commit c3f825a19c9f22ec12fdf220052213455081f67a
parent 572eabf7ade0c9d1927a6eb5c4bc838a276569f9
Author: Vincent Forest <vincent.forest@meso-star.com>
Date: Mon, 22 Feb 2021 12:47:36 +0100
Update the man pages
Rename the htrdr man page in htrdr-atmosphere and slightly change its
content from this renaming. Write the new htrdr man page and update all
remaining ones according to this new infrastructure.
Diffstat:
8 files changed, 534 insertions(+), 447 deletions(-)
diff --git a/cmake/CMakeLists.txt b/cmake/CMakeLists.txt
@@ -32,7 +32,7 @@ set(VERSION ${VERSION_MAJOR}.${VERSION_MINOR}.${VERSION_PATCH})
add_subdirectory(core)
add_subdirectory(atmosphere)
add_subdirectory(commands)
-#add_subdirectory(doc)
+add_subdirectory(doc)
################################################################################
# Define output & install directories
diff --git a/cmake/doc/CMakeLists.txt b/cmake/doc/CMakeLists.txt
@@ -29,7 +29,7 @@ endif()
################################################################################
# Copy doc files
################################################################################
-set(MAN_NAMES htrdr-image.5 htrdr-materials.5 htrdr-obj.5)
+set(MAN_NAMES htrdr.1 htrdr-image.5 htrdr-materials.5 htrdr-obj.5)
set(MAN_FILES)
foreach(_name IN LISTS MAN_NAMES)
@@ -45,9 +45,9 @@ foreach(_name IN LISTS MAN_NAMES)
endforeach()
add_custom_target(man-copy ALL DEPENDS ${MAN_FILES})
-configure_file(${HTRDR_SOURCE_DIR}/../doc/htrdr.1.txt.in
- ${CMAKE_CURRENT_BINARY_DIR}/htrdr.1.txt @ONLY)
-list(APPEND MAN_NAMES htrdr.1)
+configure_file(${HTRDR_SOURCE_DIR}/../doc/htrdr-atmosphere.1.txt.in
+ ${CMAKE_CURRENT_BINARY_DIR}/htrdr-atmosphere.1.txt @ONLY)
+list(APPEND MAN_NAMES htrdr-atmosphere.1)
################################################################################
# ROFF man pages
diff --git a/doc/htrdr-atmosphere.1.txt.in b/doc/htrdr-atmosphere.1.txt.in
@@ -0,0 +1,404 @@
+// Copyright (C) 2018, 2019, 2020, 2021 |Meso|Star> (contact@meso-star.com)
+// Copyright (C) 2018, 2019, 2021 CNRS
+// Copyright (C) 2018, 2019 Université Paul Sabatier
+// (contact-edstar@laplace.univ-tlse.fr)
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <http://www.gnu.org/licenses/>.
+:toc:
+
+htrdr-atmosphere(1)
+===================
+
+NAME
+----
+htrdr-atmosphere - simulate radiative transfert in cloudy atmospheres
+
+SYNOPSIS
+--------
+[verse]
+*htrdr-atmosphere* [_option_]... -a _atmosphere_
+
+DESCRIPTION
+-----------
+*htrdr-atmosphere* simulate radiative transfert in scenes composed of an
+atmospheric gas mixture, clouds, and a ground. It evaluates the intensity
+incoming on each pixel of the sensor array. The underlying algorithm is based
+on a Monte-Carlo method: it consists in simulating a given number of optical
+paths originating from the sensor, directed into the atmosphere, taking into
+account light absorption and scattering phenomena.
+
+Radiative transfert can be evaluated in the visible or the infrared part of the
+spectrum. It uses spectral data that should be provided for the pressure and
+temperature atmospheric vertical profile [1] (*-a* _atmosphere_), the liquid
+water content in suspension within the clouds stored in a *htcp*(5) file (*-c*
+_clouds_), and the optical properties of water droplets that have been obtained
+from a Mie code and formatted according to the *htmie*(5) file format (*-m*
+_mie_). The user also has to set the position of the sun (*-D*
+_azimuth_,_elevation_), the sensor type (*-C* _camera_ or *-p* _rectangle_) and
+its definition (*-i* _image_). It is also possible to provide an *htrdr-obj*(5)
+file representing the ground geometry (*-g* _ground_) whose materials are
+listed in the *htrdr-material*(5) file provided through the *-M* option. Both,
+the clouds and the ground, can be infinitely repeated along the X and Y axis by
+setting the *-r* and the *-R* options, respectively.
+
+Two types of sensor are supported by *htrdr-atmosphere*. The camera (*-C*
+_camera_) is used to render an image of the scene from the given point of view
+while the rectangle sensor (*-p* _rectangle_) is used to compute a flux map.
+
+Spectral dimension can be integrated in many ways (*-s* option). When rendering
+an image (*-C* _camera_), the computation is by default performed for the
+visible part of the spectrum in [380, 780] nanometers, for the three components
+of the CIE 1931 XYZ colorimetric space that are subsequently recombined in
+order to obtain the final color for each pixel, and finally the whole image of
+the scene as seen from the set observation position. The two other ways consist
+in explicitly defining the longwave or shortwave spectral range to handle and
+continuously sampling a wavelength in this range. Actually longwave and
+shortwave are keywords that mean that the source of radiation is whether
+external or internal to the medium, respectively. In shortwave rendering, only
+the pixel radiance is evaluated and stored in the output image. For longwave
+rendering this estimated radiance is then converted to its brightness
+temperature and both are saved in the image. When computing a flux map (*-p*
+_rectangle_), the per pixel flux is saved into the output map whether spectral
+domain is longwave or shortwave.
+
+In *htrdr-atmosphere* the spatial unit 1.0 corresponds to one meter and the
+temperatures are expressed in Kelvin. The estimated radiances are given in
+W/sr/m^2 excepted for monochromatic computations where the computed spectral
+radiance is defined in W/sr/m^2/nm. The fluxes are saved in W/m^2. The results
+are written to the output file if the *-o* option is defined and the standard
+output otherwise. The output image is a list of raw ASCII data formatted with
+respect to the *htrdr-image*(5) file format. Since *htrdr-atmosphere* relies
+on the Monte-Carlo method, each estimation is given with its numerical
+accuracy.
