Category Archives: LMFDB

A bookmarklet to inject colorblind friendly CSS into Travis CI

In my previous post, I noted that the ability to see in color gave me an apparent superpower in quickly analyzing Travis CI and pytest logs.

I wondered: how hard is it to use colorblind friendly colors here?

I had in the back of my mind the thought of the next time I sit down and pair program with someone who is colorblind (which will definitely happen). Pair programming is largely about sharing experiences and ideas, and color disambiguation shouldn’t be a wedge.

I decided that loading customized CSS is the way to go. There are different ways to do this, but an easy method for quick replicability is to create a bookmarklet that adds CSS into the page. So, I did that.

You can get that bookmarklet here. (Due to very sensible security reasons, WordPress doesn’t want to allow me to provide a link which is actually a javascript function. So I make it available on a static, handwritten page).1

Here’s how it works. A Travis log looks typically like this:

After clicking on the bookmarklet, it looks like

This is not beautiful, but it works and it’s very noticable. Nonetheless, when the goal is just to be able to quickly recognize if errors are occuring, or to recognize exceptional lines on a quick scroll-by, the black-text-on-white-box wins the standout crown.

The LMFDB uses pytest, which conveniently produces error summaries at the end of the test. (We used to use nosetest, and we hadn’t set it up to have nice summaries before transitioning to pytest). This bookmark will also effect the error summary, so that it now looks like

Again, I would say this is not beautiful, but definitely noticeable.

As an aside, I also looked through the variety of colorschemes that I have collected over the years. And it turns out that 100 percent of them are unkind to colorblind users, with the exception of the monotone or monochromatic schemes (which are equal in the Harrison Bergeron sense).

We should do better.

Posted in LMFDB, Programming | Tagged , , , , | Leave a comment

Seeing color shouldn’t feel like a superpower

In the last month, I have found myself pair programming with three different people. All three times involved working on the LMFDB. I rarely pair program outside a mentor-mentee or instructor-student situation.1

This is fun. It’s fun seeing other people’s workflows. (In these cases, it happened to be that the other person was usually the one at the keyboard and typing, and I was backseat driving). I live in the terminal, subscribe to the Unix-is-my-IDE general philosophy: vim is my text editor; a mixture of makefiles, linters, and fifos with tmux perform automated building, testing, and linting; git for source control; and a medium-sized but consistently growing set of homegrown bash/python/c tools and scripts make it fun and work how I want.

I’m distinctly interested in seeing tools other people have made for their own workflows. Those scripts that aren’t polished, but get the work done. There is a whole world of git-hooks and aliases that amaze me.

But my recent encounters with pair programming exposed me to a totally different and unexpected experience: two of my programming partners were color blind.2

At first, I didn’t think much of it. I had thought that you might set some colorblind-friendly colorschemes, and otherwise configure your way around it. But as is so often the case with accessibility problems, I underestimated both the number of challenges and the difficulty in solving them (lousy but true aside: most companies almost completely ignore problems with accessibility).

I first noticed differences while trying to fix bugs and review bugfixes in the LMFDB. We use Travis CI for automated testing, and we were examining a build that had failed. We brought up the Travic CI interface and scroll through the log. I immediately point out the failure, since I see something like this.3

an image from Travic CI showing "FAIL" in red and "PASS" in green.
How do you know something failed? asks John, my partner for the day. Oh, it’s because the output is colored, isn’t it? I didn’t know. With the help of the color-blindness simulator, I now see that John saw something like
an image from Travic CI that has been altered to appear with contrast as a red-green colorblind person might see it. Now "FAIL" and "PASS" appear in essentially the same shade.
With red-green colorblindness, there is essentially no difference in the shades of PASSED and FAILED. That’s sort of annoying.

We’d make a few changes, and then rerun some tests. Now we were running tests in a terminal, and the testlogs are scolling by. We’re chatting about emacs wizardy (or c++ magic, or compiler differences between gcc and clang, or something), and I point out that we can stop the tests since three tests have already failed.

He stared at me a bit dumbfoundedly. It was like I had superpowers. I could recognize failures without paying almost any attention, since flashes of red stand out.

