[170] | 1 | % 'FFT': calculate and display spectrum of the field selected in the GUI get_field |
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| 2 | % GUI_input=FFT(hget_field) |
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| 3 | % |
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| 4 | % OUTPUT: |
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| 5 | % GUI_input: option for display in the GUI get_field |
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| 6 | % |
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| 7 | %INPUT: |
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| 8 | % hget_field: handles of the GUI get_field |
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| 9 | % |
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| 10 | |
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[36] | 11 | function GUI_input=FFT(hget_field) |
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| 12 | global spec x_vec |
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| 13 | %requests for the visibility of input windows in the GUI series (activated directly by the selection in the menu ACTION) |
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| 14 | if ~exist('hget_field','var') |
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[89] | 15 | GUI_input={'check_1Dplot'}; |
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[36] | 16 | return %exit the function |
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| 17 | end |
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[93] | 18 | GUI_input=[]; |
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[36] | 19 | %initiation |
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| 20 | hhget_field=guidata(hget_field); |
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| 21 | abscissa_list=get(hhget_field.abscissa,'String'); |
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| 22 | val=get(hhget_field.abscissa,'Value'); |
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| 23 | val=val(1); |
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| 24 | abscissa_name=abscissa_list{val}; |
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| 25 | ordinate_list=get(hhget_field.ordinate,'String'); |
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| 26 | val=get(hhget_field.ordinate,'Value'); |
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| 27 | val=val(1); %take only the first variable in the list |
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| 28 | |
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| 29 | ordinate_name=ordinate_list{val}; |
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| 30 | |
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| 31 | [Field,errormsg]=read_get_field(hget_field); |
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| 32 | if ~isempty(errormsg) |
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| 33 | msgbox_uvmat('ERROR',['error in get_field/FFT input:' errormsg]) |
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| 34 | return |
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| 35 | end |
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| 36 | |
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| 37 | % get variable |
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| 38 | eval(['Var= Field.' ordinate_name ';']); |
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[170] | 39 | np=size(Var); |
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[36] | 40 | np_freq=floor(np(1)/2); |
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| 41 | dx=1;%default |
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| 42 | dfreq=1/np(1);%default frequency interval (abscissa= array index) |
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[93] | 43 | sum_data=sum(Var,2); |
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[36] | 44 | if ~isequal(abscissa_name,'') |
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| 45 | eval(['Coord_x= Field.' abscissa_name ';']); |
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[93] | 46 | ind_select=find(~isinf(Coord_x)&~isnan(sum_data));%detect infinite values |
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[36] | 47 | Coord_x=Coord_x(ind_select); |
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| 48 | Var=Var(ind_select,:); |
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| 49 | diff_x=diff(Coord_x); |
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| 50 | dx=min(diff_x); |
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| 51 | %interpolate on a regular abscissa interval if needed |
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| 52 | if (max(diff_x)-dx)> 0.001*dx || numel(ind_select)<np(1) |
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| 53 | xequ=Coord_x(1):dx:Coord_x(end);%equal time spacingdx= |
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| 54 | Var=interp1(Coord_x,Var,xequ); %interpolated func |
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| 55 | np=size(Var); |
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| 56 | end |
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| 57 | % funcinterp=interp1(time,func,timeq); %interpolated func |
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| 58 | dfreq=1/(Coord_x(end)-Coord_x(1));%frequency interval |
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| 59 | end |
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| 60 | freq_max=1/(2*dx); |
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| 61 | Var=Var-ones(np(1),1)*mean(Var,1); %substract mean value |
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| 62 | fourier=fft(Var);%take fft (complex) |
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| 63 | spec=abs(fourier).*abs(fourier);% take square of the modulus |
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| 64 | spec=spec(1:np_freq,:);%keep only the first half (the other is symmetric) |
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| 65 | |
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| 66 | %plot |
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| 67 | list_fig=get(hhget_field.list_fig,'String'); |
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| 68 | val=get(hhget_field.list_fig,'Value'); |
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[170] | 69 | hfig=str2num(list_fig{val});% chosen figure number from tyhe GUI |
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[36] | 70 | if isempty(hfig) |
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| 71 | hfig=figure; |
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| 72 | else |
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| 73 | figure(hfig); |
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| 74 | end |
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| 75 | haxes=findobj(hfig,'Type','axes'); |
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| 76 | if ~isempty(haxes) |
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| 77 | axes(haxes) |
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| 78 | end |
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| 79 | x_vec=linspace(dfreq,freq_max,np_freq); |
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| 80 | plot(x_vec',spec) |
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| 81 | xlabel('frequency (Hz)') |
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| 82 | ylabel('spectral intensity') |
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| 83 | grid on |
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| 84 | |
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| 85 | % |
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| 86 | % |
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| 87 | % np=length(funcinterp); |
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| 88 | % funcinterp=funcinterp-sum(funcinterp)/np; %substract mean |
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| 89 | % fourier=fft(funcinterp);%take fft (complex) |
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| 90 | % spec=abs(fourier).*abs(fourier);% take sqare of the modulus |
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| 91 | % spec=spec([1:floor(np/2)]);%keep only the first half (the other is symmetric) |
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| 92 | % eval(['Field.' varname '=spec;']) |
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| 93 | % Field |
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| 94 | % % dfreq=1/(time(end)-time(1));%frequency interval |
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| 95 | % % freq=[0:dfreq:(floor(np/2)-1)*dfreq]; |
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| 96 | % % figure(1) |
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| 97 | % % hold on |
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| 98 | % % plot(freq,spec) |
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| 99 | % % xlabel('frequency (Hz)') |
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| 100 | % % ylabel('spectral intensity') |
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| 101 | % % title(['spectrum of' fields]); |
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| 102 | % % grid on |
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| 103 | % |
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