+
+During the simulation, *htrdr-atmosphere* dynamically loads/unloads cloud
+properties to handle clouds whose data that do not feat in main memory.
+*htrdr-atmosphere* also supports shared memory parallelism and relies on the
+Message Passing Interface specification [3] to parallelise its computations in
+a distributed memory environment; it can thus be run either directly or through
+a MPI process launcher like *mpirun*(1).
+
+OPTIONS
+-------
+*-a* _atmosphere_::
+ Path toward the file containing the gas optical properties of the atmosphere.
+ Data must be formatted according to the fileformat described in [1].
+
+*-c* _clouds_::
+ Submit a *htcp*(5) file describing the properties of the clouds. If not
+ defined, only the atmosphere properties submitted through the *-a* option
+ are taken into account.
+
+*-C* <__camera-parameter__:...>::
+ Define the rendering point of view. Available camera parameters are:
+
+ **fov**=**_angle_**;;
+ Vertical field of view of the camera in [30, 120] degrees. By default
+ _angle_ is set to @HTRDR_ARGS_DEFAULT_CAMERA_FOV@ degrees.
+
+ **pos**=**_x_**,**_y_**,**_z_**;;
+ Position of the camera. By default it is set to
+ {@HTRDR_ARGS_DEFAULT_CAMERA_POS@}.
+
+ **tgt**=**_x_**,**_y_**,**_z_**;;
+ Position targeted by the camera. By default it is set to
+ {@HTRDR_ARGS_DEFAULT_CAMERA_TGT@}.
+
+ **up**=**_x_**,**_y_**,**_z_**;;
+ Up vector of the camera. By default it is set to
+ {@HTRDR_ARGS_DEFAULT_CAMERA_UP@}.
+
+*-D* <__azimuth__,__elevation__>::
+ Direction toward the sun center. The direction is defined by two angles in
+ degrees: the __azimuth__ angle in [0, 360[ and the __elevation__ angle in [0,
+ 90]. Following the right-handed convention, the azimuthal rotation is
+ counter-clockwise, with 0 degree on the X axis. The elevation starts from 0
+ degree for a direction in the XY plane, up to 90 degrees at zenith. Thus
+ -D0,0 -D90,0 -D180,0 and -D270,0 will produce solar vectors {+1,0,0} {0,+1,0}
+ {-1,0,0} and {0,-1,0} respectively, while -D__azimuth__,90 will produce
+ {0,0,+1} regardless of _azimuth_ value.
+
+*-d*::
+ Write in _output_ the space partitioning data structures used to speed up
+ the radiative transfer computations in the clouds. The written data are
+ octrees saved in the VTK file format [2]. Each octree node stores the minimum
+ and the maximum of the extinction coefficients of the cloud cells overlapped
+ by the octree node. In the _output_ file, each octree is separated from the
+ previous one by a line with three minus characters, i.e. '---'.
+
+*-f*::
+ Force overwrite of the _output_ file.
+
+*-g* _ground_::
+ Path toward a *htrdr-obj*(5) representing the ground geometry.
+
+*-h*::
+ List short help and exit.
+
+*-i* <__image-parameter__:...>::
+ Define the sensor array. Available image parameters are:
+
+ **def**=**_width_**x**_height_**;;
+ Definition of the image. By default the image definition is
+ @HTRDR_ARGS_DEFAULT_IMG_WIDTH@x@HTRDR_ARGS_DEFAULT_IMG_HEIGHT@.
+
+ **spp**=**_samples-count_**;;
+ Number of samples per pixel estimation. In regular image rendering, a pixel
+ will use "3 * _samples-count_" Monte-Carlo realisations, one set of
+ _samples-count_ realisations for each X, Y and Z component of the CIE 1931
+ XYZ color space. In shortwave/longwave rendering or flux computation, only
+ one set of _samples-count_ is used. By default, *spp* is set to
+ @HTRDR_ARGS_DEFAULT_IMG_SPP@.
+
+*-R*::
+ Infinitely repeat the _ground_ along the X and Y axis.
+
+*-r*::
+ Infinitely repeat the _clouds_ along the X and Y axis.
+
+*-M* _materials_::
+ Path toward a *htrdr-materials*(5) file listing the ground materials.
+
+*-m* _mie_::
+ Path toward a *htmie*(5) file defining the optical properties of water
+ droplets.
+
+*-n* _sky-mtl_::
+ Name of the material representing the sky in the *htrdr-materials*(5) file.
+ By default, _sky-mtl_ is @HTRDR_ARGS_DEFAULT_SKY_MTL_NAME@.
+
+*-O* _cache_::
+ File used to cache the sky data. If the _cache_ file does not exists, it is
+ created and filled with the sky data built from the _clouds_, the
+ _atmosphere_ and the _mie_ input files. This cached data can then be reused
+ in the next runs as long as the input files provided on the command are the
+ same as the ones used to setup the cache; leading to a significant speed-up
+ of the pre-processing step. If _cache_ contains data generated from input
+ files that are not the ones submitted on the command line, an error is
+ notified and the execution is stopped, avoiding the use of wrong cached data.
+ Note that when the cache is used, *htrdr-atmosphere* ignores the arguments
+ used to parametrise the structures partitioning the sky data, i.e. the *-T*
+ and *-V* options.
+
+*-o* _output_::
+ File where *htrdr-atmosphere* writes its _output_ data. If not defined, write
+ results to standard output.
+
+*-p* <__rectangle-parameter__:...>::
+ Switch in flux map computation. The flux is computed for the part of the
+ sensor that is outside any geometry. The rectangular sensor onto which the
+ flux is integrated is defined by the following parameters:
+
+ **pos**=**_x_**,**_y_**,**_z_**;;
+ Position of the center of the rectangle. By default it is set to
+ {@HTRDR_ARGS_DEFAULT_RECTANGLE_POS@}.
+
+ **tgt**=**_x_**,**_y_**,**_z_**;;
+ Position targeted by the rectangle, i.e. *tgt* - *pos* is the rectangle
+ normal. By default it is set to {@HTRDR_ARGS_DEFAULT_RECTANGLE_TGT@}.
+
+ **up**=**_x_**,**_y_**,**_z_**;;
+ Up vector of the rectangle. By default it is set to
+ {@HTRDR_ARGS_DEFAULT_RECTANGLE_UP@}.
