runtime error in Update

[mhaluk]

Dear Chris, Thank you for this package! I downloaded the packages and tried your example. I got the following error message:

Magma V2.21-2     Wed Nov  1 2017 21:23:14  [Seed = 848384097]
Type ? for help.  Type <Ctrl>-D to quit.
> 
> 
> AttachSpec("Desktop/MAGMA/ExactpAdics/spec");
> AttachSpec("Desktop/MAGMA/Genus2Conductor/spec_ExactpAdics");
> 
> 
> R<x> := PolynomialRing(Rationals()); 
> C := HyperellipticCurve(R![-30, 0, -37, 0, -15, 0, -2], R![]);
> 
> Conductor_Genus2(C);

Conductor_Genus2(
    C: Hyperelliptic Curve defined by y^2 = -2*x^6 - 15*x^4 - 37*x^...
)
EvenConductorExponent_Genus2(
    C: Hyperelliptic Curve defined by y^2 = -2*x^6 - 15*x^4 - 37*x^...
)
evencondexp(
    C: Hyperelliptic Curve defined by y^2 = -2*x^6 - 15*x^4 - 37*x^...,
    p: 2
)
evencondexpdata(
    C: Hyperelliptic Curve defined by y^2 = -2*x^6 - 15*x^4 - 37*x^...,
    p: 2
)
find_3torsion(
    f: -8*x^6 - 60*x^4 - 148*x^2 - 120,
    p: Ideal of Integer Ring generated by 2
)
go(
    r:     rec<recformat<success, err, seed, moebius, groebner_basis, K...
)
Roots(
    f: (1 + O($.1))*$.1^8 + ($.1^28 + O($.1^29))*$.1^7 + ($.1^32 + ...
)
ExactpAdics_ExecutePrecisionStrategy(
    cb: function(pr) ... end function,
    strategy: [* 100, <limit, Infinity>, <randomize, true>, <double> *]
)
[/Desktop/MAGMA/ExactpAdics/Factorization.mag:214](
    pr: 100
)
IsHenselLiftable(
    f: (1 + O($.1))*$.1^8 + ($.1^28 + O($.1^29))*$.1^7 + ($.1^32 + ...,
    x: $.1^12 + O($.1^13)
)
Approximation(
    f: ($.1^376 + O($.1^377))*$.1^8 + ($.1^334 + O($.1^335))*$.1^7 ...,
    apr: 1
)
Evaluate(
    g: Getter
)
satisfy_deps_list(
    ds:     [* [* ($.1^376 + O($.1^377))*$.1^8 + ($.1^334 + O($.1^335))*...,
    maxid: Infinity
)
deps_satisfy(
    deps: Associative Array with index universe Integer Ring
)
dep_doUpdate(
    d:     rec<recformat<id, x, apr, st, g, childids> |  id := 180, x :...,
    done: false
)
[/Desktop/MAGMA/ExactpAdics/Getter.mag:346](
    st:     [* [* [* true, Getter, [* false, false, false *] *], true, $...,
    val: [* $.1^8 + (((12814*$.1 + 112851)*$.1^3 + (138554*$.1 + 2589...
)
callList(
    f: function(xf, xx) ... end function,
    x: [* $.1^8 + (((12814*$.1 + 112851)*$.1^3 + (138554*$.1 + 2589...,
    n: 2
)
[/Desktop/MAGMA/ExactpAdics/Getter.mag:330](
    f: function(xf, xx) ... end function,
    x: [* $.1^8 + (((12814*$.1 + 112851)*$.1^3 + (138554*$.1 + 2589...
)
[/Desktop/MAGMA/ExactpAdics/ExactpAdics.mag:3118](
    xf: $.1^8 + (((12814*$.1 + 112851)*$.1^3 + (138554*$.1 + 258986)...,
    xx: ((123558*$.1 + 109812)*$.1^3 + (48754*$.1 + 35952)*$.1^2 + (...
)
In file "/Desktop/MAGMA/ExactpAdics/ExactpAdics.mag", line 
3119, column 13:
>>       Update(z, Evaluate(xf, Parent(xf).1 + xx));^M
               ^
Runtime error in 'Update': inconsistent

thanks, Haluk

[cjdoris]

@mhaluk It looks like you are using a reasonably old version of Magma, and I know there lots of issues with p-adics in ramified extensions (in Magma itself, so nothing I can fix!), although some have been fixed more recently. Please do the following:

• SetDebugOnError(true);
• Repeat the above steps to reproduce the bug
• In the debugger, type p Parent(f`approximation)

I suspect that the field that gets printed out is a ramified one?

[mhaluk]

Thanks Chris.I must be a version issue as you predict. The debug indicates the field to be ramified as you guessed, here it is:

debug> p Parent(f`approximation); Univariate Polynomial Ring over Totally ramified extension defined by a map over Unramified extension defined by a map over pAdicField(2)