Pari/GP Reference Documentation |
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elladd ellak ellan ellap ellbil ellchangecurve ellchangepoint elleisnum elleta ellglobalred ellheight ellheightmatrix ellinit ellisoncurve ellj elllocalred elllseries ellorder ellordinate ellpointtoz ellpow ellrootno ellsigma ellsub elltaniyama elltors ellwp ellzeta ellztopoint | |

elladd(E,z1,z2) | |

sum of the points z1 and z2 on the elliptic curve corresponding to the vector E. The library syntax is | |

ellak(E,n) | |

computes the coefficient a_n of the
L-function of the elliptic curve E, i.e.in principle coefficients of a
newform of weight 2 assuming Taniyama-Weil conjecture (which is now
known to hold in full generality thanks to the work of Breuil,
Conrad, Diamond, Taylor and Wiles). E must be a
medium or long vector of the type given by The library syntax is | |

ellan(E,n) | |

computes the vector of the first n a_k
corresponding to the elliptic curve E. All comments in The library syntax is | |

ellap(E,p,{flag = 0}) | |

computes the a_p corresponding to the
elliptic curve E and the prime number p. These are defined by the
equation #E( If No checking is done that p is indeed prime. E must be a medium or long
vector of the type given by The library syntax is | |

ellbil(E,z1,z2) | |

if z1 and z2 are points on the elliptic curve E, this function computes the value of the canonical bilinear form on z1, z2: where The library syntax is | |

ellchangecurve(E,v) | |

changes the data for the elliptic curve E
by changing the coordinates using the vector The library syntax is | |

ellchangepoint(x,v) | |

changes the coordinates of the point or
vector of points x using the vector The library syntax is | |

elleisnum(E,k,{flag = 0}) | |

E being an elliptic curve as
output by The library syntax is | |

elleta(om) | |

returns the two-component row vector
[eta_1,eta_2] of quasi-periods associated to The library syntax is | |

ellglobalred(E) | |

calculates the arithmetic conductor, the global
minimal model of E and the global Tamagawa number c. Here E is an
elliptic curve given by a medium or long vector of the type given by
The library syntax is | |

ellheight(E,z,{flag = 0}) | |

global Néron-Tate height of
the point z on the elliptic curve E. The vector E must be a long vector
of the type given by The library syntax is | |

ellheightmatrix(E,x) | |

x being a vector of points, this
function outputs the Gram matrix of x with respect to the Néron-Tate
height, in other words, the (i,j) component of the matrix is equal to
The library syntax is | |

ellinit(E,{flag = 0}) | |

computes some fixed data concerning the
elliptic curve given by the five-component vector E, which will be
essential for most further computations on the curve. The result is a
19-component vector E (called a long vector in this section), shortened
to 13 components (medium vector) if a_1,a_2,a_3,a_4,a_6,b_2,b_4,b_6,b_8,c_4,c_6,Delta,j. In particular, the discriminant is E[12] (or The other six components are only present if
E[15] ( E[17] and E[18] are the corresponding values eta_1 and eta_2 such
that eta_1omega_2-eta_2omega_1 = iPi, and both can be retrieved by
typing Finally, E[19] (
E[15] is equal to the square of the u-value, in the notation of Tate. E[16] is the u-value itself, if it belongs to E[17] is the value of Tate's q for the curve E.
E[18] ( For all other base fields or rings, the last six components are arbitrarily set equal to zero (see also the description of member functions related to elliptic curves at the beginning of this section). The library syntax is | |

ellisoncurve(E,z) | |

gives 1 (i.e.true) if the point z is on the elliptic curve E, 0 otherwise. If E or z have imprecise coefficients, an attempt is made to take this into account, i.e.an imprecise equality is checked, not a precise one. The library syntax is | |

ellj(x) | |

elliptic j-invariant. x must be a complex number with positive imaginary part, or convertible into a power series or a p-adic number with positive valuation. The library syntax is | |

elllocalred(E,p) | |

calculates the Kodaira type of the
local fiber of the elliptic curve E at the prime p.
E must be given by a medium or
long vector of the type given by 1 means good reduction (type I_0), 2, 3 and 4 mean types II, III and IV respectively, 4+nu with nu > 0 means type I_nu; finally the opposite values -1, -2, etc.refer to the starred types I_0^*, II^*, etc. The third component v is itself a vector [u,r,s,t] giving the coordinate changes done during the local reduction. Normally, this has no use if u is 1, that is, if the given equation was already minimal. Finally, the last component c is the local Tamagawa number c_p. The library syntax is | |

elllseries(E,s,{A = 1}) | |

E being a medium or long vector
given by Note that if the conductor of the curve is large, say greater than 10^{12}, this function will take an unreasonable amount of time since it uses an O(N^{1/2}) algorithm. The library syntax is | |

ellorder(E,z) | |

gives the order of the point z on the elliptic
curve E if it is a torsion point, zero otherwise. In the present version
The library syntax is | |

ellordinate(E,x) | |

gives a 0, 1 or 2-component vector containing the y-coordinates of the points of the curve E having x as x-coordinate. The library syntax is | |

ellpointtoz(E,z) | |

if E is an elliptic curve with coefficients
in If E has coefficients in The library syntax is | |

ellpow(E,z,n) | |

computes n times the point z for the
group law on the elliptic curve E. Here, n can be in The library syntax is | |

ellrootno(E,{p = 1}) | |

E being a medium or long vector given
by The library syntax is | |

ellsigma(E,z,{flag = 0}) | |

value of the Weierstrass sigma
function of the lattice associated to E as given by If If | |

ellsub(E,z1,z2) | |

difference of the points z1 and z2 on the elliptic curve corresponding to the vector E. The library syntax is | |

elltaniyama(E) | |

computes the modular parametrization of the
elliptic curve E, where E is given in the (long or medium) format output
by The library syntax is | |

elltors(E,{flag = 0}) | |

if E is an elliptic curve
[t,v1,v2], where
t is the order of the torsion group,
v1
gives the structure of the torsion group as a product of cyclic groups
(sorted by decreasing order), and
v2 gives generators for these cyclic
groups. E must be a long vector as output by
ellinit.
Here, the torsion subgroup is isomorphic to If If The library syntax is | |

ellwp(E,{z = x},{flag = 0}) | |

Computes the value at z of the Weierstrass wp function attached to the
elliptic curve E as given by If z is omitted or is a simple variable, computes the Optional The library syntax is | |

ellzeta(E,z) | |

value of the Weierstrass zeta function of the
lattice associated to E as given by The library syntax is | |

ellztopoint(E,z) | |

E being a long vector, computes the
coordinates [x,y] on the curve E corresponding to the complex number z.
Hence this is the inverse function of The library syntax is | |