+
+ **sz**=**_width_**,**_height_**;;
+ Size of the rectangle. By default it is set to
+ {@HTRDR_ARGS_DEFAULT_RECTANGLE_SZ@}.
+
+*-s* <__spectral-parameter__:...>::
+ Define the type and the range of the spectral integration. Available spectral
+ parameters are:
+
+ **cie_xyz**;;
+ the radiance is computed for the visible part of the spectrum in [380, 780]
+ nanometers with respect to the XYZ CIE 1931 tristimulus values. This is the
+ default comportment of *htrdr-atmosphere*.
+
+ **lw**=*_wlen-min_*,*_wlen-max_*;;
+ perform the spectral sampling continuously in the [_wlen-min_, _wlen-max_]
+ wavelength range (wavelength must be provided in nanometers) according to
+ the Planck function for a reference temperature. If _wlen-min_ and
+ _wlen-max_ are equals the computation is monochromatic. *lw* means for
+ longwave but is here a code word that really means "computation of radiance
+ using the internal source of radiation": in other words, radiation is
+ emitted by the medium and its boundaries (ground and space). Because the
+ application is for the terrestrial atmosphere, internal radiation is
+ emitted in the thermal longwave part of the electromagnetic spectrum.
+ Therefore the default value of the reference temperature used in the
+ spectral sampling is fixed at 290 K.
+
+ **sw**=*_wlen-min_*,*_wlen-max_*;;
+ perform the spectral sampling continuously in the [_wlen-min_, _wlen-max_]
+ wavelength range (wavelength must be provided in nanometers) according to
+ the Planck function for a reference temperature. If _wlen-min_ and
+ _wlen-max_ are equals the computation is monochromatic. In the present
+ case, *sw* means that the source of radiation is external to the medium:
+ because the application is for the terrestrial atmosphere, the value of the
+ reference temperature is by default fixed at 5778 K, i.e. the blackbody
+ temperature of the Sun.
+
+ **Tref**=**_temperature_**;;
+ reference temperature of the Planck function used to continuously sample the
+ longwave/shortwave spectral range. In longwave, it is set to 290 K by
+ default while in shortwave its default value is the blackbody temperature
+ of the sun (i.e. 5778 K).
+
+*-T* _threshold_::
+ Optical thickness used as threshold criteria to partition the properties of
+ the clouds. By default its value is @HTRDR_ARGS_DEFAULT_OPTICAL_THICKNESS_THRESHOLD@.
+ This option is ignored if a cache file is used (option *-O*).
+
+*-t* _threads-count_::
+ Hint on the number of threads to use. By default use as many threads as CPU
+ cores.
+
+*-V* **_x_**,**_y_**,**_z_**::
+ Define the maximum definition of the acceleration data structure that
+ partitions the cloud properties. By default the finest definition is the
+ definition of the submitted *htcp*(5) file. This option is ignored if a cache
+ file is used (option *-O*).
+
+*-v*::
+ Make *htrdr-atmosphere* verbose.
+
+EXAMPLES
+--------
+
+Render a clear sky scene, i.e. a scene without any cloud, whose sun is at
+zenith. The vertical atmospheric gaz mixture along the Z axis is described in
+the *gas.txt* file. the ground geometry is a quad repeated to the infinity
+whose materials are listed in the *material.mtl* file. The camera is positioned
+at *400* meters height and looks toward the positive Y axis. The definition of
+the rendered image is *800* by *600* pixels and the radiance of each pixel
+component is estimated with *64* Monte-Carlo realisations. The resulting image
+is written to *output* excepted if the file already exists; in this case an
+error is notified, the program stops and the *output* file remains unchanged:
+
+ $ htrdr-atmosphere -D0,90 -a gas.txt -m Mie.nc -g quad.obj -R \
+ -M materials.mtl \
+ -C pos=0,0,400:tgt=0,1,0:up=0,0,1 \
+ -i def=800x600:spp=64 \
+ -o output
+
+Add clouds to the previous scene and use a more complex geometry to represent
+the ground. The Mie data are provided through the *Mie.nc* file. The ground
+geometry was carefully designed to be cyclic and can be thus infinitely
+repeated without visual glitches. Use the *-f* option to write the rendered
+image to *output* even though the file already exists. Finally, use the
+*htpp*(1) command to convert the *htrdr-image*(5) saved in output in a regular
+PPM image [4]:
+
+ $ htrdr-atmosphere -D0,90 -a gas.txt -m Mie.nc -g mountains.obj -R \
+ -M materials.mtl \
+ -c clouds.htcp \
+ -C pos=0,0,400:tgt=0,1,0:up=0,0,1 \
+ -i def=800x600:spp=64 \
+ -f -o output
+ $ htpp -o image.ppm output
+
+Render the previous scene in infrared for the wavelengths in [*9200*, *10000*]
+nanometers with a reference temperature of *300* Kelvin:
+
+ $ htrdr-atmosphere -a gas.txt -m Mie.nc -g mountains.obj -R \
+ -M materials.mtl \
+ -c clouds.htcp \
+ -C pos=0,0,400:tgt=0,1,0:up=0,0,1 \
+ -i def=800x600:spp=64 \
+ -s lw=9200,10000:Tref=300
+ -f -o output
+
+Move the sun by setting its azimuthal and elevation angles to *120* and *40*
+degrees respectively. Use the *-O* option to enable the cache mechanism on
+sky data. Increase the image definition to *1280* by *720* and set the
+number of samples per pixel component to *1024*. Write results on standard
+output and convert the resulting image in PPM before visualising it through the
+*feh*(1) image viewer:
+
+ $ htrdr-atmosphere -D120,40 -a gas.txt -m Mie.nc -g mountains.obj -R \
+ -M materials.mtl \
+ -c clouds.htcp \
+ -O my_cache \
+ -C pos=0,0,400:tgt=0,1,0:up=0,0,1 \
+ -i def=1280x720:spp=1024 | htpp | feh -
+
+Compute the downward flux for the shortwave interval [*350*, *4000*] nanometers
+on a square of *100* meters side positionned at the origin at *1* meter height.
