voxcity.simulator_gpu.solar.radiation
=====================================

.. py:module:: voxcity.simulator_gpu.solar.radiation

.. autoapi-nested-parse::

   Radiation solver for palm-solar.

   Main module that integrates all components to compute
   shortwave (solar) radiation fluxes with multi-bounce reflections
   following PALM's RTM (Radiative Transfer Model) methodology.

   PALM Alignment Notes:
   - Solar position: Uses PALM's calc_zenith formula exactly (solar.py)
   - SVF calculation: Uses PALM's vffrac_up formula with proper weighting (svf.py)
   - Reflection steps: Default nrefsteps=3 matches PALM
   - Extinction coefficient: Default ext_coef=0.6 matches PALM
   - Beer-Lambert law: Same exponential attenuation through canopy
   - Direction indices: IUP=0, IDOWN=1, etc. match PALM convention

   Key differences from PALM:
   - GPU-accelerated via Taichi (PALM uses Fortran+MPI)
   - Real-time view factor computation (PALM pre-computes sparse matrix)
   - Shortwave only (PALM includes longwave radiation)
   - Axis-aligned surfaces only (PALM supports slant surfaces)

   Input convention:
   - sw_direct: Direct Normal Irradiance (DNI) in W/m²
   - sw_diffuse: Diffuse Horizontal Irradiance (DHI) in W/m²



Attributes
----------

.. autoapisummary::

   voxcity.simulator_gpu.solar.radiation.IUP
   voxcity.simulator_gpu.solar.radiation.IDOWN
   voxcity.simulator_gpu.solar.radiation.INORTH
   voxcity.simulator_gpu.solar.radiation.ISOUTH
   voxcity.simulator_gpu.solar.radiation.IEAST
   voxcity.simulator_gpu.solar.radiation.IWEST


Classes
-------

.. toctree::
   :hidden:

   /autoapi/voxcity/simulator_gpu/solar/radiation/RadiationConfig
   /autoapi/voxcity/simulator_gpu/solar/radiation/RadiationModel

.. autoapisummary::

   voxcity.simulator_gpu.solar.radiation.RadiationConfig
   voxcity.simulator_gpu.solar.radiation.RadiationModel


Module Contents
---------------

.. py:data:: IUP
   :value: 0


.. py:data:: IDOWN
   :value: 1


.. py:data:: INORTH
   :value: 2


.. py:data:: ISOUTH
   :value: 3


.. py:data:: IEAST
   :value: 4


.. py:data:: IWEST
   :value: 5