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Breaking changes

Breaking changes#

4.0.0#

heyoka 4 includes several backwards-incompatible changes.

API/behaviour changes#

Changes to make_vars()#

The make_vars() function now returns a single expression (rather than an array of expressions) if a single argument is passed in input. This means that code such as

auto [x] = make_vars("x");

needs to be rewritten like this:

auto x = make_vars("x");

Terminal events callbacks#

The second argument in the signature of callbacks for terminal events, a bool conventionally called mr, has been removed. This flag was meant to signal the possibility of multiple roots in the event function within the cooldown period, but it never worked as intended and it has thus been dropped.

Adapting existing code for this API change is straightforward: you just have to remove the second argument from the signature of a terminal event callback.

Step callbacks and propagate_*()#

The way step callbacks interact with the propagate_*() functions has changed. Specifically:

  • step callbacks are now passed by value into the propagate_*() functions (whereas previously they would be passed by reference), and

  • step callbacks are now part of the return value. Specifically:

    • for the scalar propagate_for() and propagate_until() functions, the step callback is the sixth element of the return tuple, while for the batch variants the step callback is the second element of the return tuple;

    • for the scalar propagate_grid() function, the step callback is the fifth element of the return tuple, while for the batch variant the step callback is the first element of the return tuple.

The ensemble propagation functions have been modified in an analogous way.

Adapting existing code for the new API should be straightforward. In most cases it should be just a matter of:

  • adapting structured bindings declarations to account for the new element in the return tuple of scalar propagations,

  • adjusting the indexing into the return tuple when fetching a specific element,

  • accounting for the fact that batch propagations now return a tuple of two elements rather than a single value.

Changes to propagate_grid()#

The propagate_grid() functions of the adaptive integrators now require the first element of the time grid to be equal to the current integrator time. Previously, in case of a difference between the integrator time and the first grid point, heyoka would propagate the state of the system up to the first grid point with propagate_until().

If you want to recover the previous behaviour, you will have to invoke manually propagate_until(grid[0]) before invoking propagate_grid().

General#

  • heyoka now requires LLVM>=13.

  • heyoka is now a C++20 project.

  • heyoka now requires fmt>=9.

  • heyoka now requires mp++ 1.x.

2.0.0#

  • The minimum supported LLVM version has been bumped from 10 to 11.

1.0.0#

  • The make_nbody_sys() function has been replaced by the model::nbody() function, with identical semantics.

0.16.0#

  • The pairwise_sum() function has been replaced by a new function called sum() with similar semantics. sum() should behave as a drop-in replacement for pairwise_sum().

  • The tuple returned by the propagate_for/until() functions in a scalar integrator has now 5 elements, rather than 4. The new return value at index 4 is the continuous output function object. This change can break code which assumes that the tuple returned by the propagate_for/until() functions has a size of 4, such as:

    auto [r0, r1, r2, r3] = ta.propagate_until(...);

    The fix should be straightforward in most cases, e.g.:

    auto [r0, r1, r2, r3, r4] = ta.propagate_until(...);

    Similarly, the propagate_for/until() functions in a batch integrator, which previously returned nothing, now return the continuous output function object.

0.15.0#

  • The function class now uses reference semantics. This means that copy operations on non-trivial expressions now result in shallow copies, not deep copies (as it was previously the case). This change does not have repercussions on the integrators’ API, but user code manipulating expressions may need to be adapted.

0.10.0#

  • The callback that can (optionally) be passed to the propagate_*() functions must now return a bool indicating whether the integration should continue or not. The callback used to return void.

0.8.0#

  • The direction of a non-terminal event is now specified with the (optional) keyword argument direction for the event’s constructor (whereas before the direction could be specified via an unnamed argument).

  • An int argument has been appended to the signature of the events’ callbacks. This new argument represents the sign of the derivative of the event equation at the event trigger time, and its value will be -1 for negative derivative, 1 for positive derivative and 0 for zero derivative.

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