+The resolution of the flux map is *500* by *500* pixels and *1000* realisations
+is used to estimate the flux per pixel. It is saved in the *flux_map.txt* file
+even though this file already exists:
+
+ $ htrdr-atmosphere -D0,90 -a gas.txt -m Mie.nc -g plane.obj -R \
+ -M materials.mtl \
+ -c clouds.htcp \
+ -O my_cache \
+ -p pos=0,0,1:tgt=0,0,2:up=0,1,0:sz=100,100 \
+ -i def=500x500:spp=1000 \
+ -s sw=350,4000 \
+ -f -o flux_map.txt
+
+Write into *output* the data structures used to partition the clouds
+properties. Use the *csplit*(1) Unix command to extract from *output* the list
+of the generated grids and save each of them in a specific VTK file whose name
+is *cloud_grid_*<__NUM__>*.vtk with __NUM__ in [0, N-1] where N is the number
+of grids written into *output*:
+
+ $ htrdr-atmosphere -a gas.txt -m Mie.nc -c clouds.htcp -d -f -o output
+ $ csplit -f cloud_grid_ -b %02d.vtk -z --suppress-matched output /^---$/ {*}
+
+Use *mpirun*(1) to launch *htrdr-atmosphere* on several hosts defined in the
+*my_hosts* file. Make the clouds infinite along the X and Y axis:
+
+ $ mpirun --hostfile my_hosts htrdr-atmosphere \
+ -D120,40 -a gas.txt -m Mie.nc -g mountains.obj -R \
+ -M materials.mtl \
+ -c clouds.htcp -r \
+ -C pos=0,0,400:tgt=0,1,0:up=0,0,1 \
+ -i def=1280x720:spp=1024 \
+ -f -o output
+
+NOTES
+-----
+1. High-Tune: Gas Optical Properties file format -
+ <https://www.meso-star.com/projects/high-tune/downloads/gas_opt_prop_en.pdf>
+2. VTK file format -
+ <http://www.vtk.org/wp-content/uploads/2015/04/file-formats.pdf>
+3. MPI specifications - <https://www.mpi-forum.org/docs/>
+4. Portable PixMap - <http://netpbm.sourceforge.net/doc/ppm.html>
+
+COPYRIGHT
+---------
+Copyright $copy; 2018, 2019, 2020, 2021 |Meso|Star> <contact@meso-star.com>.
+Copyright © 2018, 2019, 2021 CNRS
+Copyright © 2018, 2019 Université Paul Sabatier
+<contact-edstar@laplace.univ-tlse.fr>.
+
+LICENSE
+-------
+
+*htrdr-atmosphere* is free software released under the GPLv3+ license: GNU GPL
+version 3 or later <https://gnu.org/licenses/gpl.html>. You are free to change
+and redistribute it. There is NO WARRANTY, to the extent permitted by law.
+
+SEE ALSO
+--------
+*csplit*(1),
+*feh*(1),
+*mpirun*(1),
+*htcp*(5),
+*htmie*(5),
+*htpp*(1),
+*htrdr*(1),
+*htrdr-image*(5),
+*htrdr-materials*(5)
+*htrdr-obj*(5)
diff --git a/doc/htrdr-image.5.txt b/doc/htrdr-image.5.txt
@@ -1,5 +1,7 @@
-// Copyright (C) 2018, 2019, 2020 |Meso|Star> (contact@meso-star.com)
-// Copyright (C) 2018-2019 CNRS, Université Paul Sabatier
+// Copyright (C) 2018, 2019, 2020, 2021 |Meso|Star> (contact@meso-star.com)
+// Copyright (C) 2018, 2019, 2021 CNRS
+// Copyright (C) 2018, 2019 Université Paul Sabatier
+// (contact-edstar@laplace.univ-tlse.fr)
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
@@ -30,37 +32,33 @@ thus ignored as well as empty lines. The first valid line stores 2 unsigned
integers that represent the image definition, i.e. the number of pixels per
line and per column. Then each line stores 8 pixel components.
-If the image is a regular rendering in the visible part of the spectrum (*-C*
-_camera_ and *-s* _cie_xyz_ options in *htrdr*(1)), the pixel components are
-actually 4 pairs of floating points data representing the pixel color encoded
-in the CIE 1931 XYZ color space and the per radiative path computation time.
-The first, second and third pairs encode the estimated integrated radiance in
-W/sr/m^2 of the X, Y and Z pixel components, respectively. The first value of
-each pair is the expected value of the estimated radiance while the second one
-is its associated standard deviation. The fourth pair saves the estimate in
+If the image is a regular rendering in the visible part of the spectrum, the
+pixel components are actually 4 pairs of floating points data representing the
+pixel color encoded in the CIE 1931 XYZ color space and the per radiative path
+computation time. The first, second and third pairs encode the estimated
+integrated radiance in W/sr/m^2 of the X, Y and Z pixel components,
+respectively. The first value of each pair is the expected value of the
+estimated radiance while the second one is its associated standard deviation.
+The fourth pair saves the estimate in microseconds of the per radiative path
+computation time and its standard error.
+
+If the image is an infrared rendering the first and second pixel components
+store the expected value and the standard error, respectively, of the
+estimated brightness temperature in Kelvin. The third and fourth components
+save the expected value and standard deviation of the pixel radiance that is
+either an integrated radiance in W/sr/m^2 or a spectral radiance in
+W/sr/m^2/nm whether this radiance is computed for a spectral range or for one
+wavelength. The fifth and sixth pixel components are unused. Finally the last
+2 pixel components save, as for a regular rendering, the estimate in
microseconds of the per radiative path computation time and its standard
error.
-If the image is an infrared rendering (*-C* _camera_ and *-s*
-*lw*=_wlen-min_,_wlen_max_ options in *htrdr*(1)), the first and second pixel
-components store the expected value and the standard error, respectively, of
-the estimated brightness temperature in Kelvin. The third and fourth
-components save the expected value and standard deviation of the pixel
-radiance that is either an integrated radiance in W/sr/m^2 or a spectral
-radiance in W/sr/m^2/nm whether this radiance is computed for a spectral range
-or for one wavelength. The fifth and sixth pixel components are unused.
-Finally the last 2 pixel components save, as for a regular rendering, the
-estimate in microseconds of the per radiative path computation time and its
-standard error.
-
-If it was generating from a shortwave rendering (*-C* _camera_ and *-s*
-*sw*=_wlen-min_,wlen-max_ options in *htrdr*(1)) the image is formatted as in
+If it was generating from a shortwave rendering the image is formatted as in
longwave rendering mode exepted that the first and second pixel components are
unused since no brightness temperature was evaluated in shortwave.
