Question: 对于国投资本在2020年04月26日到2020年07月28日间指数移动平均线，统计20日线与30日线的死叉次数。（平滑系数 alpha 取 2 / (n + 1)；从前 4n 个数据开始计算；初始值用首个数据点）使用不复权价格，写出指标公式，搜集原始数据，计算得出答案，保留四位小数。注意列出原始数据和关键计算过程。
Formula: EMA_t = \alpha * P_t + (1 - \alpha) * EMA_{t-1}，\alpha = 2 / (n + 1)
Data:
date,close
2019-10-30,12.23
2019-10-31,12.26
2019-11-01,12.37
2019-11-04,12.31
2019-11-05,12.65
2019-11-06,12.51
2019-11-07,12.48
2019-11-08,12.31
2019-11-11,12.03
2019-11-12,12.03
2019-11-13,11.84
2019-11-14,11.91
2019-11-15,11.79
2019-11-18,11.9
2019-11-19,11.98
2019-11-20,11.86
2019-11-21,11.84
2019-11-22,11.83
2019-11-25,12.0
2019-11-26,12.12
2019-11-27,11.93
2019-11-28,11.9
2019-11-29,11.95
2019-12-02,12.0
2019-12-03,11.98
2019-12-04,11.92
2019-12-05,11.87
2019-12-06,11.5
2019-12-09,11.45
2019-12-10,11.37
2019-12-11,11.39
2019-12-12,11.28
2019-12-13,11.71
2019-12-16,11.84
2019-12-17,12.21
2019-12-18,12.2
2019-12-19,12.19
2019-12-20,12.3
2019-12-23,11.96
2019-12-24,12.05
2019-12-25,11.96
2019-12-26,12.17
2019-12-27,12.51
2019-12-30,13.76
2019-12-31,15.14
2020-01-02,15.24
2020-01-03,14.67
2020-01-06,14.54
2020-01-07,14.69
2020-01-08,14.12
2020-01-09,14.29
2020-01-10,14.02
2020-01-13,14.81
2020-01-14,14.37
2020-01-15,14.34
2020-01-16,14.17
2020-01-17,14.25
2020-01-20,14.43
2020-01-21,14.42
2020-01-22,14.75
2020-01-23,13.96
2020-02-03,12.56
2020-02-04,12.44
2020-02-05,12.57
2020-02-06,12.95
2020-02-07,13.22
2020-02-10,13.26
2020-02-11,13.12
2020-02-12,13.31
2020-02-13,13.05
2020-02-14,13.23
2020-02-17,13.8
2020-02-18,13.6
2020-02-19,13.55
2020-02-20,14.45
2020-02-21,14.26
2020-02-24,14.35
2020-02-25,14.35
2020-02-26,14.07
2020-02-27,14.1
2020-02-28,12.96
2020-03-02,13.54
2020-03-03,13.92
2020-03-04,14.32
2020-03-05,14.9
2020-03-06,14.08
2020-03-09,13.54
2020-03-10,14.12
2020-03-11,13.71
2020-03-12,13.68
2020-03-13,13.39
2020-03-16,12.47
2020-03-17,12.55
2020-03-18,12.05
2020-03-19,12.35
2020-03-20,12.92
2020-03-23,12.3
2020-03-24,12.5
2020-03-25,12.68
2020-03-26,12.5
2020-03-27,12.54
2020-03-30,12.36
2020-03-31,12.25
2020-04-01,12.18
2020-04-02,12.4
2020-04-03,12.15
2020-04-07,12.42
2020-04-08,12.35
2020-04-09,12.44
2020-04-10,12.21
2020-04-13,12.16
2020-04-14,12.41
2020-04-15,12.18
2020-04-16,12.2
2020-04-17,12.22
2020-04-20,12.2
2020-04-21,11.94
2020-04-22,11.98
2020-04-23,11.85
2020-04-24,11.63
2020-04-27,11.59
2020-04-28,11.73
2020-04-29,11.7
2020-04-30,11.94
2020-05-06,12.03
2020-05-07,12.08
2020-05-08,12.26
2020-05-11,12.26
2020-05-12,12.14
2020-05-13,12.45
2020-05-14,12.19
2020-05-15,12.11
2020-05-18,12.06
2020-05-19,12.23
2020-05-20,12.25
2020-05-21,12.12
2020-05-22,11.69
2020-05-25,11.68
2020-05-26,11.81
2020-05-27,11.65
2020-05-28,11.86
2020-05-29,11.92
2020-06-01,12.32
2020-06-02,12.22
2020-06-03,12.06
2020-06-04,12.03
2020-06-05,12.15
2020-06-08,12.07
2020-06-09,12.14
2020-06-10,11.94
2020-06-11,11.81
2020-06-12,11.72
2020-06-15,11.69
2020-06-16,11.82
2020-06-17,12.06
2020-06-18,12.03
2020-06-19,12.12
2020-06-22,12.39
2020-06-23,13.14
2020-06-24,12.77
2020-06-29,12.2
2020-06-30,12.73
2020-07-01,12.85
2020-07-02,13.57
2020-07-03,14.31
2020-07-06,15.37
2020-07-07,14.64
2020-07-08,15.29
2020-07-09,15.76
2020-07-10,17.34
2020-07-13,16.74
2020-07-14,16.37
2020-07-15,16.01
2020-07-16,15.05
2020-07-17,14.59
2020-07-20,15.21
2020-07-21,15.01
2020-07-22,15.61
2020-07-23,15.71
2020-07-24,14.32
2020-07-27,14.51
2020-07-28,14.46

Indicator data:
date,20日,30日
2019-12-10,11.847783448484044,11.927500382289084
2019-12-11,11.804185024818898,11.892822938270434
2019-12-12,11.754262641502812,11.853285974511053
2019-12-13,11.75004715183588,11.844041718090986
2019-12-16,11.758614089756271,11.843780962085116
