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EcalEBPhase2TimeReconstructor.h
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1 #ifndef SimCalorimetry_EcalEBTrigPrimAlgos_EcalEBPhase2TimeReconstructor_h
2 #define SimCalorimetry_EcalEBTrigPrimAlgos_EcalEBPhase2TimeReconstructor_h
3 
4 #include <vector>
5 #include <cstdint>
6 
9 
17 private:
18  static const int maxSamplesUsed_ = 12;
19  bool debug_;
24  int shift_;
25  bool extraShift_[2] = {false, false};
26  int setInput(int input);
27  void process();
29 
30  // The array invAmpPar is pre-calulated, at least for now since it has shown to be stable. We might decide at a later stage
31  // to make the calculation dynamic in CMSSW.
32  // Here some explnation of what this LUT is.
33 
34  //The sum of the digis multiplied by the time weight coefficients gives dT*A, where A is the amplitude.
35  //So to get dT the amplitude, calculated in EcalEBPhase2AmplitudeReconstructor, must be divided off of the result here.
36  //However, when this is implemented into the BCP hardware (of which we are emulating the behaviour),
37  //division is not a trivial operation, often requiring relatively large
38  //amounts of time and resources to complete.
39  //To optimize this operation, we instead use an approximation of that division via a lookup table (LUT).
40  //Think about the division as a multiplication of 1/A, then the LUT is filled with all the possible values of 1/A,
41  //precalculated, in the range that A takes and A itself is used to index the LUT.
42  //The element received is then multiplied by the dT*A result in order to get a measurement of the timing.
43 
44  //Another limitation of hardware is that we do not use floating point numbers.
45  //So, instead, each element of the LUT is bit shifted to the left by some amount sufficient to make every element
46  //of the LUT large enough such that converting it to an integer doesn't lead to a loss in performance
47  //(this bit shift is undone after the multiplication by a corresponding bit shift to the right).
48  //Another method of approximation used here is that not every element in A's range is included in the LUT.
49  //Instead, every 8th element is used, since the difference between, e.g., dividing by 1000 and 1008 is generally
50  //small whereas it can be a significant save in time and resources in hardware to use a smaller LUT.
51  //Note that this requires the indexing amplitude to be bit shifted by 3 to the right to compensate for the smaller size of the LUT.
52  //Finally, dT will be in units of ns, but to convert it to ps each element of the LUT is multiplied by 1000.
53 
54  //The pre-calculation of the LUT is given by:
55  //invAmpAr_ = [1000*invMult] #Since 1/0 is undefined, the array starts with 1/1. The rest of the elements will be filled in the following loop:
56  //for i in range(8,4096,8): #loop is set to do every 8th number, so 1/8, 1/16, 1/24, etc. 4096 is the expected range of A
57  //invAmpAr_.append(round((ns_to_ps_conv/i)*invMult))
58  //Where ns_to_ps_conv = 1000 #this is to convert the resulting dT from units of ns to units of ps
59  //invMult = 2**18 #Acts as a shift by 18 bits that is done to the fractions to make them integers instead of floats.
60 
62  262144000, 32768000, 16384000, 10922667, 8192000, 6553600, 5461333, 4681143, 4096000, 3640889, 3276800, 2978909,
63  2730667, 2520615, 2340571, 2184533, 2048000, 1927529, 1820444, 1724632, 1638400, 1560381, 1489455, 1424696,
64  1365333, 1310720, 1260308, 1213630, 1170286, 1129931, 1092267, 1057032, 1024000, 992970, 963765, 936229,
65  910222, 885622, 862316, 840205, 819200, 799220, 780190, 762047, 744727, 728178, 712348, 697191,
66  682667, 668735, 655360, 642510, 630154, 618264, 606815, 595782, 585143, 574877, 564966, 555390,
67  546133, 537180, 528516, 520127, 512000, 504123, 496485, 489075, 481882, 474899, 468114, 461521,
68  455111, 448877, 442811, 436907, 431158, 425558, 420103, 414785, 409600, 404543, 399610, 394795,
