```eval_rst
.. _th_parameter_info:
```
# Looking up the parameters of a theory

The parameters for all of the theories can be found in the `theory.db` file.
The `theory.db` file is installed together as part of the validphys package.
This is an sqlite database file. The information contained within this file can also be
viewed [within the docs](theory-indexes).

The tools required to extract the parameters for a given theory are already in
the validphys framework:

```python
>>> from validphys.loader import Loader

>>> l = Loader()
>>> # replace 53 with the relevant theoryID
>>> info_dict = l.check_theoryinfo(53)
>>> print(info_dict)
{'ID': 53, 'PTO': 2, 'FNS': 'FONLL-C', 'DAMP': 0, 'IC': 1, 'ModEv': 'TRN',
'XIR': 1.0, 'XIF': 1.0, 'NfFF': 5, 'MaxNfAs': 5, 'MaxNfPdf': 5, 'Q0': 1.65,
'alphas': 0.118, 'Qref': 91.2, 'QED': 0, 'alphaqed': 0.007496252,
'Qedref': 1.777, 'SxRes': 0, 'SxOrd': 'LL', 'HQ': 'POLE', 'mc': 1.51,
'Qmc': 1.51, 'kcThr': 1.0, 'mb': 4.92, 'Qmb': 4.92, 'kbThr': 1.0, 'mt': 172.5,
'Qmt': 172.5, 'ktThr': 1.0, 'CKM': '0.97428 0.22530 0.003470 0.22520 0.97345 0.041000 0.00862 0.04030 0.999152',
'MZ': 91.1876, 'MW': 80.398, 'GF': 1.1663787e-05, 'SIN2TW': 0.23126, 'TMC': 1,
'MP': 0.938, 'Comments': 'NNPDF3.1 NNLO central', 'global_nx': 0, 'EScaleVar': 1}
```

printing a dictionary in a python terminal is a bit cumbersome, the above
method for checking theory parameters has been added to a command line
script `vp-checktheory` which essentially does the same thing but prints the
table in a nicer format.

The usage is simple:

```
$ vp-checktheory 53
                                          Info for theory 53
ID                                                        53
PTO                                                        2
FNS                                                  FONLL-C
DAMP                                                       0
IC                                                         1
ModEv                                                    TRN
XIR                                                        1
XIF                                                        1
NfFF                                                       5
MaxNfAs                                                    5
MaxNfPdf                                                   5
Q0                                                      1.65
alphas                                                 0.118
Qref      Qref                                                    91.2
QED                                                        0
alphaqed                                          0.00749625
Qedref                                                 1.777
SxRes                                                      0
SxOrd                                                     LL
HQ                                                      POLE
mc                                                      1.51
Qmc                                                     1.51
kcThr                                                      1
mb                                                      4.92
Qmb                                                     4.92
kbThr                                                      1
mt                                                     172.5
Qmt                                                    172.5
ktThr                                                      1
CKM        0.97428 0.22530 0.003470 0.22520 0.97345 0.041...
MZ                                                   91.1876
MW                                                    80.398
GF                                               1.16638e-05
SIN2TW                                               0.23126
TMC                                                        1
MP                                                     0.938
Comments                               NNPDF3.1 NNLO central
global_nx                                                  0
EScaleVar                                                  1
```

Some of the entries of the table have been truncated to fit in the terminal, for
example the CKM matrix elements. If you want to see the
full output or wish to keep a permanent copy of the table then you can use the
command line option `-d`, which stands for `--dumptable` which will save the
table in your current working directory:

```
$ vp-checktheory 53 -d
[INFO]: Saving info table to theory_53_info.csv
                                          Info for theory 53
ID                                                        53
PTO                                                        2
FNS                                                  FONLL-C
DAMP                                                       0
IC                                                         1
ModEv                                                    TRN
XIR                                                        1
XIF                                                        1
NfFF                                                       5
MaxNfAs                                                    5
MaxNfPdf                                                   5
Q0                                                      1.65
alphas                                                 0.118
Qref                                                    91.2
QED                                                        0
alphaqed                                          0.00749625
Qedref                                                 1.777
SxRes                                                      0
SxOrd                                                     LL
HQ                                                      POLE
mc                                                      1.51
Qmc                                                     1.51
kcThr                                                      1
mb                                                      4.92
Qmb                                                     4.92
kbThr                                                      1
mt                                                     172.5
Qmt                                                    172.5
ktThr                                                      1
CKM        0.97428 0.22530 0.003470 0.22520 0.97345 0.041...
MZ                                                   91.1876
MW                                                    80.398
GF                                               1.16638e-05
SIN2TW                                               0.23126
TMC                                                        1
MP                                                     0.938
Comments                               NNPDF3.1 NNLO central
global_nx                                                  0
EScaleVar                                                  1
$ ls
theory_53_info.csv
```

user can also parse the `theoryid` from a fit

```
$vp-checktheory --fit FIT
```

where `FIT` is a valid fit name. If the fit cannot be found locally, the script
will attempt to download it.

The parameters in the above are defined [here](./theoryparamsdefinitions).