3 @brief Declaration of a Harmonic class */
4 #ifndef FLOW_HARMONIC_H
5 #define FLOW_HARMONIC_H
6 #include <flow/AliFMDFlowStat.h>
8 /** @defgroup a_basic Basic classes for doing Flow analysis.
9 @brief This group of class handles the low-level stuff to do
11 //______________________________________________________
12 /** @class AliFMDFlowHarmonic flow/AliFMDFlowHarmonic.h <flow/AliFMDFlowHarmonic.h>
13 @brief Calculate the @f$ n^{th}@f$ order harmonic
16 Calculate the @f$ n^{th}@f$ order harmonic, given by
18 v_n &=& \frac{v_n^{obs}}{R}\\
19 v_n^{obs} &=& \frac1M\sum_i^M\cos(n (\varphi_i - \Psi))
21 where @f$ R@f$ is the resolution, @f$ i@f$ runs over all @f$
22 M@f$ observations of @f$ \varphi_i@f$ in all events, and
23 @f$\Psi@f$ is the estimated event plane.
25 The error on the corrected value is given by
27 \delta^2v_n & = & \left(\frac{dv_n}{dv_n^{obs}}\right)^2\delta^2
28 v_n^{obs} + \left(\frac{dv_n}{dR}\right)^2\delta^2R \\
29 & = & \frac{\delta^2v_n^{obs} R^2 + \delta^2R (v_n^{obs})^2}
33 class AliFMDFlowHarmonic : public AliFMDFlowStat
37 @param n Order of the harmonic */
38 AliFMDFlowHarmonic(UShort_t n) : fOrder(n) {}
40 virtual ~AliFMDFlowHarmonic() {}
42 @param phi The absolute angle @f$ \varphi \in[0,2\pi]@f$
43 @param psi The event plane angle @f$ \Psi \in[0,2\pi] @f$ */
44 void Add(Double_t phi, Double_t psi);
46 @param r Event plane resolution
47 @param er2 Square error on event plane resolution
48 @param e2 On return the square error
49 @return The harmonic value */
50 Double_t Value(Double_t r, Double_t er2, Double_t& e2) const;
51 /** Get the order of the harmonic */
52 UShort_t Order() const { return fOrder; }
56 /** Define for ROOT I/O */
57 ClassDef(AliFMDFlowHarmonic,1);