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Before starting to use the code, be sure that you have the following compilers and python libraries in your machine
- gfortran (or your favorite fortran compiler)
- OpenMP
- numpy
- matplotlib
- seaborn (optional)
We tested this code using Linux, including Fedora and Ubuntu. This code has also been being built on MAC computers.
Just clone or download pyaneti.
git clone https://github.com/oscaribv/pyaneti
The advantage about cloning the repository is the possibility to follow the changes to this package easily with git pull (learn more about git at https://git-scm.com/).
The next step is to enter the pyaneti folder and see what we can find inside it
cd pyaneti
ls
LICENSE src inpy makefile pyaneti.py README.md
Now compile the code typing make (you can also compile the code in parallel following these steps)
make
If you have all the dependencies installed, the making process should end without error.
You know pyaneti has compiled if there is a *.so file created in your main pyaneti directory (example pyaneti.cpython-36m-x86_64-linux-gnu.so or pyaneti.so)
If you have problems compiling the code, check this.
Now you are ready to run the code for the first time, just type
./pyaneti.py test
or
python pyaneti.py test
The program will start. You will see something like:
==============================
------------------------------
INITIAL CONFIGURATION
------------------------------
Star = test
No. planets = 1
------------------------------
iter max = 100000000
thin factor = 1
nconv = 500
nwalkers = 100
------------------------------
fit RV = [True]
fit Transit = [True]
------------------------------
LC data = free
cadence time = 30.000 min
n rebinning = 1
Stellar priors = [True]
------------------------------
PLANET testb
------------------------------
PRIOR RANGES
------------------------------
T0 = u[ 2448285.0500 , 2448285.1500 ]
P = u[ 365.2060 , 365.3060 ]
ew1= f[ 0.0000 , 1.0000 ]
ew2= f[ 0.0000 , 1.0000 ]
b = f[ 0.0000 , 1.0000 ]
a = g[ 200.0000 , 250.0000 ]
rp = u[ 0.0000 , 0.1000 ]
K = u[ 0.0000 , 0.0010 ]
------------------------------
Other parameter priors
------------------------------
q1 = g[ 0.3464 , 0.0500 ]
q2 = g[ 0.2839 , 0.0500 ]
Super_telescope = u[ 21.0719 , 23.0721 ]
==============================
CREATING RANDOM SEED
CREATING CHAINS
STARTING MCMC CALCULATION
RV datapoints = 36
TR datapoints = 112
No. parameters = 8
dof = 140
==================================
Chain statistics
==================================
chain | reduced chi^2
best : 64667.93
worst : **********
mean : **********
==================================
STARTING INFINITE LOOP!
==================================
Chain statistics
==================================
chain | reduced chi^2
best : 0.95
worst : 1.05
mean : 0.99
==================================
==================================
PERFOMING GELMAN-RUBIN
TEST FOR CONVERGENCE
==================================
==================================
CHAINS HAVE NOT CONVERGED YET!
