Iminuit

- Reverted: create MnHesse C++ instance on the stack instead on the heap
- Added least-squares cost function and tests

v1.4.3-test1


v1.4.3-test0

**Bug-fixes**
- Fixed a bug where running `.hesse()` after `.migrad()` would ignore any changes to parameters (fixing/releasing them, changing their values, ...)
- Fix number formatting issues in recently updated quantities display
- Removed engineering suffixes again in favour of standard exponential notation

**Deprecated**
- keyword `forced_parameters` in `Minuit.__init__` is deprecated, use `name`

**Features**
- Added general purpose cost functions for binned and unbinned maximum-likelihood estimation (normal and so called extended)

**Documentation**
- Updated error computation tutorial
- New tutorial which demonstrates usage of cost functions

Hot-fix release to correct an error in `Minuit.merrors` indexing.

Mostly a bug-fix release, but also deprecates more old interface.

**Bug-fixes**

- Fixed a bug when displaying nans in rich displays

**Deprecated**

- `Minuit.minoserror_struct`: use `Minuit.merrors`, which is now an alias for the former
- `Minuit.merrors` now accepts indices and parameter names, like `Minuit.values`, etc.

**Features**

- Show engineering suffixes (1.23k, 123.4M, 0.8G, ...) in rich diplays instead of "scientific format", e.g. 1.23e-3
- New initial step heuristic, replaces pedantic warning about missing step sizes
- New initial value heuristic for parameters with limits

**Documentation**

- New tutorial about using Numba to parallelize and jit-compile cost functions

This release drops Python 2 support and modernizes the interface of iminuit's Minuit object to make it more pythonic. Outdated methods were deprecated and replaced with properties. Keywords in methods were made more consistent. The deprecated interface has been removed from the documentation, but is still there. Old code should still work (if not please file a bug report!).

**Bug-fixes**

- Fixed an exception in the rich display when results were NaN
- `Minuit.migrad_ok()` (now replaced by `Minuit.accurate`) now returns false if HESSE failed after MIGRAD and made the minimum invalid
- Running `Minuit.hesse()` now properly updates the function minimum
- Fixed incorrect `hess_inv` returned by `iminuit.minimize`
- Fixed duplicated printing of pedantic warning messages

**Deprecated**

- `Minuit.list_of_fixed_params()`, `Minuit.list_of_vary_params()`: use `Minuit.fixed`
- `Minuit.migrad_ok()`: use `Minuit.valid`
- `Minuit.matrix_accurate()`: use `Minuit.accurate`
- `Minuit.get_fmin()`: use `Minuit.fmin`
- `Minuit.get_param_states()`: use `Minuit.params`
- `Minuit.get_initial_param_states()`: use `Minuit.init_params`
- `Minuit.get_num_call_fcn()`: use `Minuit.ncalls_total`
- `Minuit.get_num_call_grad()`: use `Minuit.ngrads_total`
- `Minuit.print_param_states()`: use `print()` on `Minuit.params`
- `Minuit.print_initial_param_states()`: use `print()` on `Minuit.init_params`
- `Minuit.hesse(maxcall=...)` keyword: use `ncall=...` like in `Minuit.migrad()`
- `Minuit.edm`: use `Minuit.fmin.edm`

**New features**

- iminuit now uses the PDG formatting rule for quantities with errors
- slicing and basic broadcasting support for `Minuit.values`, `Minuit.errors`, `Minuit.fixed`, e.g. the following works: `m.fixed[:] = True`, `m.values[:2] = [1, 2]`
- `Minuit.migrad(ncall=0)` (the default) now uses MINUITs internal heuristic instead of a flat limit of 10000 calls
- `iminuit.minimize` now supports the `tol` parameter
- `Minuit` now supports `print_level=3`, which shows debug level information when MIGRAD runs
- Binder support and Binder badge for tutorial notebooks added by matthewfeickert

**Documentation**

- New tutorials on error computation and on using automatic differentiation