How do I fix this error "In an assignment A(:) = B, the number of elements in A and B must be the same."?

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Alec Carruthers 2018-4-5

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https://ww2.mathworks.cn/matlabcentral/answers/392953-how-do-i-fix-this-error-in-an-assignment-a-b-the-number-of-elements-in-a-and-b-must-be-the-s

回答： Star Strider 2018-4-5

clc; clear;

%Design Mission PAX = 250;

Cargo = 8000; Range = 7000; %N. Miles DRatio = .9524988; PRatio = .23590495; M = .85; Vapp = 145; %Knots TOFL = 10500; %Feet a = 576.4592054; % Speed of Sound at 35,000 ft, KNOTS

%%%%%%% Values Changed Manually %%%%%%%%% Abreast = 8; % Tested 4 - 8 N_aisle = 1; % Tested 1 & 2 Sweep = 25; % Degrees, Tested: 25, 30, 35, 40 AR = 8; % Tested: 6-9 Airfoil = 1; % Supercritical = 1, Conventional = 2.

% Assuming a Cl value so need a for loop. CL=[.45:.01:.6]; n = length(CL); DelM = zeros(1,n);

syms x for i= 1:n

if Airfoil == 1
    DelM(i) = vpasolve((CL(i)==((-2*10^9)*x^6)-((1*10^8)*x^5)-((2*10^6)*x^4)-((2632.1*x^3)+124.37*x^2)-(5.8637*x)+.5475),x,[-.01 .015]);
end
if Airfoil == 2
    DelM(i) = vpasolve(CL(i)==(-5.1087*x^2)-(2.9657*x)+.5509);
end
 NewDelM=double(DelM);
% M_Crit=(M+.004)
end

There should be 1 DelM value for every CL iteration. This is why I put the constraint on vpasolve to only use a certain solution. I am still not sure why I am getting the following error: "In an assignment A(:) = B, the number of elements in A and B must be the same."

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Alec Carruthers 2018-4-5

在 MATLAB Online 中打开

clc; clear;

%Design Mission

PAX = 250;

Cargo = 8000;

Range = 7000; %N. Miles

DRatio = .9524988;

PRatio = .23590495;

M = .85;

Vapp = 145; %Knots

TOFL = 10500; %Feet

a = 576.4592054; % Speed of Sound at 35,000 ft, KNOTS

%%%%%%% Values Changed Manually %%%%%%%%%

Abreast = 8; % Tested 4 - 8

N_aisle = 1; % Tested 1 & 2

Sweep = 25; % Degrees, Tested: 25, 30, 35, 40

AR = 8; % Tested: 6-9

Airfoil = 1; % Supercritical = 1, Conventional = 2.

% Assuming a Cl value so need a for loop. CL=[.45:.01:.6]; n = length(CL); DelM = zeros(1,n);

syms x for i= 1:n

if Airfoil == 1
    DelM(i) = vpasolve((CL(i)==((-2*10^9)*x^6)-((1*10^8)*x^5)-((2*10^6)*x^4)-((2632.1*x^3)+124.37*x^2)-(5.8637*x)+.5475),x,[-.01 .015]);
end
if Airfoil == 2
    DelM(i) = vpasolve(CL(i)==(-5.1087*x^2)-(2.9657*x)+.5509);
end
 NewDelM=double(DelM);
% M_Crit=(M+.004)
end