-For flux computations (*-p* _rectangle_ option in *htrdr*(1)), the first and
-second pixel component stores the expected value and the standard error of the
-pixel flux in W/m^2 for the part of the pixel that is outside any geometry. As
+For flux computations, the first and second pixel component stores the
+expected value and the standard error of the pixel flux in W/m^2. As
previously, the seventh and eighth pixel components store the estimate of the
radiative path computation time in microseconds and its standard error. The
remaining components, i.e. the components 3 to 6, are unused.
diff --git a/doc/htrdr-materials.5.txt b/doc/htrdr-materials.5.txt
@@ -1,5 +1,7 @@
-// Copyright (C) 2018, 2019, 2020 |Meso|Star> (contact@meso-star.com)
-// Copyright (C) 2018-2019 CNRS, Université Paul Sabatier
+// Copyright (C) 2018, 2019, 2020, 2021 |Meso|Star> (contact@meso-star.com)
+// Copyright (C) 2018, 2019, 2021 CNRS
+// Copyright (C) 2018, 2019 Université Paul Sabatier
+// (contact-edstar@laplace.univ-tlse.fr)
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
@@ -20,16 +22,16 @@ htrdr-materials(5)
NAME
----
-htrdr-materials - list of materials used by the ground geometry in htrdr(1)
+htrdr-materials - list of materials used by the geometries in htrdr(1)
DESCRIPTION
-----------
-A *htrdr-materials* file lists the materials that can be used by the ground
-geometry provided through a *htrdr-obj*(5) file to the *htrdr*(1) program.
-Each line of the file gives the name of the material. For opaque materials the
-material name is followed by the path toward the *mrumtl*(5) file storing the
-spectral properties of its associated Bidirectional Reflectance Distribution
-Function. Furthermore, the temperature of the material must be defined too.
+A *htrdr-materials* file lists the materials that can be used by geometries
+provided through a *htrdr-obj*(5) file to the *htrdr*(1) program. Each line
+of the file gives the name of the material. For opaque materials the material
+name is followed by the path toward the *mrumtl*(5) file storing the spectral
+properties of its associated Bidirectional Reflectance Distribution Function.
+Furthermore, the temperature of the material must be defined too.
The material name can be composed of any characters excepted for spaces and
tabulations. The path toward the *mrumtl*(5) file must be a valid path
diff --git a/doc/htrdr-obj.5.txt b/doc/htrdr-obj.5.txt
@@ -1,5 +1,7 @@
-// Copyright (C) 2018, 2019, 2020 |Meso|Star> (contact@meso-star.com)
-// Copyright (C) 2018-2019 CNRS, Université Paul Sabatier
+// Copyright (C) 2018, 2019, 2020, 2021 |Meso|Star> (contact@meso-star.com)
+// Copyright (C) 2018, 2019, 2021 CNRS
+// Copyright (C) 2018, 2019 Université Paul Sabatier
+// (contact-edstar@laplace.univ-tlse.fr)
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
@@ -27,12 +29,14 @@ DESCRIPTION
A *htrdr-obj* file is a regular OBJ [1] composed only of triangular meshes.
Each triangle must be included in a material group as defined by the 'usemtl'
directive. The name of the material group must be of the form
-"<__front-mtl-name__>:<__back-mtl-name__>", where <__front-mtl-name__> and
-<__back-mtl-name__> are strings separated by a colon (:) defining the name of
-the front and back facing materials, respectively. These names can be composed
-of any characters expected for spaces and tabulations. Note that regarding the
-*htrdr*(1) convention, a triangle side is said "front facing" when its
-vertices are clock-wise ordered.
+"<__front-mtl-name__>:[<__interface-mtl-name__>:]<__back-mtl-name__>", where
+<__front-mtl-name__>, <__interface-mtl-name__> and <__back-mtl-name__> are
+strings separated by a colon (:) defining the name of the front, interface,
+and back facing materials, respectively. The interface material name is
+optionnal: it is used for thin geometries, i.e. geometries with no thickness.
+Material names can be composed of any characters expected for spaces and
+tabulations. Note that regarding the *htrdr*(1) convention, a triangle side is
+said "front facing" when its vertices are clock-wise ordered.
Note that to be a valid *htrdr-obj*(5) file for *htrdr*(1), the front and the
back facing names must reference a material listed in *htrdr-materials*(5)
diff --git a/doc/htrdr.1.txt b/doc/htrdr.1.txt
@@ -0,0 +1,77 @@
+// Copyright (C) 2018, 2019, 2020, 2021 |Meso|Star> (contact@meso-star.com)
+// Copyright (C) 2018, 2019, 2021 CNRS
+// Copyright (C) 2018, 2019 Université Paul Sabatier
+// (contact-edstar@laplace.univ-tlse.fr)
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <http://www.gnu.org/licenses/>.
+:toc:
+
+htrdr(1)
+========
+
+NAME
+----
+htrdr - the Monte-Carlo radiative transfert simulator
+
+SYNOPSIS
+--------
+[verse]
+*htrdr* [--version] [--help] <__mode__> [<__args__>]
+
+DESCRIPTION
+-----------
+*htrdr* computes images of scenes composed of semi transparent materials and
+geometries with spectral varying reflectivities. The way the scenes are
+described and the solved Monte-Carlo algorithms are controlled by the _mode_
+argument that defines the computation context.
+
+OPTIONS
+-------
+*--help*::
+ Print short help and exit.
+
+*--version*::
+ Display version information and exit.
+
+MODES
+-----
+
+Each *htrdr* _mode_ is actually a mapping to a seperate command line named
+*htrdr-<__mode__>* with its own set of arguments. Refer to their corresponding
+man page for their complete description.
+
+The available *htrdr-<__mode__>* commands are:
+
+*htrdr-atmosphere*(1)::
+ Radiative transfer computations in a cloudy atmosphere.
+
+*htrdr-combustion*(1)::
+ Radiative transfer computations in a combustion medium.
+
+COPYRIGHT
+---------
+Copyright © 2018, 2019, 2020, 2021 |Meso|Star> <contact@meso-star.com>.
+Copyright © 2018, 2019, 2021 CNRS.
+Copyright © 2018, 2019 Université Paul Sabatier <contact-edstar@laplace.univ-tlse.fr>.
