MATLAB: How to eliminate the error

b.luong@fogale.findmycountryfuzzy

>> %input, generating 13 points on curve >> x=[-50 -41.2 -34.2 -27.13 -18.05 -6.94 -1.93*10.^(-33) 12.31 22.5 32.69 41.86 46.9 51.02];

>> y=[-5 -1.66 0.36 2.04 3.64 4.77 5 4.76 4.09 2.99 1.64 0.74 -0.0698];

>> %spline that interpolates (x,y) >> s=spline(x,y)

s =

      form: 'pp'
    breaks: [1x13 double]
     coefs: [12x4 double]
    pieces: 12
     order: 4
       dim: 1

>> %first derivative,pp form

>> s1=s; >> s1.order=s.order-1

s1 =

      form: 'pp'
    breaks: [1x13 double]
     coefs: [12x4 double]
    pieces: 12
     order: 3
       dim: 1

>> s1.coefs=bsxfun(@time,s1.coefs(:,1:end-1),s1.order:-1:1) ??? Error using ==> bsxfun Undefined function 'time' for input arguments of type 'double'.

what does this error means and how to solve it…??

Can any one help me.. in going furthest to find curvature

Best Answer

@time ===> @times
s1.coefs=bsxfun(@times,s1.coefs(:,1:end-1),s1.order:-1:1)

Related Solutions

MATLAB: How to automatically assign colors to data that’s being dynamically plotted and recycle the colors if there’s more data that needs to be plotted

So I think this might be what you're looking for. I commented out the 'i' redefinition at the very bottom and added 'figure' but to answer the coloring question I recommend using the mod (for modulus) command. If you specify

color{mod(i-1,4)+1}

the values, for i=1:8 for example, will go:

color{1}
color{2}
color{3}
color{4}
color{1}
color{2}
color{3}
color{4}

and the pattern will keep repeating for varying 'i' definitions. Here is the modified code:

AOI=[0 0 0 0 0 0 3 3 3 3 3 3 3 3 3 3 3 3 4 4 4 4 4 4 4 4 4 4 4 4 4 3 3 3 3 3 3 3 3 3 5 5 5 5 5 5 5 5 5 5 6 6 6 6 6 6 6 8 8 8 8 8 8];
row1=[35 35 35 35 36 36.5 37 35 37 35 36 37 36 35 37 34 34 35 36 36 36 37 37 37 38 38 34 34 35 35 35 35 35 35 35 35 35 36 36.5 37 35 37 36 35 37 34 34 35 36 36 36 37 37 37 38 38 34 34 35 35 35 35 35];
col1= [56 57 57 58 56 57 56 56 56 57 45 45 46 46 46 44 45 45 46 46 47 47 48 48 46 46 45 46 45 46 47 56 56 57 57 58 56 57 56 56 56 57 45 45 46 46 46 44 45 45 46 46 47 47 48 48 46 46 45 46 45 46 47];
row2=[35 35 35 35 36 36.5 37 35 37 35 36 37 36 35 37 34 34 35 36 36 36 37 37 37 38 38 34 34 35 35 35 35 35 35 35 35 35 36 36.5 37 35 37 36 35 37 34 34 35 36 36 36 37 37 37 38 38 34 34 35 35 35 35 35];
col2= [56 57 57 58 56 57 56 56 56 57 45 45 46 46 46 44 45 45 46 46 47 47 48 48 46 46 45 46 45 46 47 56 56 57 57 58 56 57 56 56 56 57 45 45 46 46 46 44 45 45 46 46 47 47 48 48 46 46 45 46 45 46 47];
row3=[35 35 35 35 36 36.5 37 35 37 35 36 37 36 35 37 34 34 35 36 36 36 37 37 37 38 38 34 34 35 35 35 35 35 35 35 35 35 36 36.5 37 35 37 36 35 37 34 34 35 36 36 36 37 37 37 38 38 34 34 35 35 35 35 35];
col3= [56 57 57 58 56 57 56 56 56 57 45 45 46 46 46 44 45 45 46 46 47 47 48 48 46 46 45 46 45 46 47 56 56 57 57 58 56 57 56 56 56 57 45 45 46 46 46 44 45 45 46 46 47 47 48 48 46 46 45 46 45 46 47];
row4=[25 25 25 25 26 26.5 27 25 27 25 26 27 26 25 27 24 24 25 26 26 26 27 27 27 28 28 24 24 25 25 25 25 25 25 25 25 25 26 26.5 27 25 27 26 25 27 24 24 25 26 26 26 27 27 27 28 28 24 24 25 25 25 25 25];
col4= [56 57 57 58 56 57 56 56 56 57 45 45 46 46 46 44 45 45 46 46 47 47 48 48 46 46 45 46 45 46 47 56 56 57 57 58 56 57 56 56 56 57 45 45 46 46 46 44 45 45 46 46 47 47 48 48 46 46 45 46 45 46 47];
row5=[35 35 35 35 36 36.5 37 35 37 35 36 37 36 35 37 34 34 35 36 36 36 37 37 37 38 38 34 34 35 35 35 35 35 35 35 35 35 36 36.5 37 35 37 36 35 37 34 34 35 36 36 36 37 37 37 38 38 34 34 35 35 35 35 35];
col5= [66 67 67 68 66 67 66 66 66 67 65 65 66 66 66 64 65 65 66 66 67 67 68 68 66 66 65 66 65 66 67 66 66 67 67 68 66 67 66 66 66 67 65 65 66 66 66 64 65 65 66 66 67 67 68 68 66 66 65 66 65 66 67];
row6=[35 35 35 35 36 36.5 37 35 37 35 36 37 36 35 37 34 34 35 36 36 36 37 37 37 38 38 34 34 35 35 35 35 35 35 35 35 35 36 36.5 37 35 37 36 35 37 34 34 35 36 36 36 37 37 37 38 38 34 34 35 35 35 35 35];
col6= [56 57 57 58 56 57 56 56 56 57 45 45 46 46 46 44 45 45 46 46 47 47 48 48 46 46 45 46 45 46 47 56 56 57 57 58 56 57 56 56 56 57 45 45 46 46 46 44 45 45 46 46 47 47 48 48 46 46 45 46 45 46 47];
row7=[35 35 35 35 36 36.5 37 35 37 35 36 37 36 35 37 34 34 35 36 36 36 37 37 37 38 38 34 34 35 35 35 35 35 35 35 35 35 36 36.5 37 35 37 36 35 37 34 34 35 36 36 36 37 37 37 38 38 34 34 35 35 35 35 35];
col7= [56 57 57 58 56 57 56 56 56 57 45 45 46 46 46 44 45 45 46 46 47 47 48 48 46 46 45 46 45 46 47 56 56 57 57 58 56 57 56 56 56 57 45 45 46 46 46 44 45 45 46 46 47 47 48 48 46 46 45 46 45 46 47];
row8=[2:2:126];
col8= [56 57 57 58 56 57 56 56 56 57 45 45 46 46 46 44 45 45 46 46 47 47 48 48 46 46 45 46 45 46 47 56 56 57 57 58 56 57 56 56 56 57 45 45 46 46 46 44 45 45 46 46 47 47 48 48 46 46 45 46 45 46 47];
coord=[2:2:126];
times=[1:63];
AOI_unique=unique(AOI);
num_AOI=length(AOI_unique);
colors={'r' 'g' 'b' 'c' };
%while num_AOI>length(colors)
figure
hplt=plot(times,coord, 'DisplayName', 'coord\_pos\_sibs\_xfpi');
        hold on
        hleg=legend('-DynamicLegend');
        set(hleg, 'FontSize',10);
        grid on
        datetick('x','HH:MM:SS', 'keeplimits')
        title('Position of SIBS on FPI')
        xlim([min(times), max(times)])
        xlabel('Time (UT)');
        ylabel('Value');
        hold on
for i=1:length(AOI_unique)
    if AOI_unique(i)==1
        %%Plot







