मुझे निम्नलिखित डेटा का एक डिस्क्रीट कोसाइन ट्रांसफॉर्म करने की आवश्यकता है:

0.6191342,0.6197224,0.61898607,0.61912596,0.6190106,0.61988443,0.61900085,0.6187835,0.6180295,0.61910814,0.6146555,0.6182434,0.6189235,0.61222005,0.6207976,0.6218684,0.62007576,0.6216523,0.6215335,0.62065303,0.6205161,0.61968786,0.619246,0.6213837,0.62122154,0.6192542,0.61824924,0.61987126,0.62156975,0.62128264,0.6205598,0.62057704,0.62053716,0.62275934,0.6218448,0.6203091,0.6178272,0.6140544,0.6213627,0.62143743,0.6132956,0.61910033,0.61519396,0.62216187,0.6215059,0.6197418,0.615724,0.62262917,0.62247676,0.62028235,0.6186407,0.619341,0.6152448,0.62161505,0.61356294,0.6133514,0.618384,0.6184519,0.6158993,0.6210517,0.61071134,0.62111616,0.61093444,0.62230366,0.6216592,0.61184555,0.61515874,0.6136047,0.6233515,0.618276,0.6159197,0.61444646,0.6185363,0.6162487,0.61572075,0.6194457,0.61314666,0.61829245,0.62141377,0.62105316,0.6124673,0.6179071,0.6186554,0.62159,0.61449164,0.61788505,0.6064126,0.6184563,0.6143939,0.6169126,0.61230534,0.6193385,0.6139966,0.6149371,0.6178339,0.61179554,0.6135024,0.61419034,0.614619,0.6137465,0.6185665,0.6185372,0.6163691,0.6195464,0.6170328,0.61263216,0.6161196,0.6184589,0.622137,0.61809236,0.61836344,0.61896133,0.6169496,0.6195432,0.6197563,0.61895114,0.61758405,0.61847824,0.61592484,0.6179055,0.61649424,0.61602193,0.6174835,0.61842364,0.60891753,0.61700743,0.6159329,0.61829287,0.6166717,0.6159072,0.6157982,0.6081088,0.6191729,0.61839896,0.615376,0.6154309,0.6119571,0.61734617,0.6171004,0.6178271,0.6169227,0.6172922,0.61745894,0.6195544,0.6103485,0.6142039,0.6166354,0.61975944,0.6184104,0.6177316,0.6150697,0.61001426,0.6108277,0.617212,0.6106007,0.61446583,0.61284953,0.6152104,0.6181612,0.61701053,0.6148785,0.61547005,0.62181646,0.618621,0.6161165,0.616407,0.6115453,0.6172732,0.61757433,0.61611485,0.61767805,0.61765575,0.61649793,0.6184486,0.6195102,0.61967367,0.6210996,0.61727804,0.6189702,0.6188129,0.6160338,0.6205609,0.6199804,0.6170756,0.6182058,0.61902076,0.62221605,0.6212938,0.61759907,0.6170265,0.6073142,0.6191233,0.61933994,0.61591357,0.6168009,0.6149173,0.6155775,0.6203353,0.6168877,0.61844844,0.60965574,0.61050487,0.62154305,0.62103915,0.6164665,0.6161686,0.60936993,0.614351,0.6204919,0.61622816,0.61612433,0.61211497,0.61347705,0.6192275,0.6165203,0.6156739,0.61536443,0.6136969,0.6195982,0.6201504,0.61684716,0.6125972,0.61233103,0.6179449,0.6163167,0.6089562,0.60863984,0.61114866,0.6104453,0.6166812,0.61086583,0.6118273,0.6211713,0.6160922,0.60824126,0.60837793,0.61538464,0.6222241,0.60950315,0.61592793,0.60851187,0.613283,0.61787575,0.6204593,0.6155273,0.6085147,0.6164997,0.61334276,0.61671215,0.6086348,0.6089769,0.61735654,0.6203436,0.60964227,0.6184011,0.6144072

अगर मैं ऐप्पल द्वारा प्रदान किए गए त्वरित कार्यों का उपयोग करता हूं, तो मुझे ये परिणाम मिलते हैं:

2.669825,0.23372388,0.034602005,0.14609262,-0.05658116,0.028039198,-0.019894773,-0.12209733,0.022227166,0.0051003816,-0.042596065,-0.04589792,0.01035949,-0.019523097,0.077776365,0.0030713473,-0.078441024,-0.00070093106,0.01997262,0.06481835,-0.004874494,0.023854036,0.029294237,0.011619994,-0.0012118752,0.010400612,0.023407647,-0.05563956,0.038198948,-0.01233741,0.009424317,0.039608873,0.05801,0.028565174,-0.012889689,0.021731874,-0.026493106,-0.048108768,0.0045189788,-0.032068893,-0.017894993,-0.025662154,0.010751593,-0.07121442,0.06277961,0.0022988198,-0.018414639,-0.021932043,-0.020916257,-0.01747331,0.006716689,0.023302665,0.0068657864,-0.019596279,-0.043121584,0.04483221,-0.00012186449,-0.012160094,0.011104634,-0.015813472,0.023498433,0.02872037,0.014691476,0.015423553,-0.032783255,0.028947365,0.03251956,-0.016012289,-0.018248938,0.026564144,-0.034706548,0.012790314,0.002194486,0.04613065,-0.05747463,0.010088965,0.017059956,-0.04142371,-0.040067486,0.0029621175,0.07121314,-0.0064264582,-0.0064690933,-0.040944442,-0.0025974065,0.0075896196,-0.006084161,-0.027271878,0.056449506,-0.01756429,0.020225035,0.05740238,-0.07323427,0.091452986,-0.06606907,-0.00599443,0.03895919,0.0029399507,0.0050259903,-0.017262679,-0.052305933,0.0132182,-0.14926372,0.12026562,0.06996072,0.050748315,0.020096999,-0.017148953,0.006768549,-0.07308701,0.045742266,-0.055744015,0.034470245,-0.06591675,0.012785097,-0.045998022,0.028786233,-0.0006729504,0.026651034,0.016280383,-0.016419016,-0.0235405,-0.011106867,0.0060093636,-0.026253335,-0.020966358,0.049879722,-0.019093664,0.055243053,0.008216016,0.039922368,-0.05096092,0.010148679,-0.011200655,0.044212196,-0.012730424,0.027963173,-0.0050371652,0.0006729523,-0.02703674,-0.040479846,0.0032800399,0.019346198,0.03412081,-0.0062747486,-0.018566221,-0.011666842,0.02345107,-0.07089561,0.023972765,-0.0076217707,0.00794466,-0.008454496,-0.051500462,0.007845432,-0.046568125,-0.018137766,0.026703745,0.035737798,-0.061839998,-0.00884305,0.009104564,0.052314416,0.028979728,-0.017012393,-0.019422699,-0.049617197,0.03505949,0.005899897,0.031378012,0.02203784,0.05013973,-0.014152746,0.029270608,0.049914937,0.01226829,-0.038096413,0.012367716,-0.04856258,0.008609608,-0.014275378,-0.00032820972,0.003259441,0.04173329,0.0026449636,0.020232702,-0.058400147,0.006697319,-0.083465755,0.023861019,-0.019418886,-0.034204446,0.057170536,-0.03352673,-0.020436082,-0.024796713,-0.054371275,0.055950172,-0.01681035,0.018895034,0.042727623,0.040553555,-0.049501,0.003925497,-0.034148764,-0.00027683005,-0.054910377,0.03833572,0.053599093,0.02369698,-0.0021882567,0.04318303,0.0055106683,-0.026357781,-0.0022721058,-0.036762282,0.06495822,0.030521873,0.003908515,-0.052683424,-0.00785333,-0.0245375,-0.006546188,0.03067175,0.046067707,0.0047659995,-0.03191337,0.010508363,-0.0308632,-0.016877536,-0.05901345,0.0061260397,0.008024132,0.052667245,-0.026830386,0.021430418,-0.044398945,-0.02600174,-0.032572,0.06329122,0.032917332,0.0284806,-0.074899085,-0.025770163,-0.015752867,0.0030335134,0.04120659,0.0026583495,-0.005403653,0.009906204,0.029109228,0.015893774,0.0023716427,-0.02794688,-0.033177476,-0.08380169

अगर मैं एक कोड का उपयोग करता हूं जिसे मैं कॉल करता हूं dctA मुझे यह मिलता है:

0.16686402,-0.235977,0.23596367,-0.23594144,0.23591036,-0.23587029,0.23582156,-0.23576365,0.23569722,-0.23562174,0.23553737,-0.2354442,0.23534207,-0.2352311,0.2351113,-0.23498271,0.23484512,-0.23469894,0.23454358,-0.2343797,0.2342069,-0.23402523,0.23383485,-0.23363559,0.2334273,-0.23321046,0.2329848,-0.23275039,0.23250724,-0.23225537,0.23199482,-0.2317253,0.23144716,-0.23116058,0.23086505,-0.23056087,0.23024791,-0.22992653,0.22959618,-0.22925732,0.22890992,-0.22855341,0.22818917,-0.22781523,0.22743407,-0.22704314,0.22664468,-0.22623657,0.22582,-0.225396,0.22496259,-0.22452155,0.22407113,-0.22361335,0.22314598,-0.22267129,0.22218716,-0.22169586,0.2211951,-0.22068696,0.22016953,-0.21964486,0.21911088,-0.21856976,0.21801907,-0.21746023,0.21689478,-0.21631947,0.21573758,-0.21514617,0.2145479,-0.2139403,0.2133261,-0.21270223,0.212072,-0.21143214,0.2107861,-0.21013027,0.20946832,-0.20879678,0.20811911,-0.20743181,0.20673671,-0.2060339,0.2053268,-0.20460844,0.20388247,-0.20314853,0.20241094,-0.20166187,0.20090508,-0.20014101,0.19937299,-0.19859369,0.19780688,-0.19701274,0.19621103,-0.19540597,0.19458961,-0.19376592,0.19293484,-0.19210072,0.19125515,-0.19040233,0.18954237,-0.18867959,0.18780532,-0.18692416,0.18603577,-0.1851449,0.18424252,-0.1833334,0.18241717,-0.1814941,0.18056883,-0.17963219,0.17868869,-0.1777385,0.17678645,-0.17582284,0.17485264,-0.17387584,0.1728974,-0.17190763,0.17091122,-0.1699084,0.16890429,-0.16788879,0.16686694,-0.16583884,0.16480431,-0.16376887,0.16272213,-0.16166915,0.16061012,-0.15955035,0.15847927,-0.15740223,0.15631929,-0.15523578,0.15414095,-0.15304045,0.15193413,-0.15082765,0.14970991,-0.14858656,0.1474576,-0.14632308,0.14518869,-0.14404319,0.14289224,-0.14173594,0.14057998,-0.13941304,0.13824077,-0.13706335,0.13588662,-0.1346989,0.13350609,-0.13230827,0.13111141,-0.12990372,0.12869103,-0.12747958,0.12625119,-0.1250302,0.12379233,-0.122562,0.121327065,-0.120075285,0.118831374,-0.11758294,0.11631756,-0.11506039,0.11378633,-0.112520546,0.11125048,-0.10996368,0.10868541,-0.10739021,0.10610382,-0.104813375,0.10350613,-0.102208,0.100905985,-0.09958719,0.098277606,-0.096951276,0.09563441,-0.09431398,0.092976734,-0.09164931,0.090305135,-0.088970825,0.087633155,-0.086278856,0.08493474,-0.08358737,0.08222347,-0.0808699,0.079499744,-0.07814017,0.07677769,-0.07539867,0.07403045,-0.07265948,0.07127206,-0.069895685,0.0685029,-0.06712131,0.06573725,-0.06433683,0.062947854,-0.061542634,0.06014901,-0.05875311,0.057341076,-0.055940807,0.054538473,-0.053120058,0.05171367,-0.05029129,0.048881073,-0.047469016,0.046041086,-0.044625536,0.043194164,-0.041775327,0.0403549,-0.038918786,0.0374954,-0.03607061,0.03463024,-0.033202793,0.031759836,-0.030329958,0.028898928,-0.027452547,0.026019417,-0.024585323,0.02313597,-0.021700067,0.020249018,-0.018811548,0.017373376,-0.015920186,0.014480768,-0.013026423,0.0115859695,-0.0101450775,0.00868942,-0.0072478293,0.0058059655,-0.0043494827,0.0029072375,-0.0014504795