But if you don’t recognize differences in color, how would you even know that the terminal outputs different colors for PASSED and FAILED? (We use pytest, which does). A quick look for different colorschemes led to frustration, as there are different sorts of colorblindness and no single solution that will work for everyone (and changing colorschemes is sort of annoying anyway).4

I should say that the Travis team has made some accessibility improvements for colorblind users in the past. The build-passing and build-failing icons used to be little circles that were red or green, as shown here.

That means the build status was effectively invisible to colorblind users. After an issue was raised and discussed, they moved to the current green-checkmark-circle for passing and red-exed-circle for failing, which is a big improvement.

The colorscheme used for Travic CI’s online logs is based on the nord color palette, and there is no colorscheme-switching option. It’s a beautiful and well-researched theme for me, but not for everybody.

The colors on the page are controllable by CSS, but not in a uniform way that works on many sites. (Or at least, not to my knowledge. I would be interested if someone else knew more about this and knew a generic approach. The people I was pair-programming with didn’t have a good solution to this problem).

Should you really need to write your own solution to every colorblind accessibility problem?

In the next post, I’ll give a (lousy but functional) bookmarklet that injects CSS into the page to see Travis CI FAILs immediately.

Posted in LMFDB, Programming | Tagged , , , , | Leave a comment

Sage Days 87 Demo: Interfacing between sage and the LMFDB

Interfacing sage and the LMFDB — a prototype

The lmfdb and sagemath are both great things, but they don’t currently talk to each other. Much of the lmfdb calls sage, but the lmfdb also includes vast amounts of data on $L$-functions and modular forms (hence the name) that is not accessible from within sage.
This is an example prototype of an interface to the lmfdb from sage. Keep in mind that this is a prototype and every aspect can change. But we hope to show what may be possible in the future. If you have requests, comments, or questions, please request/comment/ask either now, or at my email:

Note that this notebook is available on or, and the code is available at

Let’s dive into an example.

In [1]:
# These names will change
from sage.all import *
import LMFDB2sage.elliptic_curves as lmfdb_ecurve
In [2]:
[Elliptic Curve defined by y^2 + x*y = x^3 - 887688*x - 321987008 over Rational Field,
 Elliptic Curve defined by y^2 + x*y + y = x^3 - x^2 + 10795*x - 97828 over Rational Field,
 Elliptic Curve defined by y^2 + x*y + y = x^3 - x^2 - 2294115305*x - 42292668425178 over Rational Field,
 Elliptic Curve defined by y^2 + x*y + y = x^3 - x^2 - 3170*x - 49318 over Rational Field,
 Elliptic Curve defined by y^2 + y = x^3 + 1050*x - 26469 over Rational Field,
 Elliptic Curve defined by y^2 + x*y = x^3 - x^2 - 1240542*x - 531472509 over Rational Field,
 Elliptic Curve defined by y^2 + y = x^3 - x^2 + 8100*x - 263219 over Rational Field,
 Elliptic Curve defined by y^2 + x*y = x^3 + 637*x - 68783 over Rational Field,
 Elliptic Curve defined by y^2 + y = x^3 + x^2 + 36*x - 380 over Rational Field,
 Elliptic Curve defined by y^2 + y = x^3 + x^2 - 2535*x - 49982 over Rational Field]
This returns 10 elliptic curves of rank 1. But these are a bit different than sage’s elliptic curves.

In [3]:
Es =
E = Es[0]
<class 'LMFDB2sage.ell_lmfdb.EllipticCurve_rational_field_lmfdb_with_category'>
Note that the class of an elliptic curve is an lmfdb ElliptcCurve. But don’t worry, this is a subclass of a normal elliptic curve. So we can call the normal things one might call on an elliptic curve.


