Camb

* Added [get_lensed_gradient_cls](https://camb.readthedocs.io/en/latest/results.html#camb.results.CAMBdata.get_lensed_gradient_cls) function for flat-sky non-perturbative lensing reconstruction responses
* Fix HMCode bug for w/=-1 models
* Fix k^2 factor in 21cm transfer function output
* Misc minor bug fixes, code and doc tidies

Fix bugs in Fortran Makefile and get_total_cls.

Misc bug fixes, and support for passing BBN interpolation table name as bbn_predictor in [set_cosmology](https://camb.readthedocs.io/en/latest/model.html#camb.model.CAMBparams.set_cosmology).

This is a major new release, with CAMB now configured mainly as a Python package (wrapping modern Fortran for fast numerics). See the [example notebook](https://camb.readthedocs.io/en/latest/CAMBdemo.html) for examples of usage and now comprehensive [documentation](https://camb.readthedocs.io).


Major new features (in Python and Fortran) include:

- Integrated CAMB sources, for CMB, CMB lensing, lensing convergence, number counts and 21cm including all linear velocity and GR effects; [SplinedSourceWindow and GaussianWindow](https://camb.readthedocs.io/en/latest/sources.html) classes for setting SourceWindows array describing additional sources.

- New [set_initial_power_function](https://camb.readthedocs.io/en/latest/model.html#camb.model.CAMBparams.set_initial_power_function) and [set_initial_power_table functions](https://camb.readthedocs.io/en/latest/model.html#camb.model.CAMBparams.set_initial_power_table) to set initial power spectra from arbitrary python function or sampled arrays

- [DarkEnergy](https://camb.readthedocs.io/en/latest/dark_energy.html), [InitialPower](https://camb.readthedocs.io/en/latest/initialpower.html), [NonLinearModel](https://camb.readthedocs.io/en/latest/nonlinear.html), [ReionizationModel](https://camb.readthedocs.io/en/latest/reionization.html) and [RecombinationModel](https://camb.readthedocs.io/en/latest/recombination.html) classes that can be dynamically assigned to [CAMBparams](https://camb.readthedocs.io/en/latest/model.html#camb.model.CAMBparams) object fields.

- Easily switch Dark Energy model between fluid and PPF, and support for setting custom w(z) evolution

- Python command line camb script. Functions to load .ini file settings from python scripts.

Python changes:

- [set_cosmology](https://camb.readthedocs.io/en/latest/model.html#camb.model.CAMBparams.set_cosmology) now supports more general exact thetastar as well as H0 and cosmomc_theta.
- [read_ini](https://camb.readthedocs.io/en/latest/camb.html#camb.read_ini) and [run_ini](https://camb.readthedocs.io/en/latest/camb.html#camb.run_ini) functions
- Reworked python-fortran interface using metaclass and decorators, supporting allocatable arrays and class instances and directly import and call of Fortran class methods
- Support multiple [CAMBdata](https://camb.readthedocs.io/en/latest/results.html#camb.results.CAMBdata) result instances, and results object can be called safely in any order (removing most global variables)
- [CAMBparams](https://camb.readthedocs.io/en/latest/model.html#camb.model.CAMBparams) read-only properties for omegam, N_eff, omegab, omegac, omaganu, h
- T_CMB changes handled consistently
- [set_params](https://camb.readthedocs.io/en/latest/camb.html#camb.set_params) supports options for changing dark energy, initial power and non-linear model classes
- [set_params](https://camb.readthedocs.io/en/latest/camb.html#camb.set_params) can set CAMBparam members if not already used as an argument (and things like InitPower.ns via an input string)
- Fields support named enumerations, name-length fields for arrays, fortran-compatible boolean and help
docs include help for field values (auto-generated via metaclass)
- Faster and array versions of various background functions
- SecondOrderPK non-linear model class available from Python
- Optional support for CosmoRec and HyRec [RecombinationModel](https://camb.readthedocs.io/en/latest/recombination.html) classes (need to compile with them linked)
- Updated BBN model default to Parthenope 2017 as Planck 2018 analysis
- "setup.py make" command to re-build the Fortran library, which also works on Windows if gfortran is installed.

