
// Make newform 546.2.bk.b in Magma, downloaded from the LMFDB on 19 April 2024.
// To make the character of type GrpDrchElt, type "MakeCharacter_546_bk();"
// To make the character of type GrpDrchElt with Codomain the HeckeField, type "MakeCharacter_546_bk_Hecke();"
// To make the coeffs of the qexp of the newform in the Hecke field type "qexpCoeffs();"
// To make the newform (type ModFrm), type "MakeNewformModFrm_546_2_bk_b();".
// This may take a long time!  To see verbose output, uncomment the SetVerbose lines below.
// The precision argument determines an initial guess on how many Fourier coefficients to use.
// This guess is increased enough to uniquely determine the newform.
// To make the Hecke irreducible modular symbols subspace (type ModSym)
// containing the newform, type "MakeNewformModSym_546_2_bk_b();".
// This may take a long time!  To see verbose output, uncomment the SetVerbose line below.
// The default sign is -1.  You can change this with the optional parameter "sign".
function ConvertToHeckeField(input: pass_field := false, Kf := [])
    if not pass_field then
        poly := [49, 0, 21, 0, 270, 0, -247, 0, 90, 0, -15, 0, 1];
        Kf := NumberField(Polynomial([elt : elt in poly]));
        AssignNames(~Kf, ["nu"]);
    end if;
    Rf_num := [[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [1505, 0, 5950, 0, -3874, 0, 906, 0, -83, 0, 2, 0], [3290, 0, 3931, 0, 2536, 0, -2063, 0, 406, 0, -25, 0], [3227, 0, 2977, 0, -3609, 0, 335, 0, 151, 0, -29, 0], [0, -1442, 0, 5950, 0, -3874, 0, 906, 0, -83, 0, 2], [0, -56623, 0, 61188, 0, -17245, 0, 404, 0, 397, 0, -40], [-14175, 0, 902, 0, 6675, 0, -3540, 0, 723, 0, -58, 0], [0, 151641, 0, -156047, 0, 69487, 0, -15653, 0, 1651, 0, -55], [8176, 0, -30699, 0, 23780, 0, -8321, 0, 1378, 0, -89, 0], [0, -45465, 0, -88545, 0, 98967, 0, -40029, 0, 7109, 0, -501], [0, -75957, 0, -82129, 0, 94100, 0, -33779, 0, 5358, 0, -332]];
    Rf_basisdens := [1, 1, 2947, 5894, 5894, 2947, 41258, 5894, 41258, 5894, 41258, 20629];
    Rf_basisnums := ChangeUniverse([[z : z in elt] : elt in Rf_num], Kf);
    Rfbasis := [Rf_basisnums[i]/Rf_basisdens[i] : i in [1..Degree(Kf)]];
    inp_vec := Vector(Rfbasis)*ChangeRing(Transpose(Matrix([[elt : elt in row] : row in input])),Kf);
    return Eltseq(inp_vec);
end function;


// To make the character of type GrpDrchElt, type "MakeCharacter_546_bk();"
function MakeCharacter_546_bk()
    N := 546;
    order := 6;
    char_gens := [365, 157, 379];
    v := [6, 4, 3];
    // chi(gens[i]) = zeta^v[i]
    assert UnitGenerators(DirichletGroup(N)) eq char_gens;
    F := CyclotomicField(order);
    chi := DirichletCharacterFromValuesOnUnitGenerators(DirichletGroup(N,F),[F|F.1^e:e in v]);
    return MinimalBaseRingCharacter(chi);
end function;

// To make the character of type GrpDrchElt with Codomain the HeckeField, type "MakeCharacter_546_bk_Hecke();"
function MakeCharacter_546_bk_Hecke(Kf)
    N := 546;
    order := 6;
    char_gens := [365, 157, 379];
    char_values := [[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [-1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0], [-1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]];
    assert UnitGenerators(DirichletGroup(N)) eq char_gens;
    values := ConvertToHeckeField(char_values : pass_field := true, Kf := Kf); // the value of chi on the gens as elements in the Hecke field
    F := Universe(values);// the Hecke field
    chi := DirichletCharacterFromValuesOnUnitGenerators(DirichletGroup(N,F),values);
    return chi;
end function;


function ExtendMultiplicatively(weight, aps, character)
    prec := NextPrime(NthPrime(#aps)) - 1; // we will able to figure out a_0 ... a_prec
    primes := PrimesUpTo(prec);
    prime_powers := primes;
    assert #primes eq #aps;
    log_prec := Floor(Log(prec)/Log(2)); // prec < 2^(log_prec+1)
    F := Universe(aps);
    FXY<X, Y> := PolynomialRing(F, 2);
    // 1/(1 - a_p T + p^(weight - 1) * char(p) T^2) = 1 + a_p T + a_{p^2} T^2 + ...