In [4]:
# Try autocompleting the following. It has all the things!
['CPS_height_bound', 'CartesianProduct',
'Chow_form', 'Hom',
'Jacobian', 'Jacobian_matrix',
'Lambda', 'Np',
'S_integral_points', '_AlgebraicScheme__A',
'_AlgebraicScheme__divisor_group', '_AlgebraicScheme_subscheme__polys',
'_EllipticCurve_generic__ainvs', '_EllipticCurve_generic__b_invariants',
'_EllipticCurve_generic__base_ring', '_EllipticCurve_generic__discriminant',
'_EllipticCurve_generic__is_over_RationalField', '_EllipticCurve_generic__multiple_x_denominator',
'_EllipticCurve_generic__multiple_x_numerator', '_EllipticCurve_rational_field__conductor_pari',
'_EllipticCurve_rational_field__generalized_congruence_number', '_EllipticCurve_rational_field__generalized_modular_degree',
'_EllipticCurve_rational_field__gens', '_EllipticCurve_rational_field__modular_degree',
'_EllipticCurve_rational_field__np', '_EllipticCurve_rational_field__rank',
'_EllipticCurve_rational_field__regulator', '_EllipticCurve_rational_field__torsion_order',
'_Hom_', '__add__', '__cached_methods', '__call__',
'__class__', '__cmp__', '__contains__', '__delattr__',
'__dict__', '__dir__', '__div__', '__doc__',
'__eq__', '__format__', '__ge__', '__getattribute__',
'__getitem__', '__getstate__', '__gt__', '__hash__',
'__init__', '__le__', '__lt__', '__make_element_class__',
'__module__', '__mul__', '__ne__', '__new__',
'__nonzero__', '__pari__', '__pow__', '__pyx_vtable__',
'__rdiv__', '__reduce__', '__reduce_ex__', '__repr__',
'__rmul__', '__setattr__', '__setstate__', '__sizeof__',
'__str__', '__subclasshook__', '__temporarily_change_names', '__truediv__',
'__weakref__', '_abstract_element_class', '_adjust_heegner_index', '_an_element_',
'_ascii_art_', '_assign_names', '_axiom_', '_axiom_init_',
'_base', '_base_ring', '_base_scheme', '_best_affine_patch',
'_cache__point_homset', '_cache_an_element', '_cache_key', '_check_satisfies_equations',
'_cmp_', '_coerce_map_from_', '_coerce_map_via', '_coercions_used',
'_compute_gens', '_convert_map_from_', '_convert_method_name', '_defining_names',
'_defining_params_', '_doccls', '_element_constructor', '_element_constructor_',
'_element_constructor_from_element_class', '_element_init_pass_parent', '_factory_data', '_first_ngens',
'_forward_image', '_fricas_', '_fricas_init_', '_gap_',
'_gap_init_', '_generalized_congmod_numbers', '_generic_coerce_map', '_generic_convert_map',
'_get_action_', '_get_local_data', '_giac_', '_giac_init_',
'_gp_', '_gp_init_', '_heegner_best_tau', '_heegner_forms_list',
'_heegner_index_in_EK', '_homset', '_init_category_', '_initial_action_list',
'_initial_coerce_list', '_initial_convert_list', '_interface_', '_interface_init_',
'_interface_is_cached_', '_internal_coerce_map_from', '_internal_convert_map_from', '_introspect_coerce',
'_is_category_initialized', '_is_valid_homomorphism_', '_isoclass', '_json',
'_kash_', '_kash_init_', '_known_points', '_latex_',
'_lmfdb_label', '_lmfdb_regulator', '_macaulay2_', '_macaulay2_init_',
'_magma_init_', '_maple_', '_maple_init_', '_mathematica_',
'_mathematica_init_', '_maxima_', '_maxima_init_', '_maxima_lib_',
'_maxima_lib_init_', '_modsym', '_modular_symbol_normalize', '_morphism',