General changes

- Changed [CAMBparams](https://camb.readthedocs.io/en/latest/model.html#camb.model.CAMBparams) parameters to be physical density parameters ombh2, omch3, omnuh2 (+omk)
- Modest speed improvement from using higher order series solutions for background neutrino density combined with linear rather than log spline.
- Uses splined a(t) for perturbation evolution rather than evolving for each perturbation mode; tensor spectrum results now much faster
- More accurate background calculations with partial parallelism
- Finer every-L sampling at L=11-15 (small change in EE). Updated c_l interpolation template.
- min_l and custom source functions now set as parts of [CAMBparams](https://camb.readthedocs.io/en/latest/model.html#camb.model.CAMBparams)
- Account for radiation when setting dark energy density from matter densities and omk
- Smoother default reionization history parameters around helium second reionization
- Use matter temperature evolution from recfast (still harmlessly wrong - as before - from reionization onwards)
- scalarCovCls.dat and _array outputs for lensing potential now deflection angle
- Halofit default updated to HMcode to match Planck 2018 analysis
- Added TAxionEffectiveFluid example specific dark energy class implementation
- high_accuracy_default option removed (is now the default)
- Git repository now uses submodule for [forutils](https://github.com/cmbant/forutils)

Underlying Fortran changes:

- Fortran 2003 Object-oriented code restructuring; Fortran code structure now closer to the python ([see class trees](https://camb.info/doc/classes/_index.html)). [this is a breaking change]
- Now requires [gfortran 6 or ifort 14 or higher](https://camb.readthedocs.io/en/latest/fortran_compilers.html#fortran-compilers) (ifort 18.0.1 or higher recommended)
- Fix for auto-kmax when using lensing from command line

<ul>
<li>Option to use HMCode 2015 version (thanks Alex Mead)</li>
<li><b>accurate_massive_neutrino_transfers</b> option if accurate neutrino transfer functions needed at late time</li>
<li>Output text file precision increased</li>
<li>Warning if accurate_BB=T but other options not set sensibly for accurate lensing BB</li>
<LI><A HREF="https://camb.readthedocs.org/en/latest">Python CAMB wrapper</A>:
<ul>
<li>On linux system now builds with ifort if available (~35% faster)</li>
<li>More efficient and new vector support for <a href="https://camb.readthedocs.io/en/latest/camb.html?highlight=angular_diameter_distance#camb.CAMBdata.angular_diameter_distance">angular_diameter_distance</a>
and related background functions </li>
<li><a href="https://camb.readthedocs.io/en/latest/bbn.html">bbn module</a> generalisation to allow more general table interpolation and vector arguments; added <a href="http://www2.iap.fr/users/pitrou/primat.htm">PRIMAT table</a> (thanks Cyril Pitrou)</li>
<li>Improvements for default settings in various cases</li>
<li><a href="https://camb.readthedocs.io/en/latest/camb.html?highlight=get_background_time_evolution#camb.CAMBdata.get_background_time_evolution">get_background_time_evolution</a> can now get T_b, the baryon temperature</li>
<li><a href="https://camb.readthedocs.io/en/latest/camb.html?highlight=save_cmb_power_spectra#camb.CAMBdata.save_cmb_power_spectra">save_cmb_power_spectra</a> convenience function</li>
<li>Changes for <a href="https://github.com/JesusTorrado/cobaya">Cobaya</a> compatibility (thanks Jesus Torrado)</li>
<li><a href="https://camb.readthedocs.io/en/latest/camb.html?highlight=get_matter_power_interpolator#camb.get_matter_power_interpolator">get_matter_power_interpolator</a>
has extrap_kmap to efficiently get tails by extrapolation</li>
<li><a href="https://camb.readthedocs.io/en/latest/camb.html#camb.CAMBdata.get_matter_power_interpolator">get_matter_power_interpolator</a>
now also available as method of results object for optimization purposes</li>
<li>mathutils module with convenience functions like Wigner 3j, pseudo-CL coupling, and fast Gauss-Legendre and x^T C^{-1} x evaluation</li>
<li>Doc and example notebook improvements/additional examples and warnings</li>
</ul>