    R<T> := PowerSeriesRing(FXY : Precision := log_prec + 1);
    recursion := Coefficients(1/(1 - X*T + Y*T^2));
    coeffs := [F!0: i in [1..(prec+1)]];
    coeffs[1] := 1; //a_1
    for i := 1 to #primes do
        p := primes[i];
        coeffs[p] := aps[i];
        b := p^(weight - 1) * F!character(p);
        r := 2;
        p_power := p * p;
        //deals with powers of p
        while p_power le prec do
            Append(~prime_powers, p_power);
            coeffs[p_power] := Evaluate(recursion[r + 1], [aps[i], b]);
            p_power *:= p;
            r +:= 1;
        end while;    
    end for;
    Sort(~prime_powers);
    for pp in prime_powers do
        for k := 1 to Floor(prec/pp) do
            if GCD(k, pp) eq 1 then
                coeffs[pp*k] := coeffs[pp]*coeffs[k];
            end if;
        end for;
    end for;
    return coeffs;
end function;


function qexpCoeffs()
    // To make the coeffs of the qexp of the newform in the Hecke field type "qexpCoeffs();"
    weight := 2;
    raw_aps := [[0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0], [0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0], [0, 0, 0, 0, 0, 0, 1, 0, 0, 0, -1, 1], [0, 1, 0, 0, 0, 1, -2, 0, 1, 0, 2, 1], [1, -1, 0, 0, 0, -2, 1, -1, 0, 0, -1, 0], [-1, 0, 2, 2, 1, 0, 0, 0, 0, 0, 0, 0], [0, -4, 0, 0, 0, -2, 1, 0, 0, 0, -2, 0], [2, 0, 2, -2, -4, 0, 0, 0, 0, -1, 0, 0], [1, 0, 0, -1, 1, 0, 0, -3, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 4, 0, 0, 0, -4, 0], [0, -2, 0, 0, 0, -1, 0, 0, 0, 0, -1, 0], [0, 3, 0, 0, 0, 4, -3, 0, 0, 0, 1, 2], [2, 0, 0, -2, 2, 0, 0, 0, 0, 0, 0, 0], [0, -4, 0, 0, 0, -2, -1, 0, -4, 0, -2, 0], [0, 0, -3, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, -5, 0, 0, 0, -3, 4, 0, -4, 0, -5, -4], [0, 0, -2, 1, 2, 0, 0, 0, 0, -2, 0, 0], [0, 6, 0, 0, 0, 2, -3, 0, 4, 0, 5, 4], [0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 3, 1], [0, -1, 0, 0, 0, -5, 9, 0, -3, 0, -7, -3], [6, 0, -2, -2, -4, 0, 0, 0, 0, -4, 0, 0], [0, 4, 0, 0, 0, 7, -4, 0, 0, 0, 10, 1], [0, -2, 0, 0, 0, -1, 8, 0, 