Nested For Loop Help

Question

Jacey Allen 2019-3-18

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/450819-nested-for-loop-help

评论： Star Strider 2019-3-18

I am trying to graph 9 plots. 3 for each altitude, with given T0 and P0, for Mach (M0) against F,spillage, and N_corr4. I had to find an M0 for each altitude(i), each mdotf(j), and each operating line that has the given parameters from the mdot_corr2 to N_corr2 section of the code(k). I'm pretty sure I have a good concept for finding the needed values to come up with my plots, but I am not confident in how I indexed the variables, used fsolve with the indexing, nested the for loops, and how I made the plots inside of the for loops. When I ran this code, it took forever and gave me over 400 plots when I stopped it. Any help would be much appreciated!!

alt=[0,5000,10000];
T0=[288,255.65,223.26];
P0=[101325,54019.9,26500];
mdotf=[mdotfR*.2:mdotfR*.2:mdotfR*3];
mdot_corr2=[mdot_corr21,mdot_corr22,mdot_corr23,mdot_corr24,mdot_corr25,mdot_corr2R,mdot_corr26,mdot_corr27];
total_temp_ratio_42=[total_temp_ratio_42_1,total_temp_ratio_42_2,total_temp_ratio_42_3,total_temp_ratio_42_4,total_temp_ratio_42_5,total_temp_ratio_42_R,total_temp_ratio_42_6,total_temp_ratio_42_7];
tc=[tc1,tc2,tc3,tc4,tc5,tcR,tc6,tc7];
pc=[pc1,pc2,pc3,pc4,pc5,pcR,pc6,pc7];
tt=[tt1,tt2,tt3,tt4,tt5,ttR,tt6,tt7];
pt=[pt1,pt2,pt3,pt4,pt5,ptR,pt6,pt7];
N_corr2=[N_corr21,N_corr22,N_corr23,N_corr24,N_corr25,N_corr2R,N_corr26,N_corr27];
for i=1:3
    for j=1:15
        for k=1:8
            fun3=@(M0) (((pdR*P0(i)*(1+((g-1)/2)*M0^2)^(g/(g-1)))/Pstp)*sqrt(Tstp)*mdot_corr2(k)*cp*sqrt((T0(i)*(1+((g-1)/2)*M0^2)))*(total_temp_ratio_42(k)-tc(k))-mdotf(j)*h);
            M0_0=.5;
            M0(i,j,k)=fsolve(fun3,M0_0);
            %Station 0%
            u0(i,j,k)=M0(i,j,k)*sqrt(g*R*T0(i));
            rho0(i)=P0(i)/(R*T0(i));
            tr(i,j,k)=1+((g-1)/2)*M0(i,j,k)^2;
            pr(i,j,k)=tr(i,j,k)^(g/(g-1));
            %Station 2%
            Pt2(i,j,k)=pdR*P0(i)*(1+((g-1)/2)*M0(i,j,k)^2)^(g/(g-1));
            Tt2(i,j,k)=T0(i)*(1+((g-1)/2)*M0(i,j,k)^2);
            %Station 3%
            Tt3(i,j,k)=Tt2(i,j,k)*tc(k);
            Pt3(i,j,k)=Pt2(i,j,k)*pc(k);
            %Station 4%
            Tt4(i,j,k)=total_temp_ratio_42(k)*Tt2(i,j,k);
            Pt4(i,j,k)=Pt3(i,j,k)*pbR;
            %Station 5%
            Tt5(i,j,k)=Tt4(i,j,k)*tt(k);
            Pt5(i,j,k)=Pt4(i,j,k)*pt(k);
            %Station 8%
            Tt8(i,j,k)=Tt5(i,j,k);
            Pt8(i,j,k)=Pt5(i,j,k);
            T8(i,j,k)=Tt8(i,j,k)/(1+((g-1)/2)*M8^2);
            P8(i,j,k)=Pt8(i,j,k)/((1+((g-1)/2)*M8^2)^(g/(g-1)));
            rho8(i,j,k)=P8(i,j,k)/(R*T8(i,j,k));
            u8(i,j,k)=M8*sqrt(g*R*T8(i,j,k));
            %Performance%
            f(i,j,k)=(tr(i,j,k)*(total_temp_ratio_42(k)-tc(k)))/(h/(cp*T0(i)));
            mdot(i,j,k)=mdotf(j)/f(i,j,k);
            A0(i,j,k)=mdot(i,j,k)/(rho0(i)*u0(i,j,k));
            spillage(i,j,k)=(rho0(i)*u0(i,j,k)*A1R)-(rho0(i)*u0(i,j,k)*A0(i,j,k));
            A8(i,j,k)=mdot(i,j,k)/(rho8(i,j,k)*u8(i,j,k));
            F(i,j,k)=mdot(i,j,k)*(u8(i,j,k)-u0(i,j,k))+(P8(i,j,k)-P0(i))*A8(i,j,k);
            mdot_corr4(i,j,k)=mdot(i,j,k)*(sqrt(Tt4(i,j,k)/Tstp)/(Pt4(i,j,k)/Pstp));
            turb_xaxis(k)=mdot_corr2(k)*N_corr2(k)*(1/(pc(k)*pbR));
            N_corr4(i,j,k)=turb_xaxis(k)/mdot_corr4(i,j,k);
            