- HMCode bug fix and speed up (thanks Alex Mead)
- Refactoring in equations.f90 so all scalar source outputs now computed in derivs function; support for custom source functions (as used by python camb.symbolic module)
- [Python CAMB](https://camb.readthedocs.org/en/latest):
- Added [camb.symbolic](http://camb.readthedocs.io/en/latest/symbolic.html) module using sympy, to get equations, convert between gauges, and produce and compile CAMB code from analytic results in different gauges. See the [demo notebook](http://nbviewer.jupyter.org/github/cmbant/CAMB/blob/master/pycamb/docs/ScalEqs.ipynb) demonstrating how to use this, set custom sources, plot perturbation evolution and calculate angular power spectra of different things.
- Add [camb.emission_angle](http://camb.readthedocs.io/en/latest/emission_angle.html) module to get BB power from emission angle and time delay ([1706.02673](http://arxiv.org/abs/1706.02673))
- Added [camb.postborn](http://camb.readthedocs.io/en/latest/postborn.html) module to get the field rotation power spectrum and associated BB power ([1605.05662](http://arxiv.org/abs/1605.05662))
- Support for BBN-consistency values of Y_He by interpolation from table; new tables from Parthenope supplied (thanks Ofelia Pisanti)
- H_of_z functions now support arrays of redshifts
- Add nonlinear parameter to model.set_matter_power
- AccurateReionization is now switched on by default
- *CMB_outputscale* and *raw_cl* options to python CMB power spectra output functions to get CL or DL, and use different units
- Added get_fsigma8() function
- Python 3.6 compatibility
- "pip install camb" now working cleanly
- Makefile improvements to build pycamb using gfortran even if ifort present (can use "make COMPILER=gfortran" to force gfortran)
- Bug fixes


Jan2017
- Python CAMB wrapper [correlations module](http://camb.readthedocs.io/en/latest/correlations.html):
- Transform between CL and CMB correlation functions
- Lensed power spectra and correlation functions from unlensed spectra and lensing power spectrum (useful for delensing)
- Matrix of derivatives of lensed power spectra with respect to lensing power and unlensed CL
- Added halofit_casarini=7 for PKequal dark energy fitting (thanks Luciano Casarini; [arXiv:0810.0190](http://arxiv.org/abs/0810.0190), [arXiv:1601.07230](http://arxiv.org/abs/1601.07230))
- Fixed compilation issue with gfortran 6.3


Nov2016
- CAMB_SetNeutrinoHierarchy function and python wrapper neutrino_hierarchy option for set_cosmology function (to configure to use two eigenstate approximation to normal or inverted hierarchies)
- Various misc small bug fixes, improvements and compiler compatibility changes


May2016
- Added support for [HMCODE](http://arxiv.org/abs/1505.07833) Halofit version (halofit_version=5; thanks Alex Mead); Takahashi remains the default as before
- [Python CAMB](https://camb.readthedocs.org/en/latest)
- [camb.get_matter_power_interpolator](http://camb.readthedocs.io/en/latest/camb.html#camb.get_matter_power_interpolator) function to get 2D spline object for evaluating P(k,z);
See the [sample notebook](http://camb.readthedocs.io/en/latest/CAMBdemo.html) for an example of how to use this to calculate a lensing spectrum
- Result object functions to get unsplined matter power ([get_linear_matter_power_spectrum](http://camb.readthedocs.io/en/latest/camb.html#camb.CAMBdata.get_linear_matter_power_spectrum),[get_nonlinear_matter_power_spectrum](http://camb.readthedocs.io/en/latest/camb.html#camb.CAMBdata.get_nonlinear_matter_power_spectrum))
- Result object function to get redshift from conformal time (redshift_at_comoving_radial_distance)
- [camb.set_halofit_version](http://camb.readthedocs.io/en/latest/camb.html#camb.set_halofit_version) to set halofit version;
- Option to set cosmomc_theta rather than H_0 (thanks Marius Millea)
- Wigner 3j function for convenience (camb.bispectrum.threej).