और अगर मैं वेब पर मिले किसी अन्य कोड का उपयोग करता हूं, जिसे मैं dctB कॉल करता हूं, तो मुझे यह मिलता है:

0.23598135,0.0065520015,-0.0014035295,-0.0014900116,-0.0029997544,-0.0022787564,0.003723558,-0.003108655,-0.0012933733,-0.0007105355,0.0012699091,-0.00060556503,0.0053185527,0.00076327357,-0.0011331664,0.005722867,0.0034567474,-0.0011424342,-0.0013203556,0.0021249577,-0.0029971765,0.0006293817,0.0019937858,0.0026412704,0.00016487329,-0.003959481,0.00039281833,-0.0024429162,0.00060916966,-0.0019161169,-0.006625204,-0.002263753,0.00040166255,-0.0013965253,-0.00019885821,-0.010229679,0.0015206567,-0.0053624627,0.00058637373,0.0070882766,-0.0044516595,0.0010087036,-0.0064169616,0.0043392666,0.0012746729,0.0014619434,-0.0050648195,0.0009482073,0.004468296,-0.0015502489,-0.0043041282,-0.001236145,0.0048462045,-0.003547573,0.0035744759,0.0021012123,0.0039755865,0.0017270996,-0.0047634826,0.0021218802,0.003715937,-0.0038134162,-0.0031784503,0.0021606751,0.0063801087,-6.5251596e-05,-0.004479158,-0.0052841934,0.0056381524,0.0003858073,-0.00277002,0.001508747,0.005996452,-0.0019169269,0.001555898,0.00014130188,0.005808804,0.0037767508,-0.0026520337,-0.0018158474,0.0033173792,0.0046277773,-0.0006036768,-0.0019087599,9.9361154e-05,0.004506388,-0.0044565895,0.00051484356,-0.0026925507,0.005224032,8.564865e-05,-0.0057873107,-0.000118939184,-0.0065063527,0.004078492,0.0003850522,-0.0038591337,0.0016885462,-0.0028994652,0.00063551,0.0018036738,-0.0020673752,-1.50109045e-05,0.0007685168,-0.0028343478,0.003231319,0.0062061716,0.0032275403,-0.002344687,0.000663079,-0.0016223937,-0.0045130113,0.0058470825,0.00283345,-0.0020404255,-9.103818e-05,0.004184909,-0.003951648,-0.00038761974,0.0010700208,-0.0066716103,-0.00018829755,0.0036042533,-0.0043730726,-0.002380092,0.0013307306,-0.0021570993,0.007163353,0.16732568,0.0021171984,0.00011411852,-0.00347561,-0.0018730971,0.0011592627,0.0017720436,-0.0042686476,0.004867761,-0.002120747,0.002259214,0.003109498,0.0034014524,0.0012342912,0.00042545033,0.005238078,-0.0009351839,0.0028766692,-0.0002561589,0.0023975722,-0.0019213242,-0.0023478842,-0.0033766865,0.0005857277,0.0030684788,-0.006383024,0.00048669687,-0.0014512719,-0.0009451752,-0.0033242197,-0.006483069,-0.004888436,0.00435442,-0.0022291946,-0.0043107485,-0.007959526,0.0022944517,-0.0017021666,0.000734793,0.0049511404,-0.003661971,0.00094925304,-0.004634777,0.0016841891,0.0016499859,0.003999946,-0.0065253885,-0.0033514274,0.003085088,-0.0003703781,-0.003465078,-0.0054242075,0.0009584457,-0.005197831,0.003603162,0.0048823943,-0.00041171763,0.0009989656,-0.0040209224,0.002628903,-0.0003624089,-0.0002924401,-3.2498552e-05,0.0031572247,0.0026128257,-0.0022803256,-0.0030580086,-0.00357484,0.0042991657,-0.0015585661,0.00086751115,0.0004323435,0.0045290007,-0.0048501627,-0.001418146,0.00370478,0.003376496,0.006685608,0.00055006717,-0.0011108073,0.00024791225,0.0055819694,0.0041101393,-0.0041453117,-0.0011638473,0.0020769653,-8.08032e-06,-0.0002288826,0.0006749544,0.00035142386,-0.00043356852,-0.0029805794,-0.0017968996,0.0010227,0.006042389,0.0017817094,-0.0056505343,0.004619073,0.0023046366,0.0027151196,0.0020018944,-0.00041239324,-0.00031199362,0.0050316383,-0.0041035055,0.001887646,0.0069080763,0.0039198315,-0.0003352705,-0.0012968663,-0.0009449865,-0.0052614617,0.004834936,-0.0014728566,-0.0017496345,-0.0008812858,0.00056978094,-0.005053855,-0.0017934664,0.0021964775,-0.008228115,0.0029420764,0.0012297969,-0.0038868873,-0.0003670447,0.0032279065,-0.0016167451,0.0036267326