2019-12-17,11.801603224065197,11.867407996789302
2019-12-18,11.839545774154224,11.888865545383542
2019-12-19,11.872922367091917,11.908293574713637
2019-12-20,11.913596427368876,11.933564956990176
2019-12-23,11.918015815238508,11.935270443635972
2019-12-24,11.930585737596745,11.942672350498167
2019-12-25,11.933387095920864,11.943790263369253
2019-12-26,11.955921658214116,11.958384439926077
2019-12-27,12.008691024098486,11.993972540576008
2019-12-30,12.175482355136726,12.107909796022717
2019-12-31,12.45781736893323,12.303528518859961
2020-01-02,12.722787143320542,12.492978291836739
2020-01-03,12.908235986813823,12.633431305266628
2020-01-06,13.063642083307744,12.75643573718491
2020-01-07,13.21853331346891,12.881181818656852
2020-01-08,13.304387283614728,12.961105572291894
2020-01-09,13.398255161365705,13.04684069666016
2020-01-10,13.457468955521353,13.109625167843376
2020-01-13,13.58628143594789,13.219326769917997
2020-01-14,13.66092129919095,13.293563752503934
2020-01-15,13.725595461172762,13.361075768471423
2020-01-16,13.767919702965832,13.413264428570042
2020-01-17,13.813832112207182,13.467247368662298
2020-01-20,13.87251476818745,13.529360441651828
2020-01-21,13.924656218836265,13.586821058319453
2020-01-22,14.003260388470908,13.661864861008521
2020-01-23,13.99914035147368,13.681099386104746
2020-02-03,13.862079365619044,13.608770393452827
2020-02-04,13.726643235560088,13.533365851939744
2020-02-05,13.616486736935318,13.471213216330728
2020-02-06,13.553011809608144,13.437586557212617
2020-02-07,13.521296399169273,13.423548714811805
2020-02-10,13.49641102781982,13.412997184823947
2020-02-11,13.460562358503646,13.394094140641757
2020-02-12,13.446223086265205,13.388668712213258
2020-02-13,13.408487554239947,13.36681911787692
2020-02-14,13.391488739550429,13.357992078013893
2020-02-17,13.43039457387896,13.38650871814203
2020-02-18,13.446547471604774,13.400282349229641
2020-02-19,13.4564000933567,13.409941552505149
2020-02-20,13.551028655894157,13.477042097504818
2020-02-21,13.61854973628519,13.527555510569023
2020-02-24,13.688211666162792,13.580616445371023
2020-02-25,13.75123912652824,13.630254094056763
2020-02-26,13.781597304954122,13.658624797666006
2020-02-27,13.811921371148967,13.687100617171426
2020-02-28,13.730786002468115,13.640190899934561
2020-03-02,13.71261590699496,13.633726970906526
2020-03-03,13.73236677299544,13.652196198589976
2020-03-04,13.788331842233971,13.69528031480998
2020-03-05,13.89420500011645,13.7730041654674
2020-03-06,13.91189976201012,13.792810348340472
2020-03-09,13.876480737056776,13.776500003286248
2020-03-10,13.899673047813273,13.798661293396814
2020-03-11,13.881608948021533,13.79294120995186
2020-03-12,13.862408095829005,13.785654680277547
2020-03-13,13.817416848607195,13.760128571872544
2020-03-16,13.689091434454129,13.676894470461413
2020-03-17,13.580606535934688,13.604191601399387
2020-03-18,13.434834484893289,13.503921175502654
2020-03-19,13.331516914903451,13.42947464805087
2020-03-20,13.29232482776979,13.396605315918558
2020-03-23,13.197817701315524,13.325856585859297
2020-03-24,13.131358872618806,13.27257551580386
2020-03-25,13.088372313321777,13.234344837364903
2020-03-26,13.032336854910179,13.186967751083298
2020-03-27,12.985447630633018,13.145227896174699
2020-03-30,12.925881189620348,13.094568031905364
2020-03-31,12.861511552513647,13.04007977178244
2020-04-01,12.796605690369491,12.984590754248089
2020-04-02,12.75883371985811,12.946875221715956
2020-04-03,12.7008495560621,12.89546391708912
2020-04-07,12.674101979294282,12.864788825664016
2020-04-08,12.643235124123397,12.831576643363112
