program attempts to compute a
			suitable value which would guarantee that the
			full MW group was found, but this feature is
			not at all efficient, can easily lead to
			bounds >15 and hence problems, so the
			truncation at 15 is applied if necessary.
			If 0 (default) then no point search is done.

NB If this value is nonzero then you should have a nonzero value for
-v and/or the option -o switched on, otherwise the program carries out
a point search but you do not see its results, only the rank!