'_multiple_of_degree_of_isogeny_to_optimal_curve', '_multiple_x_denominator', '_multiple_x_numerator', '_names',
'_normalize_padic_lseries', '_octave_', '_octave_init_', '_p_primary_torsion_basis',
'_pari_', '_pari_init_', '_point', '_point_homset',
'_polymake_', '_polymake_init_', '_populate_coercion_lists_', '_r_init_',
'_reduce_model', '_reduce_point', '_reduction', '_refine_category_',
'_repr_', '_repr_option', '_repr_type', '_sage_',
'_scale_by_units', '_set_conductor', '_set_cremona_label', '_set_element_constructor',
'_set_gens', '_set_modular_degree', '_set_rank', '_set_torsion_order',
'_shortest_paths', '_singular_', '_singular_init_', '_symbolic_',
'_test_an_element', '_test_cardinality', '_test_category', '_test_elements',
'_test_elements_eq_reflexive', '_test_elements_eq_symmetric', '_test_elements_eq_transitive', '_test_elements_neq',
'_test_eq', '_test_new', '_test_not_implemented_methods', '_test_pickling',
'_test_some_elements', '_tester', '_torsion_bound', '_unicode_art_',
'_unset_category', '_unset_coercions_used', '_unset_embedding', 'a1',
'a2', 'a3', 'a4', 'a6',
'a_invariants', 'abelian_variety', 'affine_patch', 'ainvs',
'algebra', 'ambient_space', 'an', 'an_element',
'analytic_rank', 'analytic_rank_upper_bound', 'anlist', 'antilogarithm',
'ap', 'aplist', 'arithmetic_genus', 'automorphisms',
'b2', 'b4', 'b6', 'b8',
'b_invariants', 'base', 'base_extend', 'base_field',
'base_morphism', 'base_ring', 'base_scheme', 'c4',
'c6', 'c_invariants', 'cartesian_product', 'categories',
'category', 'change_ring', 'change_weierstrass_model', 'cm_discriminant',
'codimension', 'coerce', 'coerce_embedding', 'coerce_map_from',
'complement', 'conductor', 'congruence_number', 'construction',
'convert_map_from', 'coordinate_ring', 'count_points', 'cremona_label',
'database_attributes', 'database_curve', 'db', 'defining_ideal',
'defining_polynomial', 'defining_polynomials', 'degree', 'descend_to',
'dimension', 'dimension_absolute', 'dimension_relative', 'discriminant',
'division_field', 'division_polynomial', 'division_polynomial_0', 'divisor',
'divisor_group', 'divisor_of_function', 'dual', 'dump',
'dumps', 'element_class', 'elliptic_exponential', 'embedding_center',
'embedding_morphism', 'eval_modular_form', 'excellent_position', 'formal',
'formal_group', 'fundamental_group', 'galois_representation', 'gen',
'gens', 'gens_certain', 'gens_dict', 'gens_dict_recursive',
'genus', 'geometric_genus', 'get_action', 'global_integral_model',
'global_minimal_model', 'global_minimality_class', 'has_additive_reduction', 'has_bad_reduction',
'has_base', 'has_cm', 'has_coerce_map_from', 'has_global_minimal_model',
'has_good_reduction', 'has_good_reduction_outside_S', 'has_multiplicative_reduction', 'has_nonsplit_multiplicative_reduction',
'has_rational_cm', 'has_split_multiplicative_reduction', 'hasse_invariant', 'heegner_discriminants',
'heegner_discriminants_list', 'heegner_index', 'heegner_index_bound', 'heegner_point',
'heegner_point_height', 'heegner_sha_an', 'height', 'height_function',
'height_pairing_matrix', 'hom', 'hyperelliptic_polynomials', 'identity_morphism',
'inject_variables', 'integral_model', 'integral_points', 'integral_short_weierstrass_model',
'integral_weierstrass_model', 'integral_x_coords_in_interval', 'intersection', 'intersection_multiplicity',