+
+LICENSE
+-------
+*htrdr* is free software released under the GPLv3+ license: GNU GPL version 3
+or later <https://gnu.org/licenses/gpl.html>. You are free to change and
+redistribute it. There is NO WARRANTY, to the extent permitted by law.
+
+SEE ALSO
+--------
+*htrdr-atmosphere*(1),
+*htrdr-combustion*(1)
diff --git a/doc/htrdr.1.txt.in b/doc/htrdr.1.txt.in
@@ -1,398 +0,0 @@
-// Copyright (C) 2018, 2019, 2020 |Meso|Star> (contact@meso-star.com)
-// Copyright (C) 2018-2019 CNRS, Université Paul Sabatier
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with this program. If not, see <http://www.gnu.org/licenses/>.
-:toc:
-
-htrdr(1)
-========
-
-NAME
-----
-htrdr - simulate radiative transfert in cloudy atmospheres
-
-SYNOPSIS
---------
-[verse]
-*htrdr* [_option_]... -a _atmosphere_
-
-DESCRIPTION
------------
-*htrdr* simulate radiative transfert in scenes composed of an atmospheric gas
-mixture, clouds, and a ground. It evaluates the intensity incoming on each
-pixel of the sensor array. The underlying algorithm is based on a Monte-Carlo
-method: it consists in simulating a given number of optical paths originating
-from the sensor, directed into the atmosphere, taking into account light
-absorption and scattering phenomena.
-
-Radiative transfert can be evaluated in the visible or the infrared part of the
-spectrum. It uses spectral data that should be provided for the pressure and
-temperature atmospheric vertical profile [1] (*-a* _atmosphere_), the liquid
-water content in suspension within the clouds stored in a *htcp*(5) file (*-c*
-_clouds_), and the optical properties of water droplets that have been obtained
-from a Mie code and formatted according to the *htmie*(5) file format (*-m*
-_mie_). The user also has to set the position of the sun (*-D*
-_azimuth_,_elevation_), the sensor type (*-C* _camera_ or *-p* _rectangle_) and
-its definition (*-i* _image_). It is also possible to provide an *htrdr-obj*(5)
-file representing the ground geometry (*-g* _ground_) whose materials are
-listed in the *htrdr-material*(5) file provided through the *-M* option. Both,
-the clouds and the ground, can be infinitely repeated along the X and Y axis by
-setting the *-r* and the *-R* options, respectively.
-
-Two types of sensor are supported by *htrdr*. The camera (*-C* _camera_) is
-used to render an image of the scene from the given point of view while the
-rectangle sensor (*-p* _rectangle_) is used to compute a flux map.
-
-Spectral dimension can be integrated in many ways (*-s* option). When rendering
-an image (*-C* _camera_), the computation is by default performed for the
-visible part of the spectrum in [380, 780] nanometers, for the three components
-of the CIE 1931 XYZ colorimetric space that are subsequently recombined in
-order to obtain the final color for each pixel, and finally the whole image of
-the scene as seen from the set observation position. The two other ways consist
-in explicitly defining the longwave or shortwave spectral range to handle and
-continuously sampling a wavelength in this range. Actually longwave and
-shortwave are keywords that mean that the source of radiation is whether
-external or internal to the medium, respectively. In shortwave rendering, only
-the pixel radiance is evaluated and stored in the output image. For longwave
-rendering this estimated radiance is then converted to its brightness
-temperature and both are saved in the image. When computing a flux map (*-p*
-_rectangle_), the per pixel flux is saved into the output map whether spectral
-domain is longwave or shortwave.
-
-In *htrdr* the spatial unit 1.0 corresponds to one meter and the temperatures
-are expressed in Kelvin. The estimated radiances are given in W/sr/m^2 excepted
-for monochromatic computations where the computed spectral radiance is defined
-in W/sr/m^2/nm. The fluxes are saved in W/m^2. The results are written to the
-output file if the *-o* option is defined and the standard output otherwise.
-The output image is a list of raw ASCII data formatted with respect to the
-*htrdr-image*(5) file format. Since *htrdr* relies on the Monte-Carlo method,
-each estimation is given with its numerical accuracy.
-
-During the simulation, *htrdr* dynamically loads/unloads cloud properties to
-handle clouds whose data that do not feat in main memory. *htrdr* also supports
-shared memory parallelism and relies on the Message Passing Interface
-specification [3] to parallelise its computations in a distributed memory
-environment; it can thus be run either directly or through a MPI process
-launcher like *mpirun*(1).
-
-OPTIONS
--------
-*-a* _atmosphere_::
- Path toward the file containing the gas optical properties of the atmosphere.
- Data must be formatted according to the fileformat described in [1].
-
-*-c* _clouds_::
- Submit a *htcp*(5) file describing the properties of the clouds. If not
- defined, only the atmosphere properties submitted through the *-a* option
- are taken into account.
-
-*-C* <__camera-parameter__:...>::
- Define the rendering point of view. Available camera parameters are:
-
- **fov**=**_angle_**;;
- Vertical field of view of the camera in [30, 120] degrees. By default
- _angle_ is set to @HTRDR_ARGS_DEFAULT_CAMERA_FOV@ degrees.
-
- **pos**=**_x_**,**_y_**,**_z_**;;
- Position of the camera. By default it is set to
- {@HTRDR_ARGS_DEFAULT_CAMERA_POS@}.
-
- **tgt**=**_x_**,**_y_**,**_z_**;;
- Position targeted by the camera. By default it is set to
- {@HTRDR_ARGS_DEFAULT_CAMERA_TGT@}.
-
- **up**=**_x_**,**_y_**,**_z_**;;
- Up vector of the camera. By default it is set to
- {@HTRDR_ARGS_DEFAULT_CAMERA_UP@}.
-
-*-D* <__azimuth__,__elevation__>::
- Direction toward the sun center. The direction is defined by two angles in
- degrees: the __azimuth__ angle in [0, 360[ and the __elevation__ angle in [0,
- 90]. Following the right-handed convention, the azimuthal rotation is
- counter-clockwise, with 0 degree on the X axis. The elevation starts from 0
- degree for a direction in the XY plane, up to 90 degrees at zenith. Thus
- -D0,0 -D90,0 -D180,0 and -D270,0 will produce solar vectors {+1,0,0} {0,+1,0}
- {-1,0,0} and {0,-1,0} respectively, while -D__azimuth__,90 will produce
- {0,0,+1} regardless of _azimuth_ value.