500 ITERATIONS MORE!
==================================
==================================
Chain statistics
==================================
chain | reduced chi^2
best : 0.95
worst : 1.09
mean : 0.99
==================================
==================================
PERFOMING GELMAN-RUBIN
TEST FOR CONVERGENCE
==================================
==================================
CHAINS HAVE CONVERGED
==================================
CREATING OUTPUT DATA FILES
==================================
STARTING CHAIN CLUSTERING
Initial number of chains: 100
Final number of chains: 100
--------------------------------------------------------------
Summary:
N_chains = 100
N_iter = 500
thin_factor = 1
N_rv_data = 36
N_tr_data = 112
N_data = 148
N_pars = 8
chi2_rv = 7.2765
chi2_tr = 125.9964
chi2 = 133.2729
dof = 140
chi2/dof = 0.9519
ln likelihood_rv = 377.7453
ln likelihood_tr = 1131.1755
ln likelihood = 1508.9208
BIC = -2977.8640
AIC = -3001.8417
--------------------------------------------------------------
INPUT STELLAR PARAMETERS
--------------------------------------------------------------
M_* = 1.0000000 - 0.1000000 + 0.1000000 solar masses
R_* = 1.0000000 - 0.1000000 + 0.1000000 solar radii
T_* = 5772.0000000 - 100.0000000 + 100.0000000 K
--------------------------------------------------------------
Parameters test b
-------------------------Fitted-------------------------------
T0 = 2448285.0955436 - 0.0031192 + 0.0031409 days
P = 365.2508520 - 0.0049167 + 0.0048356 days
ew 1 = 0.0000000 - 0.0000000 + 0.0000000
ew 2 = 0.0000000 - 0.0000000 + 0.0000000
b = 0.0000000 - 0.0000000 + 0.0000000
a/R* = 215.4640517 - 2.3708930 + 2.5122541
rp/R* = 0.0093235 - 0.0000712 + 0.0000775
K = 0.0881821 - 0.0024223 + 0.0023856 m/s
-------------------------Derived------------------------------
Mp = 0.9841032 - 0.0704355 + 0.0718640 M_earth
Rp = 1.0173252 - 0.1028264 + 0.1013333 R_earth
e = 0.0000000 - 0.0000000 + 0.0000000
w = 0.0000000 - 0.0000000 + 0.0000000 deg
i = 90.0000000 - 0.0000000 + 0.0000000 deg
a = 1.0019439 - 0.1014392 + 0.1005043 AU
Insolation = 0.9967687 - 0.0707513 + 0.0741733 F_Earth
rho* = 1.4183711 - 0.0463035 + 0.0502306 g/cm^3 (transit)
rho* = 1.4065628 - 0.3676615 + 0.5586840 g/cm^3 (stellar paramters)
rho_p = 5.1298925 - 1.3074050 + 1.9887038 g/cm^3
g_p = 936.8970215 - 30.5861395 + 32.3670771 cm/s^2 (K and Rp/R*)
g_p = 933.8572371 - 172.6787114 + 234.1233896 cm/s^2 (planet parameters)
Tperi = 2448193.7827742 - 0.0039813 + 0.0041039 days
Teq = 278.1026529 - 5.0720559 + 5.0352570 K (albedo=0)
T_tot = 13.0713846 - 0.1507021 + 0.1448215 hours
T_full = 12.8294707 - 0.1483685 + 0.1432300 hours
--------------------------------------------------------------
-------------------- Other parameters -----------------------
q1 = 0.3760168 - 0.0418577 + 0.0442539
q2 = 0.3157777 - 0.0460379 + 0.0468480
u1 = 0.3855446 - 0.0574350 + 0.0598140
u2 = 0.2246861 - 0.0583548 + 0.0612362
Sys. vel. Super_telescope = 22.0719865 - 0.0000015 + 0.0000016 m/s
--------------------------------------------------------------
Creating outpy/test_out/test_posterior.pdf
Creating outpy/test_out/test_correlations.pdf
Creating outpy/test_out/testb_tr.pdf
Creating outpy/test_out/test_rv_all.pdf
Creating outpy/test_out/testb_rv.pdf
If you see this output it means that pyaneti ended succesfully.
Now let us check the plots (I use evince but you can use your favourite pdf reader)
evince outpy/test_out/testb_tr.pdf outpy/test_out/testb_rv.pdf
You will see some nice plots that look like this
Let me explain you briefly what this test fit was about:
If you were an advanced alien civilization with really high technology, and "lucky" enough to see an Earth-like planet crossing in front of a Sun-like star, this is how the Earth would look like to you.
Look at those well-known parameters:
- 1 Earth Mass
- 1 Earth radii
- Period of 365 days
- 1 AU semi-major axis
- Density of ~5.5 g/cm^2,
- Gravity of ~10 m/s^2.
Of course, you would need a spectrograph with a precision of a few cm/s and also a very nice photometer, and an excellent way to remove stellar intrinsic signals in your data, but that is another story.
If you are at this point, you learned two things. First, with good data you can obtain really nice planet parameters and second, you learned how to run pyaneti.
