| 1 | #pragma rtGlobals=1 // Use modern global access method. |
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| 2 | |
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| 3 | |
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| 4 | //////////////////////////////////////////////// |
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| 5 | // this procedure is for the Teubner-Strey Model |
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| 6 | // |
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| 7 | // 06 NOV 98 SRK |
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| 8 | //////////////////////////////////////////////// |
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| 9 | |
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| 10 | Proc PlotTeubnerStreyModel(num,qmin,qmax) |
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| 11 | Variable num=128,qmin=0.001,qmax=0.7 |
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| 12 | Prompt num "Enter number of data points for model: " |
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| 13 | Prompt qmin "Enter minimum q-value (^-1) for model: " |
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| 14 | Prompt qmax "Enter maximum q-value (^-1) for model: " |
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| 15 | |
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| 16 | Make/O/D/n=(num) xwave_ts,ywave_ts |
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| 17 | xwave_ts = alog(log(qmin) + x*((log(qmax)-log(qmin))/num)) |
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| 18 | Make/O/D coef_ts = {0.1,-30,5000,0.1} |
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| 19 | make/o/t parameters_ts = {"scale (a2)","c1","c2","bkg"} |
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| 20 | Edit parameters_ts,coef_ts |
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| 21 | ywave_ts := TeubnerStreyModel(coef_ts,xwave_ts) |
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| 22 | Display ywave_ts vs xwave_ts |
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| 23 | ModifyGraph log=1,marker=29,msize=2,mode=4 |
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| 24 | Label bottom "q (\\S-1\\M)" |
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| 25 | Label left "Intensity (cm\\S-1\\M)" |
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| 26 | AutoPositionWindow/M=1/R=$(WinName(0,1)) $WinName(0,2) |
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| 27 | End |
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| 28 | |
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| 29 | /////////////////////////////////////////////////////////// |
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| 30 | |
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| 31 | Proc PlotSmearedTeubnerStreyModel() |
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| 32 | //no input parameters necessary, it MUST use the experimental q-values |
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| 33 | // from the experimental data read in from an AVE/QSIG data file |
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| 34 | |
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| 35 | // if no gQvals wave, data must not have been loaded => abort |
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| 36 | if(ResolutionWavesMissing()) |
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| 37 | Abort |
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| 38 | endif |
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| 39 | |
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| 40 | // Setup parameter table for model function |
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| 41 | Make/O/D smear_coef_ts = {0.1,-30,5000,0.1} |
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| 42 | make/o/t smear_parameters_ts = {"scale (a2)","c1","c2","bkg"} |
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| 43 | Edit smear_parameters_ts,smear_coef_ts |
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| 44 | |
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| 45 | // output smeared intensity wave, dimensions are identical to experimental QSIG values |
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| 46 | // make extra copy of experimental q-values for easy plotting |
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| 47 | Duplicate/O $gQvals smeared_ts,smeared_qvals |
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| 48 | SetScale d,0,0,"1/cm",smeared_ts |
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| 49 | |
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| 50 | smeared_ts := SmearedTeubnerStreyModel(smear_coef_ts,$gQvals) |
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| 51 | Display smeared_ts vs smeared_qvals |
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| 52 | ModifyGraph log=1,marker=29,msize=2,mode=4 |
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| 53 | Label bottom "q (\\S-1\\M)" |
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| 54 | Label left "Intensity (cm\\S-1\\M)" |
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| 55 | AutoPositionWindow/M=1/R=$(WinName(0,1)) $WinName(0,2) |
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| 56 | End |
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| 57 | |
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| 58 | /////////////////////////////////////////////////////////////// |
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| 59 | // unsmeared model calculation |
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| 60 | /////////////////////////// |
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| 61 | Function TeubnerStreyModel(w,x) : FitFunc |
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| 62 | Wave w;Variable x |
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| 63 | |
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| 64 | //Varialbes are: |
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| 65 | //[0] scale factor a2 |
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| 66 | //[1] coeff c1 |
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| 67 | //[2] coeff c2 |
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| 68 | //[3] incoh. background |
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| 69 | |
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| 70 | Variable inten,q2,q4 |
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| 71 | |
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| 72 | q2 = x*x |
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| 73 | q4 = q2*q2 |
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| 74 | inten = 1.0/(w[0]+w[1]*q2+w[2]*q4) |
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| 75 | inten += w[3] |
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| 76 | |
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| 77 | return (inten) |
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| 78 | |
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| 79 | End |
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| 80 | |
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| 81 | Macro TeubnerStreyLengths() |
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| 82 | If(exists("coef_ts")!=1) //coefficients don't exist |
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| 83 | Abort "You must plot the Teubner-Strey model before calculating the lengths" |
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| 84 | Endif |
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| 85 | // calculate the correlation length and the repeat distance |
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| 86 | Variable a2,c1,c2,xi,dd |
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| 87 | a2 = coef_ts[0] |
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| 88 | c1 = coef_ts[1] |
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| 89 | c2 = coef_ts[2] |
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| 90 | |
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| 91 | xi = 0.5*sqrt(a2/c2) + c1/4/c2 |
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| 92 | xi = 1/sqrt(xi) |
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| 93 | |
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| 94 | dd = 0.5*sqrt(a2/c2) - c1/4/c2 |
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| 95 | dd = 1/sqrt(dd) |
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| 96 | dd *=2*Pi |
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| 97 | |
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| 98 | Printf "The correlation length (the dispersion of d) xi = %g A\r",xi |
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| 99 | Printf "The quasi-periodic repeat distance, d = %g A\r",dd |
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| 100 | |
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| 101 | End |
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| 102 | // this is all there is to the smeared calculation! |
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| 103 | Function SmearedTeubnerStreyModel(w,x) :FitFunc |
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| 104 | Wave w |
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| 105 | Variable x |
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| 106 | |
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| 107 | Variable ans |
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| 108 | SVAR sq = gSig_Q |
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| 109 | SVAR qb = gQ_bar |
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| 110 | SVAR sh = gShadow |
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| 111 | SVAR gQ = gQVals |
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| 112 | |
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| 113 | //the name of your unsmeared model is the first argument |
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| 114 | ans = Smear_Model_20(TeubnerStreyModel,$sq,$qb,$sh,$gQ,w,x) |
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| 115 | |
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| 116 | return(ans) |
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| 117 | End |
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