        hplt=plot(times, col1, colors{mod(i-1,4)+1}, 'DisplayName', 'column 1');
        hold on
        hplt=plot(times, row1, 'c--', 'DisplayName', 'row 1');
        hold on
        hleg=legend('-DynamicLegend');
        set(hleg, 'FontSize',10);
        grid on
    elseif AOI_unique(i)==2
        %%Plot
        hplt=plot(times, col2, colors{mod(i-1,4)+1}, 'DisplayName', 'column 2');
        hold on
        hplt=plot(times, row2, 'g--', 'DisplayName', 'row 2');
        hold on
        hleg=legend('-DynamicLegend');
        set(hleg, 'FontSize',10);
        grid on
    elseif AOI_unique(i)==3
        %%Plot
        hplt=plot(times, col3, colors{mod(i-1,4)+1}, 'DisplayName', 'column 3');
        hold on
        hplt=plot(times, row3, 'b--', 'DisplayName', 'row 3');
        hold on
        hleg=legend('-DynamicLegend');
        grid on
        elseif AOI_unique(i)==4
        %%Plot
        hplt=plot(times, col4, colors{mod(i-1,4)+1}, 'DisplayName', 'column 4');
        hold on
        hplt=plot(times, row4, 'r--', 'DisplayName', 'row 4');
        hold on
        hleg=legend('-DynamicLegend');
        set(hleg, 'FontSize',10);
        grid on
        elseif AOI_unique(i)==5
        %%Plot
        hpltA=plot(times, col5, colors{mod(i-1,4)+1}, 'DisplayName', 'column 5');
        hold on
        hplt=plot(times, row5, 'c--', 'DisplayName', 'row 5');
        hold on
        hleg=legend('-DynamicLegend');
        set(hleg, 'FontSize',10);
        grid on
        elseif AOI_unique(i)==6
        %%Plot
        hplt=plot(times, col6, colors{mod(i-1,4)+1}, 'DisplayName', 'column 6');
        hold on
        hpltA=plot(times, row6, 'g--', 'DisplayName', 'row 6');
        hold on
        hleg=legend('-DynamicLegend');
        set(hleg, 'FontSize',10);
        grid on
        elseif AOI_unique(i)==7
        %%Plot
        hplt=plot(times, col7, colors{mod(i-1,4)+1}, 'DisplayName', 'column 7');
        hold on
        hplt=plot(times, row7, 'b--', 'DisplayName', 'row 7');
        hold on
        hleg=legend('-DynamicLegend');
        set(hleg, 'FontSize',10);
        grid on
        elseif AOI_unique(i)==8
        %%Plot
        hplt=plot(times, col8, colors{mod(i-1,4)+1}, 'DisplayName', 'column 8');
        hold on
        hplt=plot(times, row8, 'r--', 'DisplayName', 'row 8');
        hold on
        hleg=legend('-DynamicLegend');
        set(hleg, 'FontSize',10);
        grid on
    end
%     i=i+1;
 end

MATLAB: How to get an equation from an already plotted graph in matlab

Just what type of "function" do you seriously expect to get from that?

So 7000 data points with no simple way to describe them, except using an interpolation. This should suffice:

C = get(gca,'children');
spl = pchip(C.XData,C.YData)
spl = 
  struct with fields:
      form: 'pp'
    breaks: [1×7000 double]
     coefs: [6999×4 double]
    pieces: 6999
     order: 4
       dim: 1

It probably won't be worth much though, because there is no "equation" you can simply extract from a spline.

If you insist on an equation, I'd suggest randn() is roughly as good as anything else.

Best Answer

Related Solutions

MATLAB: How to automatically assign colors to data that’s being dynamically plotted and recycle the colors if there’s more data that needs to be plotted

MATLAB: How to get an equation from an already plotted graph in matlab

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