2020-04-09,12.623879398016406,12.80631363411388
2020-04-10,12.584462312491034,12.767841786751696
2020-04-13,12.544037330349031,12.728626187606427
2020-04-14,12.531271870315791,12.708069659373756
2020-04-15,12.497817406476193,12.674000649091578
2020-04-16,12.46945384395465,12.643419962053413
2020-04-17,12.445696335006588,12.616102545146742
2020-04-20,12.42229668405358,12.589257219653405
2020-04-21,12.376363666524666,12.547369657095121
2020-04-22,12.33861474590327,12.510765163088985
2020-04-23,12.292080008198196,12.468135152567115
2020-04-24,12.229024769322178,12.414061916917623
2020-04-27,12.168165267481971,12.360896631955196
2020-04-28,12.126435242007497,12.32019362344196
2020-04-29,12.085822361816307,12.280181131606994
2020-04-30,12.071934517833801,12.258233961825898
2020-05-06,12.067940754230582,12.243509190095194
2020-05-07,12.06908925382767,12.232960210089054
2020-05-08,12.087271229653606,12.234704712663955
2020-05-11,12.103721588734214,12.236336666685636
2020-05-12,12.107176675521432,12.230121397867208
2020-05-13,12.139826515947961,12.24430711413384
2020-05-14,12.144604943000536,12.240803429351013
2020-05-15,12.141309234143343,12.232364498425142
2020-05-18,12.133565497558262,12.221244208204165
2020-05-19,12.142749735886047,12.221809097997445
2020-05-20,12.152964046754043,12.223627865868579
2020-05-21,12.14982461372985,12.216942197102865
2020-05-22,12.106031793374626,12.182945926322036
2020-05-25,12.065457336862757,12.150497802043196
2020-05-26,12.041128066685353,12.128530201911378
2020-05-27,12.003877774620081,12.097657285659032
2020-05-28,11.990175129418168,12.082324557551999
2020-05-29,11.983491783759295,12.071852005451872
2020-06-01,12.01554018530603,12.087861553487235
2020-06-02,12.035012548610219,12.096386614552577
2020-06-03,12.037392305885437,12.094039091033055
2020-06-04,12.036688276753491,12.089907536772857
2020-06-05,12.047479869443634,12.093784469884286
2020-06-08,12.049624643782337,12.092249987956269
2020-06-09,12.058231820564972,12.095330633894575
2020-06-10,12.046971647177832,12.08530930267557
2020-06-11,12.024402918875182,12.067547412180373
2020-06-12,11.995412164696594,12.045124998491318
2020-06-15,11.966325291868348,12.022213708266072
2020-06-16,11.952389549785648,12.009167662571487
2020-06-17,11.962638164091778,12.012447168212036
2020-06-18,11.96905357703542,12.01357960897255
2020-06-19,11.983429426841571,12.020445440651741
2020-06-22,12.02215043380904,12.044287670287114
2020-06-23,12.128612297255797,12.114978788333106
2020-06-24,12.189696840374292,12.157238221343874
2020-06-29,12.190678093671979,12.159997045773302
2020-06-30,12.242042084750837,12.19677142991696
2020-07-01,12.29994283858409,12.238915208631996
2020-07-02,12.420900663480845,12.324791646784771
2020-07-03,12.600814886006479,12.452869605056723
2020-07-06,12.86454680162491,12.641071566020806
2020-07-07,13.033637582422537,12.770034690793658
2020-07-08,13.248529241239439,12.932613097839228
2020-07-09,13.487716932549969,13.115025156043151
2020-07-10,13.854601034211877,13.387604178233916
2020-07-13,14.129400935715507,13.60388777963818
2020-07-14,14.34279132279022,13.782346632564751
2020-07-15,14.501573101572102,13.92606620465735
2020-07-16,14.553804234755711,13.998578062421393
2020-07-17,14.557251450493261,14.036734316458723
2020-07-20,14.619417979017712,14.112428876687193
2020-07-21,14.65661626673031,14.170336691094473
2020-07-22,14.7474147175179,14.263218194894831
2020-07-23,14.839089506325719,14.35655895651452
2020-07-24,14.789652410485173,14.354200314158746
2020-07-27,14.763018847581824,14.364251906793665
2020-07-28,14.734159909716888,14.370429203129559

Answer: 1.0