# SpacePy Dependencies

SpacePy relies on several other pieces of software for complete functionality. Installing SpacePy links to details on installing the required software for each platform.

Unless otherwise noted, a dependency may be installed after SpacePy, and the new functionality will be available the next time SpacePy is imported.

Currently required versions are documented here. Dependency version support describes future support.

## Hard Dependencies

Without these packages installed, SpacePy will not function.

### Python 2.7+

Python is the core language for SpacePy. Python 3 is strongly recommended and will be required soon. See Python 2 End of Support.

Required to install SpacePy.

### NumPy 1.10+

NumPy provides the high-performance array data structure used throughout SpacePy. Version 1.10 or later is required.

Required to install SpacePy. f2py is part of NumPy, but is sometimes packaged separately; it is required (at installation time) if `irbempy` is to be used.

Due to a numpy bug, numpy 1.15.0 is not supported. Use 1.15.1 or later.

On Python 3.9, numpy 1.18 or later is required.

### dateutil

If you choose not to install matplotlib, dateutil 1.4 or later is required. (Installing matplotlib will fulfill this dependency.)

### C compiler

If you are installing SpacePy from source, a working C compiler is required. (Not necessary for the Windows binary installer.)

## Soft Dependencies

Without these packages, SpacePy will install, but certain features may not be available. Usually an ImportError means a dependency is missing.

These are simply marked as dependencies in SpacePy metadata and thus will be automatically installed when using dependency-resolving methods such as pip.

### SciPy 0.11+

SciPy provides several useful scientific and numerical functions build on top of NumPy. It is highly recommended. The following modules may have limited functionality without SciPy:

> - `coordinates`

> - `ctrans`

> - `empiricals`

> - `seapy`

> - `toolbox`

### matplotlib 1.5.0+

matplotlib is the preferred plotting package for Python. It is highly recommended. Without it, you will not be able to effectively visualize data, and the following modules may have limited functionality or fail entirely:

> - `plot`

> - `poppy`

> - `pybats`

> - `radbelt`

> - `seapy`

> - `toolbox`

### h5py 2.6+

h5py provides a Python interface to HDF5 files. It is required for the HDF import/export capability of `datamodel` and for use of the `omni` module.

### CDF 2.7+

NASA’s CDF library provides access to Common Data Format files. It is required for `pycdf`, and thus for the CDF import/export capability of `datamodel`.

Warning

Unlike the Python-based dependencies, the CDF library must be installed if pycdf support is needed; it will not be automatically installed.

### Fortran compiler

If installing from source, `irbempy` requires a Fortran compiler. (This is not required for the Windows binary installer). Supported compilers are the GNU compiler `gfortran`, the older GNU compiler `g77`, and the Portland Group PGI compiler.

If `irbempy` is to be used, the Fortran compiler (and f2py) must be installed before SpacePy.

`coordinates` requires `irbempy` to use the IRBEM-based backend, but the new CTrans-based backend can be used without Fortran. See the `coordinates` documentation for the `use_irbem` option.

### Astropy 1.0+

`time` requires Astropy if conversion to/from Astropy `Time` is desired.

`coordinates` requires Astropy if conversion to/from Astropy `SkyCoord` is desired.

## Soft Dependency Summary

The following table summarizes, by SpacePy module, the functionality that is lost if a soft dependency is not installed. If there is nothing for a given dependency/module combination, the module is unaffected by that dependency.

SpacePy functionality lost without soft dependencies
| CDF | Fortran compiler | h5py | matplotlib | SciPy | AstroPy
--- | --- | --- | --- | --- | --- | ---
`coordinates` |  | `Coords` IRBEM backend (except Windows binaries) |  |  | `Entire module` | `from_skycoord()` `to_skycoord()`
`ctrans` |  |  |  |  | `Entire module` |
`datamodel` | `toCDF()` `fromCDF()` `toCDF()` |  | `toHDF5()` `fromHDF5()` `toHDF5()` |  |  |
`empiricals` |  |  |  |  | `vampolaPA()` `omniFromDirectionalFlux()` |
`irbempy` |  | `Entire module` (except Windows binaries) |  |  |  |
`LANLstar` |  | May be required to install ffnet. |  |  |  |
`omni` |  |  | `Entire module` |  |  |
`plot` |  |  |  | `Entire module` |  |
`poppy` |  |  |  | `assoc()` `plot()` `plot_mult()` `plot_two_ppro()` |  |
`pybats` |  |  |  | `regrid()` `dgcpm` `interact` `kyoto` `pwom` `ram` `rim` All plotting functions: `add_body()` `add_planet()` `add_pram_bz()` `quicklook()` `add_dst_quicklook()` `add_b_magsphere()` `add_b_magsphere_legacy()` `add_body()` `add_comp_plot()` `add_contour()` `add_cont_shell()` `add_grid_plot()` `add_pcolor()` `add_planet()` `add_plot()` `add_stream_scatter()` `add_ae_quicklook()` `add_contour()` `add_kp_quicklook()` `add_orbit_plot()` `plot_res()` `plotbox()` `plot_res()` `test_asymtote()` `test_dipole()` |  |
`pycdf` | `Entire module` |  |  |  |  |
`radbelt` |  |  |  | `plot()` `plot_obs()` |  |
`seapy` |  |  |  | `Entire module` | `sea_signif()` |
`time` |  |  |  |  |  | AstroPy support in `Ticktock`
`toolbox` |  |  |  | `tCommon()` `linspace()` if using `datetime` inputs `logspace()` if using `datetime` inputs | `dist_to_list()` `intsolve()` `poisson_fit()` |