https://github.com/smirik/mercury
N-body fortran integrator
https://github.com/smirik/mercury
astronomy bulirsch-stoer celestial-mechanics integrator
Last synced: 3 months ago
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N-body fortran integrator
- Host: GitHub
- URL: https://github.com/smirik/mercury
- Owner: smirik
- License: gpl-3.0
- Created: 2012-05-01T11:51:49.000Z (about 14 years ago)
- Default Branch: master
- Last Pushed: 2023-02-18T11:37:05.000Z (over 3 years ago)
- Last Synced: 2023-03-11T06:16:58.850Z (about 3 years ago)
- Topics: astronomy, bulirsch-stoer, celestial-mechanics, integrator
- Language: Fortran
- Homepage:
- Size: 186 KB
- Stars: 49
- Watchers: 22
- Forks: 24
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
The John E Chambers N-Body integrator
-------------------------------------
This software was initially created by John E. Chambers. It is the N-Body integrator based on Bulirsh-Stoer, Everhart and other methods. As-is, it can integrate any star system like our Solar System.
Currently, this Gnu Fortran github project is configured for Linux and Mac OS X users. It is certainly adaptable for Windows and other O/S environments.
### Manual Authored by John E. Chambers
See ```JOHN_E_CHAMBERS.md```
### How to Prepare for use
- Clone the repository from github to local storage somewhere.
- Position (cd) into the ```mercury``` folder.
- ```make build``` # Compile and link edit all programs.
### Try the Sample files
- ```make gen-in``` # Copy the sample files to the ```mercury6``` input files.
- ```mercury6``` # Execute the N-Body integrator.
### Mercury6 Standard Output (displayed) based on the Sample Files
```
Integrating massive bodies and particles up to the same epoch.
Beginning the main integration.
Date: 2119 8 6.4 dE/E: 3.38494E-13 dL/L: -9.19199E-15
Date: 2229 2 15.8 dE/E: 7.94146E-13 dL/L: 7.57420E-14
Date: 2338 8 24.1 dE/E: 9.69144E-13 dL/L: 1.50381E-13
Date: 2448 2 29.8 dE/E: 1.47573E-12 dL/L: 2.74473E-13
Date: 2557 9 11.2 dE/E: 1.43055E-12 dL/L: 2.25571E-13
Date: 2667 3 23.6 dE/E: 9.88369E-13 dL/L: -2.38992E-14
Date: 2776 10 2.8 dE/E: 6.86847E-13 dL/L: -2.16380E-13
Date: 2886 4 10.5 dE/E: 1.19048E-12 dL/L: -2.06268E-13
Date: 2995 10 21.6 dE/E: 1.01778E-12 dL/L: -2.15460E-13
Date: 3105 5 1.7 dE/E: 1.36844E-12 dL/L: -1.03502E-13
Date: 3214 11 7.1 dE/E: 5.73796E-13 dL/L: -4.11434E-13
Date: 3324 5 16.7 dE/E: 6.31800E-13 dL/L: -3.48928E-13
Date: 3433 11 26.4 dE/E: -1.85514E-13 dL/L: -7.66980E-13
Integration complete.
```
### Executables Produced by Make
**mercury6**
This is the basic integration programme. It contains all of the
code to carry out integrations using any of the
algorithms described by John E. Chambers and elsewhere.
Text-format output files (*.dmp, *.tmp)
are not used by the subsequent ```element6``` and ```close6``` programmes. They seem to be historical intermediate files. Note that file X.tmp = file X.dmp. They could use more explanation!
Binary output files ```ce.out``` (used by ```close6```) and ```xv.out``` (used by ```element6```) are produced in a machine-independent compressed format. They could use more explanation!
Text-format output file ```info.out``` contains a summary of the input parameters.
NOTE: Some of the parameters reside in the *.in files (changes probably do not requiring recompilation) and some of the parameters are specified in the Fortran include files - ```mercury.inc``` and ```swift.inc``` (changes require recompilation).
**element6**
This programme converts the mercury6 output file ```xv.out``` into
a set of text-format files (*.aei) that contain Keplerian orbital elements for each of the
objects of the integration. These files allow you to see how the orbit of each object
change with time, thus can be used as the basis for making
graphs or movies using a graphics/video package.
The resultant text-format ```element.out``` file contains a summary of body features.
The sample input files will yield ```element6``` output files for the Solar System planets, Apollo, and Apophis.
**close6**
This programme converts the mercury6 output file ```ce.out```
into a set of text-format files (*.clo) containing details of close encounters between
objects during the integration.
The sample input files will yield ```close6``` output for the Solar System planets, Apollo, and Apophis.
### Makefile Options
```
- make build : Build the Fortran programs
- make unbuild : Remove all Fortran program executables
- make gen-in : Generate input files by copying them from samples
- make rm-gen : Remove all files generated by the Fortran programs
- make rm-in : Remove all input files used by the Fortran programs
- make clean : Remove all input files, generated files, and the executables
```
### Fortran Include Files
#### mercury.inc
This contains constants and general parameters used by programmes in
the mercury package.
CAUTION: Make sure that you understand the implications of changing any of the parameter values.
#### swift.inc
This contains constants and parameters used in the subroutines written
by H.Levison and M.Duncan (1994, Icarus, vol 108, pp18). These
subroutines have names that begin with either `drift' or `orbel'.
CAUTION: Make sure that you understand the implications of changing any of the parameter values.
### Input Data from other Programmes
Please note that if you use other programs to create input data files
you must maintain data items in gfortran double precision format (e.g. use "d" exponent)