-
-*-d*::
- Write in _output_ the space partitioning data structures used to speed up
- the radiative transfer computations in the clouds. The written data are
- octrees saved in the VTK file format [2]. Each octree node stores the minimum
- and the maximum of the extinction coefficients of the cloud cells overlapped
- by the octree node. In the _output_ file, each octree is separated from the
- previous one by a line with three minus characters, i.e. '---'.
-
-*-f*::
- Force overwrite of the _output_ file.
-
-*-g* _ground_::
- Path toward a *htrdr-obj*(5) representing the ground geometry.
-
-*-h*::
- List short help and exit.
-
-*-i* <__image-parameter__:...>::
- Define the sensor array. Available image parameters are:
-
- **def**=**_width_**x**_height_**;;
- Definition of the image. By default the image definition is
- @HTRDR_ARGS_DEFAULT_IMG_WIDTH@x@HTRDR_ARGS_DEFAULT_IMG_HEIGHT@.
-
- **spp**=**_samples-count_**;;
- Number of samples per pixel estimation. In regular image rendering, a pixel
- will use "3 * _samples-count_" Monte-Carlo realisations, one set of
- _samples-count_ realisations for each X, Y and Z component of the CIE 1931
- XYZ color space. In shortwave/longwave rendering or flux computation, only
- one set of _samples-count_ is used. By default, *spp* is set to
- @HTRDR_ARGS_DEFAULT_IMG_SPP@.
-
-*-R*::
- Infinitely repeat the _ground_ along the X and Y axis.
-
-*-r*::
- Infinitely repeat the _clouds_ along the X and Y axis.
-
-*-M* _materials_::
- Path toward a *htrdr-materials*(5) file listing the ground materials.
-
-*-m* _mie_::
- Path toward a *htmie*(5) file defining the optical properties of water
- droplets.
-
-*-n* _sky-mtl_::
- Name of the material representing the sky in the *htrdr-materials*(5) file.
- By default, _sky-mtl_ is @HTRDR_ARGS_DEFAULT_SKY_MTL_NAME@.
-
-*-O* _cache_::
- File used to cache the sky data. If the _cache_ file does not exists, it is
- created and filled with the sky data built from the _clouds_, the
- _atmosphere_ and the _mie_ input files. This cached data can then be reused
- in the next runs as long as the input files provided on the command are the
- same as the ones used to setup the cache; leading to a significant speed-up
- of the pre-processing step. If _cache_ contains data generated from input
- files that are not the ones submitted on the command line, an error is
- notified and the execution is stopped, avoiding the use of wrong cached data.
- Note that when the cache is used, *htrdr* ignores the arguments used to
- parametrise the structures partitioning the sky data, i.e. the *-T* and *-V*
- options.
-
-*-o* _output_::
- File where *htrdr* writes its _output_ data. If not defined, write results to
- standard output.
-
-*-p* <__rectangle-parameter__:...>::
- Switch in flux map computation. The flux is computed for the part of the
- sensor that is outside any geometry. The rectangular sensor onto which the
- flux is integrated is defined by the following parameters:
-
- **pos**=**_x_**,**_y_**,**_z_**;;
- Position of the center of the rectangle. By default it is set to
- {@HTRDR_ARGS_DEFAULT_RECTANGLE_POS@}.
-
- **tgt**=**_x_**,**_y_**,**_z_**;;
- Position targeted by the rectangle, i.e. *tgt* - *pos* is the rectangle
- normal. By default it is set to {@HTRDR_ARGS_DEFAULT_RECTANGLE_TGT@}.
-
- **up**=**_x_**,**_y_**,**_z_**;;
- Up vector of the rectangle. By default it is set to
- {@HTRDR_ARGS_DEFAULT_RECTANGLE_UP@}.
-
- **sz**=**_width_**,**_height_**;;
- Size of the rectangle. By default it is set to
- {@HTRDR_ARGS_DEFAULT_RECTANGLE_SZ@}.
-
-*-s* <__spectral-parameter__:...>::
- Define the type and the range of the spectral integration. Available spectral
- parameters are:
-
- **cie_xyz**;;
- the radiance is computed for the visible part of the spectrum in [380, 780]
- nanometers with respect to the XYZ CIE 1931 tristimulus values. This is the
- default comportment of *htrdr*.
-
- **lw**=*_wlen-min_*,*_wlen-max_*;;
- perform the spectral sampling continuously in the [_wlen-min_, _wlen-max_]
- wavelength range (wavelength must be provided in nanometers) according to
- the Planck function for a reference temperature. If _wlen-min_ and
- _wlen-max_ are equals the computation is monochromatic. *lw* means for
- longwave but is here a code word that really means "computation of radiance
- using the internal source of radiation": in other words, radiation is
- emitted by the medium and its boundaries (ground and space). Because the
- application is for the terrestrial atmosphere, internal radiation is
- emitted in the thermal longwave part of the electromagnetic spectrum.
- Therefore the default value of the reference temperature used in the
- spectral sampling is fixed at 290 K.
-
- **sw**=*_wlen-min_*,*_wlen-max_*;;
- perform the spectral sampling continuously in the [_wlen-min_, _wlen-max_]
- wavelength range (wavelength must be provided in nanometers) according to
- the Planck function for a reference temperature. If _wlen-min_ and
- _wlen-max_ are equals the computation is monochromatic. In the present
- case, *sw* means that the source of radiation is external to the medium:
- because the application is for the terrestrial atmosphere, the value of the
- reference temperature is by default fixed at 5778 K, i.e. the blackbody
- temperature of the Sun.
-
- **Tref**=**_temperature_**;;
- reference temperature of the Planck function used to continuously sample the
- longwave/shortwave spectral range. In longwave, it is set to 290 K by
- default while in shortwave its default value is the blackbody temperature
- of the sun (i.e. 5778 K).
-
-*-T* _threshold_::
- Optical thickness used as threshold criteria to partition the properties of
- the clouds. By default its value is @HTRDR_ARGS_DEFAULT_OPTICAL_THICKNESS_THRESHOLD@.
- This option is ignored if a cache file is used (option *-O*).
