1 | function GUI_input=FFT(hget_field) |
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2 | global spec x_vec |
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3 | %requests for the visibility of input windows in the GUI series (activated directly by the selection in the menu ACTION) |
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4 | if ~exist('hget_field','var') |
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5 | GUI_input={'check_1Dplot'}; |
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6 | return %exit the function |
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7 | end |
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8 | GUI_input=[]; |
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9 | %initiation |
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10 | hhget_field=guidata(hget_field); |
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11 | % testinterp=0; |
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12 | abscissa_list=get(hhget_field.abscissa,'String'); |
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13 | val=get(hhget_field.abscissa,'Value'); |
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14 | val=val(1); |
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15 | abscissa_name=abscissa_list{val}; |
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16 | ordinate_list=get(hhget_field.ordinate,'String'); |
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17 | val=get(hhget_field.ordinate,'Value'); |
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18 | val=val(1); %take only the first variable in the list |
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19 | |
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20 | %ordinate_name=Field.ListVarName{val}; |
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21 | ordinate_name=ordinate_list{val}; |
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22 | |
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23 | [Field,errormsg]=read_get_field(hget_field); |
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24 | if ~isempty(errormsg) |
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25 | msgbox_uvmat('ERROR',['error in get_field/FFT input:' errormsg]) |
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26 | return |
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27 | end |
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28 | |
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29 | % get variable |
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30 | eval(['Var= Field.' ordinate_name ';']); |
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31 | np=size(Var) |
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32 | np_freq=floor(np(1)/2); |
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33 | dx=1;%default |
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34 | dfreq=1/np(1);%default frequency interval (abscissa= array index) |
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35 | sum_data=sum(Var,2); |
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36 | if ~isequal(abscissa_name,'') |
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37 | eval(['Coord_x= Field.' abscissa_name ';']); |
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38 | ind_select=find(~isinf(Coord_x)&~isnan(sum_data));%detect infinite values |
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39 | Coord_x=Coord_x(ind_select); |
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40 | Var=Var(ind_select,:); |
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41 | diff_x=diff(Coord_x); |
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42 | dx=min(diff_x); |
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43 | %interpolate on a regular abscissa interval if needed |
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44 | if (max(diff_x)-dx)> 0.001*dx || numel(ind_select)<np(1) |
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45 | xequ=Coord_x(1):dx:Coord_x(end);%equal time spacingdx= |
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46 | Var=interp1(Coord_x,Var,xequ); %interpolated func |
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47 | np=size(Var); |
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48 | end |
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49 | % funcinterp=interp1(time,func,timeq); %interpolated func |
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50 | dfreq=1/(Coord_x(end)-Coord_x(1));%frequency interval |
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51 | end |
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52 | freq_max=1/(2*dx); |
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53 | Var=Var-ones(np(1),1)*mean(Var,1); %substract mean value |
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54 | fourier=fft(Var);%take fft (complex) |
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55 | spec=abs(fourier).*abs(fourier);% take square of the modulus |
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56 | spec=spec(1:np_freq,:);%keep only the first half (the other is symmetric) |
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57 | |
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58 | %plot |
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59 | list_fig=get(hhget_field.list_fig,'String'); |
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60 | val=get(hhget_field.list_fig,'Value'); |
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61 | hfig=str2num(list_fig{val})% chosen figure number from tyhe GUI |
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62 | if isempty(hfig) |
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63 | hfig=figure; |
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64 | else |
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65 | figure(hfig); |
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66 | end |
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67 | haxes=findobj(hfig,'Type','axes'); |
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68 | if ~isempty(haxes) |
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69 | axes(haxes) |
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70 | end |
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71 | x_vec=linspace(dfreq,freq_max,np_freq); |
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72 | plot(x_vec',spec) |
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73 | xlabel('frequency (Hz)') |
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74 | ylabel('spectral intensity') |
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75 | grid on |
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76 | |
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77 | % |
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78 | % |
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79 | % np=length(funcinterp); |
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80 | % funcinterp=funcinterp-sum(funcinterp)/np; %substract mean |
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81 | % fourier=fft(funcinterp);%take fft (complex) |
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82 | % spec=abs(fourier).*abs(fourier);% take sqare of the modulus |
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83 | % spec=spec([1:floor(np/2)]);%keep only the first half (the other is symmetric) |
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84 | % eval(['Field.' varname '=spec;']) |
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85 | % Field |
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86 | % % dfreq=1/(time(end)-time(1));%frequency interval |
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87 | % % freq=[0:dfreq:(floor(np/2)-1)*dfreq]; |
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88 | % % figure(1) |
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89 | % % hold on |
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90 | % % plot(freq,spec) |
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91 | % % xlabel('frequency (Hz)') |
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92 | % % ylabel('spectral intensity') |
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93 | % % title(['spectrum of' fields]); |
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94 | % % grid on |
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95 | % |
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