0, 0, -1, 0], [0, -1, 0, 0, 0, 1, 1, 0, 0, 0, 7, -3], [-1, 0, -7, 2, 1, 0, 0, -1, 0, -1, 0, 0], [-4, 0, 12, -4, -8, 0, 0, 0, 0, -4, 0, 0], [0, 0, 4, -2, -4, 0, 0, 0, 0, 4, 0, 0], [0, 0, 0, 0, 0, -4, 12, 0, -2, 0, -10, -2], [-1, 0, 0, 4, -4, 0, 0, 7, 0, 0, 0, 0], [-4, 0, 0, 5, -5, 0, 0, 2, 0, 0, 0, 0], [11, 0, -5, -3, -6, 0, 0, 0, 0, -6, 0, 0], [0, -3, 0, 0, 0, -1, -9, 0, -2, 0, 8, -2], [2, 0, 0, 2, -2, 0, 0, 1, 0, 0, 0, 0], [0, 4, 0, 0, 0, 2, 0, 0, 3, 0, 2, 0], [0, 5, 0, 0, 0, 5, -12, 0, 5, 0, 12, 5], [-8, 0, -15, 16, 8, 0, 0, 5, 0, 5, 0, 0], [0, 2, 0, 0, 0, 1, 9, 0, 3, 0, 1, 0], [0, 8, 0, 0, 0, 13, -8, 0, 0, 0, 7, 3], [-8, 0, 6, 1, 2, 0, 0, 0, 0, 9, 0, 0], [2, 0, 10, -4, -2, 0, 0, -4, 0, -4, 0, 0], [-11, 0, 0, -1, 1, 0, 0, -4, 0, 0, 0, 0], [6, 0, -2, -2, -4, 0, 0, 0, 0, 2, 0, 0], [0, -5, 0, 0, 0, -5, -1, 0, -5, 0, 1, -5], [0, -3, 0, 0, 0, -3, 3, 0, 0, 0, -13, -3], [-3, 0, 9, 6, 3, 0, 0, -6, 0, -6, 0, 0], [10, 0, 0, 2, -2, 0, 0, -5, 0, 0, 0, 0], [0, 3, 0, 0, 0, 3, -3, 0, 0, 0, -14, 3], [0, -4, 0, 0, 0, 0, 8, 0, -2, 0, -10, -2], [0, 0, 0, 0, 0, 0, -8, 0, 4, 0, 0, 0], [19, 0, -11, -4, -8, 0, 0, 0, 0, -1, 0, 0], [0, -10, 0, 0, 0, -15, 10, 0, 0, 0, -9, -5], [0, -6, 0, 0, 0, -2, 6, 0, -4, 0, -8, -4], [6, 0, 0, -8, 8, 0, 0, -6, 0, 0, 0, 0], [-12, 0, 8, 2, 4, 0, 0, 0, 0, 4, 0, 0], [0, 0, 8, 0, 0, 0, 0, -5, 0, -5, 0, 0], [-3, 0, 0, 6, 3, 0, 0, -11, 0, -11, 0, 0], [0, 0, 0, 0, 0, 0, 11, 0, 5, 0, 0, 0], [5, 0, -6, -10, -5, 0, 0, 2, 0, 2, 0, 0], [0, -4, 0, 0, 0, -8, 4, 0, 0, 0, 12, 0], [0, 0, -10, 0, 0, 0, 0, 3, 0, 3, 0, 0], [0, -1, 0, 0, 0, -5, 1, 0, 0, 0, 17, 3], [0, -2, 0, 0, 0, 2, 2, 0, 0, 0, -9, -6], [-2, 0, 0, 4, 2, 0, 0, 7, 0, 7, 0, 0], [19, 0, -17, -1, -2, 0, 0, 0, 0, -3, 0, 0], [0, 12, 0, 0, 0, 6, -10, 0, 4, 0, 6, 0], [0, -10, 0, 0, 0, -5, -4, 0, -15, 0, -5, 0], [-3, 0, 0, 4, -4, 0, 0, -4, 0, 0, 0, 0], [-1, 0, -25, 2, 1, 0, 0, 4, 0, 4, 0, 0], [0, -5, 0, 0, 0, -4, 5, 0, 0, 0, -11, -6], [0, 12, 0, 0, 0, 8, -2, 0, 10, 0, 4, 10], [0, -14, 0, 0, 0, -7, 0, 0, 1, 0, -7, 0], [-2, 0, 0, 4, 2, 0, 0, 10, 0, 10, 0, 0], [-1, 0, 5, -2, -4, 