'intersection_points', 'intersects_at', 'irreducible_components', 'is_atomic_repr',
'is_coercion_cached', 'is_complete_intersection', 'is_conversion_cached', 'is_exact',
'is_global_integral_model', 'is_global_minimal_model', 'is_good', 'is_integral',
'is_irreducible', 'is_isogenous', 'is_isomorphic', 'is_local_integral_model',
'is_minimal', 'is_on_curve', 'is_ordinary', 'is_ordinary_singularity',
'is_p_integral', 'is_p_minimal', 'is_parent_of', 'is_projective',
'is_quadratic_twist', 'is_quartic_twist', 'is_semistable', 'is_sextic_twist',
'is_singular', 'is_smooth', 'is_supersingular', 'is_transverse',
'is_x_coord', 'isogenies_prime_degree', 'isogeny', 'isogeny_class',
'isogeny_codomain', 'isogeny_degree', 'isogeny_graph', 'isomorphism_to',
'isomorphisms', 'j_invariant', 'kodaira_symbol', 'kodaira_type',
'kodaira_type_old', 'kolyvagin_point', 'label', 'latex_name',
'latex_variable_names', 'lift_x', 'lll_reduce', 'lmfdb_page',
'local_coordinates', 'local_data', 'local_integral_model', 'local_minimal_model',
'lseries', 'lseries_gross_zagier', 'manin_constant', 'matrix_of_frobenius',
'minimal_discriminant_ideal', 'minimal_model', 'minimal_quadratic_twist', 'mod5family',
'modular_degree', 'modular_form', 'modular_parametrization', 'modular_symbol',
'modular_symbol_numerical', 'modular_symbol_space', 'multiplication_by_m', 'multiplication_by_m_isogeny',
'multiplicity', 'mwrank', 'mwrank_curve', 'neighborhood',
'newform', 'ngens', 'non_minimal_primes', 'nth_iterate',
'objgen', 'objgens', 'optimal_curve', 'orbit',
'ordinary_model', 'ordinary_primes', 'padic_E2', 'padic_height',
'padic_height_pairing_matrix', 'padic_height_via_multiply', 'padic_lseries', 'padic_regulator',
'padic_sigma', 'padic_sigma_truncated', 'parent', 'pari_curve',
'pari_mincurve', 'period_lattice', 'plane_projection', 'plot',
'point', 'point_homset', 'point_search', 'point_set',
'pollack_stevens_modular_symbol', 'preimage', 'projection', 'prove_BSD',
'q_eigenform', 'q_expansion', 'quadratic_transform', 'quadratic_twist',
'quartic_twist', 'rank', 'rank_bound', 'rank_bounds',
'rational_parameterization', 'rational_points', 'real_components', 'reduce',
'reduction', 'register_action', 'register_coercion', 'register_conversion',
'register_embedding', 'regulator', 'regulator_of_points', 'rename',
'reset_name', 'root_number', 'rst_transform', 'satisfies_heegner_hypothesis',
'saturation', 'save', 'scale_curve', 'selmer_rank',
'sextic_twist', 'sha', 'short_weierstrass_model', 'silverman_height_bound',
'simon_two_descent', 'singular_points', 'singular_subscheme', 'some_elements',
'specialization', 'structure_morphism', 'supersingular_primes', 'tamagawa_exponent',
'tamagawa_number', 'tamagawa_number_old', 'tamagawa_numbers', 'tamagawa_product',
'tamagawa_product_bsd', 'tangents', 'tate_curve', 'three_selmer_rank',
'torsion_order', 'torsion_points', 'torsion_polynomial', 'torsion_subgroup',
'two_descent', 'two_descent_simon', 'two_division_polynomial', 'two_torsion_rank',
'union', 'variable_name', 'variable_names', 'weierstrass_p',
'weil_restriction', 'zeta_series']
All the things
This gives quick access to some data that is not stored within the LMFDB, but which is relatively quickly computable. For example,