69  390095, 385506, 381023, 376644, 372364, 368180, 364089, 360088, 356174, 352344, 348596, 344926,
70  341333, 337814, 334367, 330990, 327680, 324436, 321255, 318136, 315077, 312076, 309132, 306243,
71  303407, 300624, 297891, 295207, 292571, 289982, 287439, 284939, 282483, 280068, 277695, 275361,
72  273067, 270810, 268590, 266407, 264258, 262144, 260063, 258016, 256000, 254016, 252062, 250137,
73  248242, 246376, 244537, 242726, 240941, 239182, 237449, 235741, 234057, 232397, 230761, 229147,
74  227556, 225986, 224438, 222912, 221405, 219919, 218453, 217007, 215579, 214170, 212779, 211406,
75  210051, 208713, 207392, 206088, 204800, 203528, 202272, 201031, 199805, 198594, 197398, 196216,
76  195048, 193893, 192753, 191626, 190512, 189410, 188322, 187246, 186182, 185130, 184090, 183061,
77  182044, 181039, 180044, 179060, 178087, 177124, 176172, 175230, 174298, 173376, 172463, 171560,
78  170667, 169782, 168907, 168041, 167184, 166335, 165495, 164663, 163840, 163025, 162218, 161419,
79  160627, 159844, 159068, 158300, 157538, 156785, 156038, 155299, 154566, 153840, 153121, 152409,
80  151704, 151005, 150312, 149626, 148945, 148271, 147604, 146942, 146286, 145636, 144991, 144352,
81  143719, 143092, 142470, 141853, 141241, 140635, 140034, 139438, 138847, 138262, 137681, 137105,
82  136533, 135967, 135405, 134848, 134295, 133747, 133203, 132664, 132129, 131598, 131072, 130550,
83  130032, 129518, 129008, 128502, 128000, 127502, 127008, 126517, 126031, 125548, 125069, 124593,
84  124121, 123653, 123188, 122727, 122269, 121814, 121363, 120915, 120471, 120029, 119591, 119156,
85  118725, 118296, 117871, 117448, 117029, 116612, 116199, 115788, 115380, 114975, 114573, 114174,
86  113778, 113384, 112993, 112605, 112219, 111836, 111456, 111078, 110703, 110330, 109960, 109592,
87  109227, 108864, 108503, 108145, 107789, 107436, 107085, 106736, 106390, 106045, 105703, 105363,
88  105026, 104690, 104357, 104025, 103696, 103369, 103044, 102721, 102400, 102081, 101764, 101449,
89  101136, 100825, 100515, 100208, 99902, 99599, 99297, 98997, 98699, 98402, 98108, 97815,
90  97524, 97234, 96947, 96661, 96376, 96094, 95813, 95534, 95256, 94980, 94705, 94432,
91  94161, 93891, 93623, 93356, 93091, 92827, 92565, 92304, 92045, 91787, 91531, 91276,
92  91022, 90770, 90519, 90270, 90022, 89775, 89530, 89286, 89043, 88802, 88562, 88323,
93  88086, 87850, 87615, 87381, 87149, 86918, 86688, 86459, 86232, 86005, 85780, 85556,
94  85333, 85112, 84891, 84672, 84454, 84237, 84021, 83806, 83592, 83379, 83168, 82957,
95  82747, 82539, 82332, 82125, 81920, 81716, 81512, 81310, 81109, 80909, 80709, 80511,
96  80314, 80117, 79922, 79727, 79534, 79341, 79150, 78959, 78769, 78580, 78392, 78205,
97  78019, 77834, 77649, 77466, 77283, 77101, 76920, 76740, 76561, 76382, 76205, 76028,
98  75852, 75677, 75502, 75329, 75156, 74984, 74813, 74642, 74473, 74304, 74136, 73968,
99  73802, 73636, 73471, 73306, 73143, 72980, 72818, 72656, 72496, 72336, 72176, 72018,
100  71860, 71702, 71546, 71390, 71235, 71080, 70926, 70773, 70621, 70469, 70318, 70167,
101  70017, 69868, 69719, 69571, 69424, 69277, 69131, 68985, 68840, 68696, 68552, 68409,
102  68267, 68125, 67983, 67843, 67702, 67563, 67424, 67285, 67148, 67010, 66873, 66737,
103  66602, 66467, 66332, 66198, 66065, 65932, 65799, 65667, 65536, 65405, 65275, 65145,
104  65016, 64887, 64759, 64631, 64504, 64377, 64251, 64125};
105 
106 public:
109  virtual void process(std::vector<int> &addout, std::vector<int> &ampRecoOutput, std::vector<int64_t> &output);
110  void setParameters(uint32_t raw,
111  const EcalEBPhase2TPGTimeWeightIdMap *ecaltpgTimeWeightMap,
112  const EcalTPGWeightGroup *ecaltpgWeightGroup);
113 };
114 
115 #endif
static std::string const input
Definition: EdmProvDump.cc:50
#define debug
Definition: HDRShower.cc:19
unsigned long long uint64_t
Definition: Time.h:13
Definition: output.py:1
void setParameters(uint32_t raw, const EcalEBPhase2TPGTimeWeightIdMap *ecaltpgTimeWeightMap, const EcalTPGWeightGroup *ecaltpgWeightGroup)