0, 0, 0, 0, -11, 0, 0], [0, -2, 0, 0, 0, -2, 2, 0, 0, 0, 6, -2], [0, 10, 0, 0, 0, 5, 4, 0, 5, 0, 5, 0], [-7, 0, -4, 14, 7, 0, 0, 7, 0, 7, 0, 0], [0, 2, 0, 0, 0, 1, -10, 0, -6, 0, 1, 0], [0, 14, 0, 0, 0, 7, -6, 0, 4, 0, 7, 0], [0, -5, 0, 0, 0, -5, 11, 0, -5, 0, -11, -5], [-16, 0, 0, -4, 4, 0, 0, -8, 0, 0, 0, 0], [0, 5, 0, 0, 0, 10, -5, 0, 0, 0, 9, 0], [0, -6, 0, 0, 0, 4, 8, 0, -1, 0, -13, -1], [-1, 0, 0, 4, -4, 0, 0, -6, 0, 0, 0, 0], [-5, 0, 3, 1, 2, 0, 0, 0, 0, 12, 0, 0], [-5, 0, 11, -3, -6, 0, 0, 0, 0, -6, 0, 0], [0, -2, 0, 0, 0, -8, 2, 0, 0, 0, -16, 4], [0, 16, 0, 0, 0, 8, 4, 0, -3, 0, 8, 0], [0, -10, 0, 0, 0, -10, 10, 0, 0, 0, -14, -10], [0, -6, 0, 0, 0, -10, 6, 0, 0, 0, 18, -2], [-5, 0, -13, 9, 18, 0, 0, 0, 0, -2, 0, 0], [0, 16, 0, 0, 0, 2, -1, 0, 9, 0, 8, 9], [0, 9, 0, 0, 0, -1, -22, 0, 4, 0, 27, 4], [-4, 0, 0, -4, 4, 0, 0, 14, 0, 0, 0, 0], [0, 10, 0, 0, 0, 5, 12, 0, 9, 0, 5, 0], [8, 0, 0, 4, -4, 0, 0, 2, 0, 0, 0, 0], [0, 20, 0, 0, 0, 10, -6, 0, 10, 0, 10, 0], [4, 0, 14, -8, -4, 0, 0, 4, 0, 4, 0, 0], [8, 0, -12, 2, 4, 0, 0, 0, 0, -8, 0, 0], [0, -6, 0, 0, 0, -3, -10, 0, -12, 0, -3, 0], [6, 0, 0, 2, -2, 0, 0, 15, 0, 0, 0, 0], [0, 4, 0, 0, 0, 4, -32, 0, 4, 0, 32, 4], [8, 0, 8, -16, -8, 0, 0, 2, 0, 2, 0, 0], [17, 0, -13, -2, -4, 0, 0, 0, 0, 5, 0, 0], [10, 0, 12, -20, -10, 0, 0, -14, 0, -14, 0, 0], [0, 4, 0, 0, 0, 4, 6, 0, 4, 0, -6, 4], [0, 7, 0, 0, 0, 19, -7, 0, 0, 0, 0, -5], [0, -14, 0, 0, 0, -7, 4, 0, -10, 0, -7, 0], [-4, 0, -10, 8, 4, 0, 0, -5, 0, -5, 0, 0], [9, 0, 0, 8, -8, 0, 0, 12, 0, 0, 0, 0], [-5, 0, 15, -5, -10, 0, 0, 0, 0, -2, 0, 0], [0, 12, 0, 0, 0, 4, 26, 0, 8, 0, -22, 8], [0, 2, 0, 0, 0, 8, -2, 0, 0, 0, 12, -4], [0, -16, 0, 0, 0, -6, 22, 0, -11, 0, -27, -11], [0, 0, 0, 0, 0, -1, 0, 0, 0, 0, -38, 1], [-5, 0, -29, 10, 5, 0, 0, -1, 0, -1, 0, 0], [0, -2, 0, 0, 0, -7, 2, 0, 0, 0, -7, 3], [2, 0, -28, -4, -2, 0, 0, -6, 0, -6, 0, 0], [-5, 0, 7, -1, -2, 0, 0, 0, 0, 9, 0, 0], [-18, 0, 0, -9, 9, 0, 0, 2, 0, 0, 0, 0], [0, 5, 0, 0, 0, 15, -13, 0, 10, 0, 8, 10], [10, 0, 0, -1, 1, 0, 0, 1, 0, 0, 0, 0], [-6, 0, 0, 3, 