            if pc(k)>15.6
                break
            end
            if Tt4(i,j,k)>2200
                break
            end
            if N_corr2(k)>25000
                break
            end
            if M0(i,j,k)<0 && M0(i,j,k)>2.4
                break
            end
            
            figure
            hold on
            scatter(M0(i,j,k),F(i,j,k))
            hold off
            figure
            hold on
            scatter(M0(i,j,k),spillage(i,j,k))
            hold off
            figure
            hold on
            scatter(M0(i,j,k),N_corr4(i,j,k))
            hold off
            
        end
    end
end

2 个评论
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dpb 2019-3-18

Overload!!!!

We don't have your data, don't "know nuthnk!" about your problem space so have essentially "no chance!" to fix your problem as given.

As a start, I would recommend you compute what data you need and get it organized so you can retrieve that which needs to be plotted together by addressing it either as indices in arrays or by variables in a table or other data structure.

Once you have that, decide what is to be plotted on a given figure and arrange to create that number of figures and pull the necessary data for each...

Trying to do everything in one set of deeply nested loops is just too much complexity to keep straight.

Stephen23 2019-3-18

编辑：Stephen23 2019-3-18

在 MATLAB Online 中打开

Start by moving your scatter after the two inner loops, and preallocate the plotted data arrays before the two inner loops (pseudocode):

for ii = 1:3
    A = nan(...); % preallocate
    B = nan(...); % preallocate
    C = nan(...); % preallocate
    ...
    for jj = 1:5
        for kk = 1:8
             .... your code
        end
    end
    figure()
    subplot(...)
    scatter(A,...)
    subplot(...)
    scatter(B,...)
    subplot(...)
    scatter(C,...)
end

That will give you exactly nine plots in three figures.

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Answer 1

Star Strider 2019-3-18

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/450819-nested-for-loop-help#answer_366010

在 MATLAB Online 中打开

If you only want plots for the three ‘i’ indices, I would remove the scatter calls from the innermost loop, change them to plot calls, and put them in the outermost loop instead:

for i=1:3
    for j=1:15
        for k=1:8
            ... CODE ...
        end
    end
    figure
    hold on
    plot(squeeze(M0(i,:,:)),squeeze(F(i,:,:)))
    hold off
    figure
    hold on
    plot(squeeze(M0(i,:,:)),squeeze(spillage(i,:,:)))
    hold off
    figure
    hold on
    plot(squeeze(M0(i,:,:)),squeeze(N_corr4(i,:,:)))
    hold off
end

The scatter function wants only vectors, however plot will accept 2D matrices. The squeeze function eliminates the first (‘i’ dimension), so plot will not throw an error on matrices with dimensions greater than 2.

NOTE — This is UNTESTED CODE. I can’t run your code to check this, however some experiments I did suggest that this will work.

Experiment to get the result you want.