kconnour / pydisort

pyDISORT

This project is designed to allow you to compile the latest DISORT code into an importable Python binary file.

Installation

Before installing this project, you must have a FORTRAN compiler installed on your computer. Once you've done that, you can simply install this package from Terminal via: pip install .. Then, you can import the package in Python with: import disort. You can call any of the subroutines used in the DISORT code from the disort package, but you will most likely be primarily calling the main algorithm with: disort.disort(<50+ args>).

During the installation process, numpy's f2py module will compile the DISORT source files into a single interface file. The meson build backend will then compile code into an importable .so file. This will make the installation take slightly longer than a project comprised of bytecode files, but it should be clearer where source code originates in case you want to make modifications to the source code to suit your needs.

Modifications

I made a small number of changes to the DISORT source code, largely to get it compatible with f2py. These are outlined below.

DISORT.f

• (lines 388--395) I added f2py code to inform it what the output variables should be. These are interpreted by fortran as comments so it didn't change anything about how the fortran code works.
• (line 435) I modified RHOU's 1st dimension to be MAXCMU instead of MAXUMU. This allows DISOBRDF.f to make RHOU.

DISOBRDF.f

• (lines 101--105) I added f2py code to inform it what the output variables should be. These are interpreted by fortran as comments so it didn't change anything about how the fortran code works.
• (line 83) I changed REAL BRDF_ARG(4) to REAL BRDF_ARG(6). This allows me to add 6 parameters to custom surface phase functions.

BDREF.f

• (line 60) I changed REAL BRDF_ARG(4) to REAL BRDF_ARG(6). This allows me to add 6 parameters to a surface phase function.
• (lines 71--72) I added a line at the top REAL ASYM, FRAC, ROUGHNESS to accommodate these parameters.
• (lines 157--169) I added ELSEIF (IREF.eq.5) to handle a Hapke HG2 phase function.
• (lines 170--183) I added ELSEIF (IREF.eq.6) to handle a Hapke HG2 + surface roughness phase function.
• (lines 505 onward) I added the 2 Hapke surface phase functions.

pyRT_DISORT

This project is usable (and hopefully helpful) as is. However, it is often beneficial to have helper routines to create a number of the variables needed as inputs to the main DISORT algorithm. pyRT_DISORT is a companion project to create those arrays. Check it out if desired.