In [5]:
Ideal (-x^3 + x*y*z + y^2*z + 887688*x*z^2 + 321987008*z^3) of Multivariate Polynomial Ring in x, y, z over Rational Field
But one of the great powers is that there are some things which are computed and stored in the LMFDB, and not in sage. We can now immediately give many examples of rank 3 elliptic curves with:

In [6]:
Es =, torsion_order=2)
print("There are {} curves returned.".format(len(Es)))
E = Es[0]
There are 10 curves returned.
Elliptic Curve defined by y^2 + x*y + y = x^3 - 3476*x - 79152 over Rational Field
And for these curves, the lmfdb contains data on its rank, generators, regulator, and so on.

In [7]:
[(-34 : 17 : 1)]
In [8]:
res = []
%time for E in Es: res.append(E.gens()); res.append(E.rank()); res.append(E.regulator())
CPU times: user 971 ms, sys: 6.82 ms, total: 978 ms
Wall time: 978 ms
That’s pretty fast, and this is because all of this was pulled from the LMFDB when the curves were returned by the search() function.
In this case, elliptic curves over the rationals are only an okay example, as they’re really well studied and sage can compute much of the data very quickly. On the other hand, through the LMFDB there are millions of examples and corresponding data at one’s fingertips.

This is where we’re really looking for input.

Think of what you might want to have easy access to through an interface from sage to the LMFDB, and tell us. We’re actively seeking comments, suggestions, and requests. Elliptic curves over the rationals are a prototype, and the LMFDB has lots of (much more challenging to compute) data. There is data on the LMFDB that is simply not accessible from within sage.
email:, or post an issue on

Now let’s describe what’s going on under the hood a little bit

There is an API for the LMFDB at This API is a bit green, and we will change certain aspects of it to behave better in the future. A call to the API looks like

The result is a large mess of data, which can be exported as json and parsed.
But that’s hard, and the resulting data are not sage objects. They are just strings or ints, and these require time and thought to parse.
So we created a module in sage that writes the API call and parses the output back into sage objects. The 22 curves given by the above API call are the same 22 curves returned by this call:

In [9]:
Es =, conductor=11050, max_items=25)
E = Es[0]
The total functionality of this search function is visible from its current documentation.

In [10]:
# Execute this cell for the documentation
    Search the LMFDB for an elliptic curve.

    Note that all inputs are optional, but at least one input is necessary.


    -  ``label=l`` -- a string ``l`` representing a label in the LMFDB.

    -  ``degree=d`` -- an int ``d`` giving the minimum degree of a
       parameterization of the modular curve

    -  ``conductor=c`` -- an int ``c`` giving the conductor of the curve

    -  ``min_conductor=mc`` -- an int ``mc`` giving a lower bound on the
       conductor for desired curves

    -  ``max_conductor=mc`` -- an int ``mc`` giving an upper bound on the
       conductor for desired curves

    -  ``torsion_order=t`` -- an int ``t`` giving the order of the torsion
       subgroup of the curve

    -  ``rank=r`` -- an int ``r`` giving the rank of the curve

    -  ``regulator=f`` -- a float ``f`` giving the regulator of the curve

    -  ``max_items=m`` -- an int ``m`` (default: 10, max: 100) indicating the
       maximum number of results to return

    -  ``base_item=b`` -- an int ``b`` (default: 0) specifying where to start
       returning values from. The search will begin by returning the ``b``th
       curve. Combined with ``max_items`` to return data in chunks.

    -  ``sort=s`` -- a string ``s`` specifying what database field to sort the
       results on. See the LMFDB api for more info.


        sage: Es = search(conductor=11050, rank=2)
        [Elliptic Curve defined by y^2 + x*y = x^3 - x^2 - 442*x + 1716 over Rational Field, Elliptic Curve defined by y^2 + x*y = x^3 - x^2 + 1558*x + 11716 over Rational Field]
        sage: E = E[0]
        sage: E.conductor()
In [11]:
# So, for instance, one could perform the following search, finding a unique elliptic curve, torsion_order=3, degree=4608)
[Elliptic Curve defined by y^2 + y = x^3 + x^2 - 5155*x + 140756 over Rational Field]

What if there are no curves?

If there are no curves satisfying the search criteria, then a message is displayed and that’s that. These searches may take a couple of seconds to complete.
For example, no elliptic curve in the database has rank 5.

In [12]:
No fields were found satisfying input criteria.

How does one step through the data?

Right now, at most 100 curves are returned in a single API call. This is the limit even from directly querying the API. But one can pass in the argument base_item (the name will probably change… to skip? or perhaps to offset?) to start returning at the base_itemth element.

In [13]:
from pprint import pprint
pprint(, max_items=3))              # The last item in this list
pprint(, max_items=3, base_item=2)) # should be the first item in this list
[Elliptic Curve defined by y^2 + x*y = x^3 - 887688*x - 321987008 over Rational Field,
 Elliptic Curve defined by y^2 + x*y + y = x^3 - x^2 + 10795*x - 97828 over Rational Field,
 Elliptic Curve defined by y^2 + x*y + y = x^3 - x^2 - 2294115305*x - 42292668425178 over Rational Field]

[Elliptic Curve defined by y^2 + x*y + y = x^3 - x^2 - 2294115305*x - 42292668425178 over Rational Field,
 Elliptic Curve defined by y^2 + x*y + y = x^3 - x^2 - 3170*x - 49318 over Rational Field,
 Elliptic Curve defined by y^2 + y = x^3 + 1050*x - 26469 over Rational Field]
Included in the documentation is also a bit of hopefulness. Right now, the LMFDB API does not actually accept max_conductor or min_conductor (or arguments of that type). But it will sometime. (This introduces a few extra difficulties on the server side, and so it will take some extra time to decide how to do this).

