I get this message(Attempted to access F(5); index out of bounds because numel(F)=4.) when I run the code below..

Question

Nora Fattah Ahmed 2024-1-28

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2075266-i-get-this-message-attempted-to-access-f-5-index-out-of-bounds-because-numel-f-4-when-i-run-the

编辑： Nora Fattah Ahmed 2024-1-28

refpaper3
Index exceeds the number of array elements. Index must not exceed 4.

Error in solution>refpaper3/fsode (line 68)
        F(5)=(-1/(M1*M2))*((2*M2*Omega*Y(5))+(Pr*Y(1)*Y(5))+(Du*((M1*F(7))+(2*Omega*Y(7))))+(Pr*Ec*M1*(Y(3))^2));

Error in bvparguments (line 96)
testODE = ode(x1,y1,odeExtras{:});

Error in bvp4c (line 119)
    bvparguments(solver_name,ode,bc,solinit,options,varargin);

Error in solution>refpaper3 (line 40)
    sol = bvp4c(@fsode,@fsbc,solinit,options);
function refpaper3
format long
%% ------------------------------------------------------------------------
% Parameters
%--------------------------------------------------------------------------
NP=200; %the number of meshpoints
eta_infty =15;
%% ------------------------------------------------------------------------
for i=1:4
    A=0.1*[0 2 4 6];  
    Omega=A(i);
    % eps=0.1;   %A=0.1*[2 4 6 8 9];       %Medium porosity
    % gamma=3;    %A=[2 3 4 5 6];
    % M=0.6;         %A=[2 3 4 5 6];           %magnetic field parameter
    % Omega=3;     %A=[4 5 6 7 8];           %cylinder curvature parameter  
    Alpha=45;                              %curvature angel
    P=0.2;         %A=[3 4 5 6 7];           %porous medium parameter
    Gr=0.2;      %A=[0 2 3 4 5];           %themal Grashof number
    Gm=0.2;                                %mass Grashof number
    Rd=0.1;        %A=0.1*[0 1 3 5 7];       %Radiation parameter
    Ec=0.1;                               %Eckert number
    Du=0.5;      %A=0.1*[1 2 3 4 5];       %Defour number     
    Sr=0.2;      %A=0.1*[2 3 4 5 6];       %Soret number   
    Pr=1.0;     %for water7.56            %prentdl number
    Sc=5;        %A=[5 7 9 11 13];         %Schmidt number
    Bi1=0.2;                       
    Bi2=0.2;
    % QM=0.1;                               %mass flux 
    % QH=0.24;                               %heat flux 
    %--------------------------------------------------------------------------
    %  Solve the problem
    %--------------------------------------------------------------------------
    int=ones(1,7); %We have 7 variables
    int=0.*int;
    % int=[0 0 -0.003 -0.35 0 0 -0.05];
    options = [];
    solinit = bvpinit(linspace(0,eta_infty,NP),int);
    sol = bvp4c(@fsode,@fsbc,solinit,options);
    eta = sol.x; %this is eta
    f = sol.y;   %These are the dependenat variables
    FF=f(1,:);
    DF=f(2,:);
    DDF(i)=-f(3,1);
    TH=f(4,:);
    DTH(i)=f(5,1);
    Fi =f(6,:);
    DFi=f(7,1);
    HH(i)= -2*DTH(i);
    RR(i)=Omega;
    
    %QH=(1+xi_2)*gamma+(1/Pr)*(1+((4*Rd)/3))*DTH;
    %% ------------------------------------------------------------------------
    % Plot the results
    %--------------------------------------------------------------------------
end
%% ------------------------------------------------------------------------
% The model equations
%--------------------------------------------------------------------------
    function dfdeta = fsode(eta,Y)
        M1=1+(2*Omega*eta);
        M2=1+(4*Rd/3);
        F(1) = Y(2);
        F(2) = Y(3);
        F(3) =(-1/M1)*((2*Omega*Y(3))+(Y(1)*Y(3))+(Y(2)^2)-(P*Y(2))+(((Gr*Y(4))+(Gm*Y(6)))*cosd(Alpha)));
        F(4)=Y(5);
        F(5)=(-1/(M1*M2))*((2*M2*Omega*Y(5))+(Pr*Y(1)*Y(5))+(Du*((M1*F(7))+(2*Omega*Y(7))))+(Pr*Ec*M1*(Y(3))^2));
        F(6)=Y(7);
        F(7)=(-1/M1)*((2*Omega*Y(7))+(Sc*Y(1)*Y(7))+(Sr*((M1*F(5))+(2*Omega*Y(5)))));
        dfdeta = [ F(1)
            F(2)
            F(3)
            F(4)
            F(5)
            F(6)
            F(7)
            ];
    end
% --------------------------------------------------------------------------
    function res = fsbc(ya,yb)
        res = [ya(1)         
            ya(2)-1                      
            ya(5)+(Bi1*(1-ya(4)))                   
            ya(7)+(Bi2*(1-ya(6)))                                   
            yb(2)                      
            yb(4)
            yb(6)
            
            ];
    end
end

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Dyuman Joshi 2024-1-28

@Nora Fattah Ahmed, You do not need to use clear, clc, close inside of a function. Remove them.

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Answer 1

Alan Stevens 2024-1-28

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2075266-i-get-this-message-attempted-to-access-f-5-index-out-of-bounds-because-numel-f-4-when-i-run-the#answer_1398556

In fsode you try to use F(7) when calculating F(5), before you have calculated F(7)!

2 个评论
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Dyuman Joshi 2024-1-28

I suspect OP meant to use Y(7) instead of F(7).

Nora Fattah Ahmed 2024-1-28

编辑：Nora Fattah Ahmed 2024-1-28

No, it is F(7), not Y(7). I discovered where the problem was.The last two equations in the system I work on had to be solved together first to obtain the values of F(5) and F(7) because they depend on each other.This is the second time I discover my mistake after sending the question.but thank you so much.It's like brain refreshment..

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