-
-*-t* _threads-count_::
- Hint on the number of threads to use. By default use as many threads as CPU
- cores.
-
-*-V* **_x_**,**_y_**,**_z_**::
- Define the maximum definition of the acceleration data structure that
- partitions the cloud properties. By default the finest definition is the
- definition of the submitted *htcp*(5) file. This option is ignored if a cache
- file is used (option *-O*).
-
-*-v*::
- Make *htrdr* verbose.
-
-*--version*::
- Display version information and exit.
-
-EXAMPLES
---------
-
-Render a clear sky scene, i.e. a scene without any cloud, whose sun is at
-zenith. The vertical atmospheric gaz mixture along the Z axis is described in
-the *gas.txt* file. the ground geometry is a quad repeated to the infinity
-whose materials are listed in the *material.mtl* file. The camera is positioned
-at *400* meters height and looks toward the positive Y axis. The definition of
-the rendered image is *800* by *600* pixels and the radiance of each pixel
-component is estimated with *64* Monte-Carlo realisations. The resulting image
-is written to *output* excepted if the file already exists; in this case an
-error is notified, the program stops and the *output* file remains unchanged:
-
- $ htrdr -D0,90 -a gas.txt -m Mie.nc -g quad.obj -R \
- -M materials.mtl \
- -C pos=0,0,400:tgt=0,1,0:up=0,0,1 \
- -i def=800x600:spp=64 \
- -o output
-
-Add clouds to the previous scene and use a more complex geometry to represent
-the ground. The Mie data are provided through the *Mie.nc* file. The ground
-geometry was carefully designed to be cyclic and can be thus infinitely
-repeated without visual glitches. Use the *-f* option to write the rendered
-image to *output* even though the file already exists. Finally, use the
-*htpp*(1) command to convert the *htrdr-image*(5) saved in output in a regular
-PPM image [4]:
-
- $ htrdr -D0,90 -a gas.txt -m Mie.nc -g mountains.obj -R \
- -M materials.mtl \
- -c clouds.htcp \
- -C pos=0,0,400:tgt=0,1,0:up=0,0,1 \
- -i def=800x600:spp=64 \
- -f -o output
- $ htpp -o image.ppm output
-
-Render the previous scene in infrared for the wavelengths in [*9200*, *10000*]
-nanometers with a reference temperature of *300* Kelvin:
-
- $ htrdr -a gas.txt -m Mie.nc -g mountains.obj -R \
- -M materials.mtl \
- -c clouds.htcp \
- -C pos=0,0,400:tgt=0,1,0:up=0,0,1 \
- -i def=800x600:spp=64 \
- -s lw=9200,10000:Tref=300
- -f -o output
-
-Move the sun by setting its azimuthal and elevation angles to *120* and *40*
-degrees respectively. Use the *-O* option to enable the cache mechanism on
-sky data. Increase the image definition to *1280* by *720* and set the
-number of samples per pixel component to *1024*. Write results on standard
-output and convert the resulting image in PPM before visualising it through the
-*feh*(1) image viewer:
-
- $ htrdr -D120,40 -a gas.txt -m Mie.nc -g mountains.obj -R \
- -M materials.mtl \
- -c clouds.htcp \
- -O my_cache \
- -C pos=0,0,400:tgt=0,1,0:up=0,0,1 \
- -i def=1280x720:spp=1024 | htpp | feh -
-
-Compute the downward flux for the shortwave interval [*350*, *4000*] nanometers
-on a square of *100* meters side positionned at the origin at *1* meter height.
-The resolution of the flux map is *500* by *500* pixels and *1000* realisations
-is used to estimate the flux per pixel. It is saved in the *flux_map.txt* file
-even though this file already exists:
-
- $ htrdr -D0,90 -a gas.txt -m Mie.nc -g plane.obj -R \
- -M materials.mtl \
- -c clouds.htcp \
- -O my_cache \
- -p pos=0,0,1:tgt=0,0,2:up=0,1,0:sz=100,100 \
- -i def=500x500:spp=1000 \
- -s sw=350,4000 \
- -f -o flux_map.txt
-
-Write into *output* the data structures used to partition the clouds
-properties. Use the *csplit*(1) Unix command to extract from *output* the list
-of the generated grids and save each of them in a specific VTK file whose name
-is *cloud_grid_*<__NUM__>*.vtk with __NUM__ in [0, N-1] where N is the number
-of grids written into *output*:
-
- $ htrdr -a gas.txt -m Mie.nc -c clouds.htcp -d -f -o output
- $ csplit -f cloud_grid_ -b %02d.vtk -z --suppress-matched output /^---$/ {*}
-
-Use *mpirun*(1) to launch *htrdr* on several hosts defined in the *my_hosts*
-file. Make the clouds infinite along the X and Y axis:
-
- $ mpirun --hostfile my_hosts htrdr \
- -D120,40 -a gas.txt -m Mie.nc -g mountains.obj -R \
- -M materials.mtl \
- -c clouds.htcp -r \
- -C pos=0,0,400:tgt=0,1,0:up=0,0,1 \
- -i def=1280x720:spp=1024 \
- -f -o output
-
-NOTES
------
-1. High-Tune: Gas Optical Properties file format -
- <https://www.meso-star.com/projects/high-tune/downloads/gas_opt_prop_en.pdf>
-2. VTK file format -
- <http://www.vtk.org/wp-content/uploads/2015/04/file-formats.pdf>
-3. MPI specifications - <https://www.mpi-forum.org/docs/>
-4. Portable PixMap - <http://netpbm.sourceforge.net/doc/ppm.html>
-
-COPYRIGHT
----------
-Copyright © 2018, 2019, 2020 |Meso|Star> <contact@meso-star.com>.
-Copyright © 2018, 2019 CNRS, Université Paul Sabatier
-<contact-edstar@laplace.univ-tlse.fr>. *htrdr* is free software released under
-the GPLv3+ license: GNU GPL version 3 or later
-<https://gnu.org/licenses/gpl.html>. You are free to change and redistribute
-it. There is NO WARRANTY, to the extent permitted by law.
-
-SEE ALSO
---------
-*csplit*(1),
-*feh*(1),
-*mpirun*(1),
-*htcp*(5),
-*htmie*(5),
-*htpp*(1),
-*htrdr-image*(5),
-*htrdr-materials*(5)
-*htrdr-obj*(5)