6, 0, 0, 0, 0, 9, 0, 0], [0, -12, 0, 0, 0, 4, 4, 0, -4, 0, -12, -4], [0, -24, 0, 0, 0, -12, -1, 0, -10, 0, -12, 0], [2, 0, 0, -1, 1, 0, 0, -17, 0, 0, 0, 0], [0, -6, 0, 0, 0, -3, 20, 0, -8, 0, -3, 0], [12, 0, -16, 2, 4, 0, 0, 0, 0, 6, 0, 0], [-8, 0, 0, 2, -2, 0, 0, -12, 0, 0, 0, 0], [0, -2, 0, 0, 0, -1, -8, 0, 12, 0, -1, 0], [0, 16, 0, 0, 0, 6, -26, 0, 11, 0, 31, 11], [0, -2, 0, 0, 0, -2, 2, 0, 0, 0, 3, -2], [18, 0, -34, 8, 16, 0, 0, 0, 0, 6, 0, 0], [7, 0, 0, 3, -3, 0, 0, 10, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 16, 0, -10, 0, 0, 0], [0, -15, 0, 0, 0, -19, 15, 0, 0, 0, -39, -11], [0, 20, 0, 0, 0, 20, -10, 0, 20, 0, 10, 20], [0, 8, 0, 0, 0, -4, 19, 0, 2, 0, -13, 2], [18, 0, 0, 5, -5, 0, 0, 9, 0, 0, 0, 0], [5, 0, 24, -10, -5, 0, 0, -10, 0, -10, 0, 0], [0, -2, 0, 0, 0, 1, 2, 0, 0, 0, -18, -5], [0, 4, 0, 0, 0, 2, 10, 0, 13, 0, 2, 0], [-3, 0, 23, 6, 3, 0, 0, -2, 0, -2, 0, 0], [0, -1, 0, 0, 0, 3, 1, 0, 0, 0, 16, -5], [-1, 0, 8, 2, 1, 0, 0, -8, 0, -8, 0, 0], [0, 4, 0, 0, 0, 13, -4, 0, 0, 0, 13, -5], [0, 3, 0, 0, 0, -8, -3, 0, 0, 0, -1, 14], [1, 0, 6, -2, -1, 0, 0, 16, 0, 16, 0, 0], [-22, 0, 14, 4, 8, 0, 0, 0, 0, -10, 0, 0], [0, -24, 0, 0, 0, -12, -4, 0, -6, 0, -12, 0], [0, 6, 0, 0, 0, 3, 2, 0, -10, 0, 3, 0], [-22, 0, 0, 2, -2, 0, 0, 0, 0, 0, 0, 0], [-20, 0, 0, -4, 4, 0, 0, -11, 0, 0, 0, 0], [-4, 0, 0, 2, 4, 0, 0, 0, 0, 6, 0, 0], [-2, 0, 2, 4, 2, 0, 0, 3, 0, 3, 0, 0], [-14, 0, 0, -8, 8, 0, 0, -12, 0, 0, 0, 0], [-30, 0, 22, 4, 8, 0, 0, 0, 0, -10, 0, 0], [0, -8, 0, 0, 0, -4, 8, 0, 6, 0, -4, 0], [35, 0, 0, 3, -3, 0, 0, -1, 0, 0, 0, 0], [0, 16, 0, 0, 0, -8, 12, 0, 4, 0, 0, 4], [0, 2, 0, 0, 0, 1, -25, 0, 0, 0, 1, 0], [31, 0, 0, 5, -5, 0, 0, -2, 0, 0, 0, 0], [0, -11, 0, 0, 0, -14, 11, 0, 0, 0, -8, -8], [7, 0, -33, 13, 26, 0, 0, 0, 0, 12, 0, 0], [0, 0, 0, 0, 0, -4, 32, 0, -2, 0, -30, -2], [0, -4, 0, 0, 0, -8, -17, 0, -6, 0, 19, -6], [-12, 0, -32, 24, 12, 0, 0, 4, 0, 4, 0, 0], [10, 0, 41, -20, -10, 0, 0, -5, 0, -5, 0, 0]];
    aps := ConvertToHeckeField(raw_aps);
    chi := MakeCharacter_546_bk_Hecke(Universe(aps));