ये 3 कोड क्रम में हैं:

let DCTSetupForward = vDSP_DCT_CreateSetup(nil,
                                           vDSP_Length(numberSamples),
                                           vDSP_DCT_Type.II)
var output = Array<Float>(repeating:0.0,
                       count: numberSamples)

vDSP_DCT_Execute(DCTSetupForward!, data, &output)



func dctA (_ data:[Float] = []) -> Array<Float> {

let numberSamples = data.count
var c = [Float](repeating: 0,
                         count: numberSamples)


for i in 0..< numberSamples {
  var sum : Float = 0
  let s : Float = (i == 0) ? sqrt(0.5) : 1
  for j in 0..< numberSamples {
    sum = sum + s * data[j] * cos(Float.pi * (numberSamples + 0.5) * Float(i) / numberSamples)
  }
  c[i] = sum * sqrt(2.0 / numberSamples)
}

return c;
}


func dctB (_ data:[Float] = []) -> Array<Float> {
var angle : Float
var c :[Float] = []

let numberSamples = data.count

for i in 0..<numberSamples {
  c.append(0)
  for j in 0..< numberSamples {
    let fk = Float(2*j + 1)
    let y = Float.pi * Float(i) * fk
    let fky = fk * y
    let x = Float(2 * numberSamples)
    angle = fky / x

    c[i] = c[i] + cos ( angle ) * data[j];
  }
  c[i] = c[i] * sqrt (2.0/Float(numberSamples));
}

return c;
}

मैंने पिछले दो कोडों में अंतर देखा है। तो, मेरे पास 3 प्रश्न हैं:

  1. मेरे पास इस डेटा के DCT के लिए 3 अलग-अलग परिणाम क्यों हैं?
  2. क्या मैथलैब वाला कोई जांच सकता है कि कौन सा सही है?
  3. पिछले दो कोड में अंतर क्यों?
0
DuckDucking 14 फरवरी 2019, 18:21

1 उत्तर

सबसे बढ़िया उत्तर

विकिपीडिया के माध्यम से खोजना और उपरोक्त का सूत्र टाइप II के लिए भिन्न है।

यदि आप नीचे दिए गए सुधार का अनुसरण करते हैं, तो त्रुटि मुख्य रूप से गुणा और योग के दौरान गोल करने से आती है।

   let DCTSetupForward = vDSP_DCT_CreateSetup(nil,
                                               vDSP_Length(numberSamples),
                                               vDSP_DCT_Type.II)
    var output = Array<Float>(repeating:0.0,
                              count: numberSamples)

    vDSP_DCT_Execute(DCTSetupForward!, data, &output)
    print(output)


    func dctA (_ data:[Float] = []) -> Array<Float> {

        let numberSample =  data.count
        var c = [Float](repeating: 0,
                        count: numberSample)


        for i in 0..<numberSample {
            var sum : Float = 0
            let s : Float = (i == 0) ? 1  : 1
            for j in 0..<numberSample {
                sum = sum + s * data[j] * cos(Float.pi * (Float(j) + 0.5) * Float(i) / Float(numberSample))
            }
            c[i] = sum
        }

        return c;
    }


    func dctB (_ data:[Float] = []) -> Array<Float> {
        var angle : Float
        var c :[Float] = []

        let numberSampl = data.count

        for i in 0..<numberSampl {
            c.append(0)
            for j in 0..<numberSampl {
                let fk = Float(2*j + 1)
                let y = Float.pi * Float(i) * fk
               // let fky = fk * y
                let x = Float(2 * numberSampl)
                angle = y / x

                c[i] = c[i] + cos ( angle ) * data[j];
            }

        }

        return c;
    }
1
E.Coms 14 फरवरी 2019, 18:04