# Cython interface to Cremona’s eclib library (also known as mwrank)¶

Cython interface to Cremona’s eclib library (also known as mwrank)

EXAMPLES:

sage: from sage.libs.mwrank.mwrank import _Curvedata, _mw
sage: c = _Curvedata(1,2,3,4,5)

sage: print c
[1,2,3,4,5]
b2 = 9       b4 = 11         b6 = 29         b8 = 35
c4 = -183           c6 = -3429
disc = -10351       (# real components = 1)
#torsion not yet computed

sage: t= _mw(c)
sage: t.search(10)
sage: t
[[1:2:1]]

sage.libs.mwrank.mwrank.get_precision()

Returns the working floating point precision of mwrank.

OUTPUT:

(int) The current precision in decimal digits.

EXAMPLE:

sage: from sage.libs.mwrank.mwrank import get_precision
sage: get_precision()
50

sage.libs.mwrank.mwrank.initprimes(filename, verb=False)

Initialises mwrank/eclib’s internal prime list.

INPUT:

• filename (string) – the name of a file of primes.
• verb (bool: default False) – verbose or not?

EXAMPLES:

sage: file = os.path.join(SAGE_TMP, 'PRIMES')
sage: open(file,'w').write(' '.join([str(p) for p in prime_range(10^7,10^7+20)]))
sage: mwrank_initprimes(file, verb=True)
Computed 78519 primes, largest is 1000253
finished reading primes from file ...
Extra primes in list: 10000019

sage: mwrank_initprimes("x" + file, True)
Traceback (most recent call last):
...
IOError: No such file or directory: ...

sage.libs.mwrank.mwrank.set_precision(n)

Sets the working floating point precision of mwrank.

INPUT:

• n (int) – a positive integer: the number of decimal digits.

OUTPUT:

None.

EXAMPLE:

sage: from sage.libs.mwrank.mwrank import set_precision
sage: set_precision(50)


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