In [14]:, min_conductor=500, max_conductor=10000)  # Not implemented
NotImplementedError                       Traceback (most recent call last)
<ipython-input-14-3d98f2cf7a13> in <module>()
----> 1, min_conductor=Integer(500), max_conductor=Integer(10000))  # Not implemented

/home/djlowry/Dropbox/EllipticCurve_LMFDB/LMFDB2sage/ in search(**kwargs)
     76             kwargs[item]
     77             raise NotImplementedError("This would be a great thing to have, " +
---> 78                 "but the LMFDB api does not yet provide this functionality.")
     79         except KeyError:
     80             pass

NotImplementedError: This would be a great thing to have, but the LMFDB api does not yet provide this functionality.
Our EllipticCurve_rational_field_lmfdb class constructs a sage elliptic curve from the json and overrides (somem of the) the default methods in sage if there is quicker data available on the LMFDB. In principle, this new object is just a sage object with some slightly different methods.
Generically, documentation and introspection on objects from this class should work. Much of sage’s documentation carries through directly.

In [15]:
        Return generators for the Mordell-Weil group E(Q) *modulo*

        .. warning::

           If the program fails to give a provably correct result, it
           prints a warning message, but does not raise an
           exception. Use :meth:`~gens_certain` to find out if this
           warning message was printed.


        - ``proof`` -- bool or None (default None), see
          ``proof.elliptic_curve`` or ``sage.structure.proof``

        - ``verbose`` - (default: None), if specified changes the
           verbosity of mwrank computations

        - ``rank1_search`` - (default: 10), if the curve has analytic
          rank 1, try to find a generator by a direct search up to
          this logarithmic height.  If this fails, the usual mwrank
          procedure is called.

        - algorithm -- one of the following:

          - ``'mwrank_shell'`` (default) -- call mwrank shell command

          - ``'mwrank_lib'`` -- call mwrank C library

        - ``only_use_mwrank`` -- bool (default True) if False, first
          attempts to use more naive, natively implemented methods

        - ``use_database`` -- bool (default True) if True, attempts to
          find curve and gens in the (optional) database

        - ``descent_second_limit`` -- (default: 12) used in 2-descent

        - ``sat_bound`` -- (default: 1000) bound on primes used in
          saturation.  If the computed bound on the index of the
          points found by two-descent in the Mordell-Weil group is
          greater than this, a warning message will be displayed.


        - ``generators`` - list of generators for the Mordell-Weil
           group modulo torsion

        IMPLEMENTATION: Uses Cremona's mwrank C library.


            sage: E = EllipticCurve('389a')
            sage: E.gens()                 # random output
            [(-1 : 1 : 1), (0 : 0 : 1)]

        A non-integral example::

            sage: E = EllipticCurve([-3/8,-2/3])
            sage: E.gens() # random (up to sign)
            [(10/9 : 29/54 : 1)]

        A non-minimal example::

            sage: E = EllipticCurve('389a1')
            sage: E1 = E.change_weierstrass_model([1/20,0,0,0]); E1
            Elliptic Curve defined by y^2 + 8000*y = x^3 + 400*x^2 - 320000*x over Rational Field
            sage: E1.gens() # random (if database not used)
            [(-400 : 8000 : 1), (0 : -8000 : 1)]
Modified methods should have a note indicating that the data comes from the LMFDB, and then give sage’s documentation. This is not yet implemented. (So if you examine the current version, you can see some incomplete docstrings like regulator().)

In [16]:
        Return the regulator of the curve. This is taken from the lmfdb if available.

            In later implementations, this docstring will probably include the
            docstring from sage's regular implementation. But that's not
            currently the case.

This concludes our demo of an interface between sage and the LMFDB.

Thank you, and if you have any questions, comments, or concerns, please find me/email me/raise an issue on LMFDB’s github.
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