    return ExtendMultiplicatively(weight, aps, chi);
end function;


// To make the newform (type ModFrm), type "MakeNewformModFrm_546_2_bk_b();".
// This may take a long time!  To see verbose output, uncomment the SetVerbose lines below.
// The precision argument determines an initial guess on how many Fourier coefficients to use.
// This guess is increased enough to uniquely determine the newform.
function MakeNewformModFrm_546_2_bk_b(:prec:=12)
    chi := MakeCharacter_546_bk();
    f_vec := qexpCoeffs();
    Kf := Universe(f_vec);
    // SetVerbose("ModularForms", true);
    // SetVerbose("ModularSymbols", true);
    S := CuspidalSubspace(ModularForms(chi, 2));
    S := BaseChange(S, Kf);
    maxprec := NextPrime(997) - 1;
    while true do
        trunc_vec := Vector(Kf, [0] cat [f_vec[i]: i in [1..prec]]);
        B := Basis(S, prec + 1);
        S_basismat := Matrix([AbsEltseq(g): g in B]);
        if Rank(S_basismat) eq Min(NumberOfRows(S_basismat), NumberOfColumns(S_basismat)) then
            S_basismat := ChangeRing(S_basismat,Kf);
            f_lincom := Solution(S_basismat,trunc_vec);
            f := &+[f_lincom[i]*Basis(S)[i] : i in [1..#Basis(S)]];
            return f;
        end if;
        error if prec eq maxprec, "Unable to distinguish newform within newspace";
        prec := Min(Ceiling(1.25 * prec), maxprec);
    end while;
end function;


// To make the Hecke irreducible modular symbols subspace (type ModSym)
// containing the newform, type "MakeNewformModSym_546_2_bk_b();".
// This may take a long time!  To see verbose output, uncomment the SetVerbose line below.
// The default sign is -1.  You can change this with the optional parameter "sign".
function MakeNewformModSym_546_2_bk_b( : sign := -1)
    R<x> := PolynomialRing(Rationals());
    chi := MakeCharacter_546_bk();
    // SetVerbose("ModularSymbols", true);
    Snew := NewSubspace(CuspidalSubspace(ModularSymbols(chi,2,sign)));
    Vf := Kernel([<5,R![16, 0, -144, 0, 1248, 0, -424, 0, 108, 0, -12, 0, 1]>],Snew);
    return Vf;
end function;