1) run simu/digi/reco with multi kalman in order to have all the pid hypo for all the particle

2) run dedx_p_chain.C"(int ifile)" with ifile = 0, 1, 2, 3, 4 for e, mu, pi, k, p to fill the dedx vs p histos.
   It takes the correct pid hypo genfitted track and fills the correct band (takes muon hypo for mu, electron for e...).
   This creates the band you can use to parametrize them. 

3) run dedx_bands.C changing the ifile: it fits the histo dedx vs p and in the end you have the parameters for the band of the given particle. STANDARD PROCEDURE:

// @ fixed momentum, the de/dx_mean values distribute as a gaussian:
// its mean and sigma is evaluated from the distribution of de/dx 
// from truncated mean vs momentum from global tracking for the 
// different particles.
//
// The candidate pid is evaluated as the probability density function 
// value of the gaussian @ the reconstructed momentum, evaluated for 
// the measured dedx_mean of the track.

4) draw_bands.C to draw them on the histos: fill in the correct parameters coming from dedx_bands.C

5) run run_pid_sttcombi.C to have the candidates 

6) run run_algo_stt.C (PndPidSttAssociatorTask) to obtain pid info from STT

=============
for the last parametrization 22/03/2011
- same function for mean and sigma
- truncated mean @ 70%

ifile 0
 momentum sampled over 50 with step width 0.03

MEAN DEDX PARAMETRIZATION
mom limits 0.12 1.23
mu: -0.0051344, 0.163231, 7.30319,

SIGMA DEDX PARAMETRIZATION
mom limits 0.12 1.23
sig: 0.00428134, -0.00359152, 0.655438,
-------------------------

ifile 1
 momentum sampled over 50 with step width 0.03

MEAN DEDX PARAMETRIZATION
mom limits 0.12 1.23
mu: 0.0737857, 0.643465, 5.42333,

SIGMA DEDX PARAMETRIZATION
mom limits 0.12 1.23
sig: 0.0193587, -0.0174329, 0.539616,
-------------------------

ifile 2
 momentum sampled over 50 with step width 0.03

MEAN DEDX PARAMETRIZATION
mom limits 0.12 1.23
mu: 0.124558, 0.585125, 5.20178,

SIGMA DEDX PARAMETRIZATION
mom limits 0.12 1.23
sig: 0.0395417, -0.0443629, 0.502671,
-------------------------

ifile 3
 momentum sampled over 50 with step width 0.03

MEAN DEDX PARAMETRIZATION
mom limits 0.3 1.23
mu: 1.71069, 2.21786, 3.82597,

SIGMA DEDX PARAMETRIZATION
mom limits 0.3 1.23
sig: 0.260654, 0.385838, 0.307763,
-------------------------
ifile 4
 momentum sampled over 50 with step width 0.03

MEAN DEDX PARAMETRIZATION
mom limits 0.39 1.23
mu: 4.26561, -0.152697, 4.03156,

SIGMA DEDX PARAMETRIZATION
mom limits 0.39 1.23
sig: 0.338277, -0.664876, 0.656844,