I am writing a code for using "fmincon" but it is having some error, Why?

Question

Akshay Pratap Singh 2022-5-13

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1718275-i-am-writing-a-code-for-using-fmincon-but-it-is-having-some-error-why

评论： Akshay Pratap Singh 2022-5-14

I am writing the following code. I am not able to find the error? I am new to MATLAB.

dbstop if error
clear all
clc
format longEng
kv = 0.5; kh = 0.1;
r0 = 5; H = 5;
q = 20; a = 1;
b = 0; gamma = 18.4;
omega = 25; phi = 39*(pi/180);
lambda = kv/kh;
syms x(i)
% fun = @(x)A1 /((lambda*A1)+A2)
L = r0*(sin(x(2))*exp((x(2)-x(1))*tan(phi))-sin(x(1)))
% % % % Rate of work due to soil weight in static condition
f1 = -(1/3)*(1/(9*((tan(phi))^2)+1)*(exp(3*(x(2) - x(1))*tan(phi))*(3*tan(phi)*sin(x(2))-cos(x(2)))-(3*tan(phi)*sin(x(1))-cos(x(1)))))
f2 = -(1/6)*(L/r0)*cos(x(2))*exp(x(2)-x(1))*tan(phi)*(2*sin(x(1))+(L/r0))
f3 = -(1/3)*(H/r0)*(sin(x(1)))^2
W1 = (1-kv)*gamma*omega*((r0)^3)*(f1-f2-f3)
% Rate of work due to strip load
Wqs = -(1-kv)*omega*q*b*(a+(b/2)+r0*sin(x(1)))
% % % % Rate of work due to soil weight with kh
fq1 = -(1/3)*(1/(9*((tan(phi))^2)+1)*(exp(3*(x(2) - x(1))*tan(phi))*(3*tan(phi)*cos(x(2))+sin(x(2)))-(3*tan(phi)*cos(x(1))+sin(x(1)))))
fq2 = -(1/3)*(L/(r0)^2)*cos(x(2))*exp(x(2)-x(1))*tan(phi)*(cos(x(1))-(H/r0))
fq3 = -(1/6)*(H/r0)*sin(x(1))*(2*cos(x(1))-(H/r0))
W1kh = kh*gamma*omega*((r0)^3)*(fq1-fq2-fq3)
% Rate of work due to strip load
Wqskh = -kh*omega*q*b*r0*exp((x(2)-x(1))*tan(phi))*cos(x(2))
% Yield acceleration coefficients (ky)
A1 = gamma*omega*((r0)^3)*(f1-f2-f3) - omega*q*b*(a+(b/2)+r0*sin(x(1)))
A2 = omega*q*b*r0*exp((x(2)-x(1))*tan(phi))*cos(x(2)) - gamma*omega*((r0)^3)*(fq1-fq2-fq3)
fun = @(x)A1 /((lambda*A1)+A2)
lb = [0,0];
ub = [3.14,3.14];
A = [];
b = [];
Aeq = [];
beq = []; 
x0 = [0,0];  
nonlcon = [];
x = fmincon(fun,x0,A,b,Aeq,beq,lb,ub,nonlcon)  

1 个评论
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Matt J 2022-5-13

What error messages (copy/pasted) is it giving you?

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Answer 1

Matt J 2022-5-13

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1718275-i-am-writing-a-code-for-using-fmincon-but-it-is-having-some-error-why#answer_963200

在 MATLAB Online 中打开

Your objective function is not returning numbers. It is returning sym variables, e.g.,

>> fun([0,0])

ans =

(6.7465e+03*sin(x(1)) - 2.7771e+03*cos(x(1)) + 2.7771e+03*exp(2.4294*x(2) - 2.4294*x(1))*(cos(x(2)) - 2.4294*sin(x(2))) + 1.9167e+04*sin(x(1))^2 - 4.6563e+04*exp(x(2) - 1*x(1))*cos(x(2))*(sin(x(1)) + exp(0.8098*x(2) - 0.8098*x(1))*sin(x(2)))*(0.1667*sin(x(1)) - 0.1667*exp(0.8098*x(2) - 0.8098*x(1))*sin(x(2))))/(3.0955e+04*sin(x(1)) - 2.0632e+04*cos(x(1)) + 1.3885e+04*exp(2.4294*x(2) - 2.4294*x(1))*(cos(x(2)) - 2.4294*sin(x(2))) + 2.7771e+03*exp(2.4294*x(2) - 2.4294*x(1))*(2.4294*cos(x(2)) + sin(x(2))) + 9.5833e+04*sin(x(1))^2 - 9.5833e+03*sin(x(1))*(2*cos(x(1)) - 1) - 2.3281e+05*exp(x(2) - 1*x(1))*cos(x(2))*(sin(x(1)) + exp(0.8098*x(2) - 0.8098*x(1))*sin(x(2)))*(0.1667*sin(x(1)) - 0.1667*exp(0.8098*x(2) - 0.8098*x(1))*sin(x(2))) + 4.6563e+04*exp(x(2) - 1*x(1))*cos(x(2))*(cos(x(1)) - 1)*(0.0667*sin(x(1)) - 0.0667*exp(0.8098*x(2) - 0.8098*x(1))*sin(x(2))))

>> whos ans

Name Size Bytes Class Attributes

ans 1x1 8 sym

2 个评论
显示无隐藏无

Matt J 2022-5-13

在 MATLAB Online 中打开

lb = [0,0];
ub = [3.14,3.14];
A = [];
b = [];
Aeq = [];
beq = [];
x0 = [0,0];
nonlcon = [];
x = fmincon(@fun,x0,A,b,Aeq,beq,lb,ub,nonlcon)
Local minimum possible. Constraints satisfied.

fmincon stopped because the size of the current step is less than
the value of the step size tolerance and constraints are 
satisfied to within the value of the constraint tolerance.
x = 1×2
    2.2538    3.1342
function fval = fun(x)
    
    kv = 0.5; kh = 0.1;
    r0 = 5; H = 5;
    q = 20; a = 1;
    b = 0; gamma = 18.4;
    omega = 25; phi = 39*(pi/180);
    
    lambda = kv/kh;
    
    % fun = @(x)
    L = r0*(sin(x(2))*exp((x(2)-x(1))*tan(phi))-sin(x(1)));
    % % % % Rate of work due to soil weight in static condition
    
    f1 = -(1/3)*(1/(9*((tan(phi))^2)+1)*(exp(3*(x(2) - x(1))*tan(phi))*(3*tan(phi)*sin(x(2))-cos(x(2)))-(3*tan(phi)*sin(x(1))-cos(x(1)))));
    f2 = -(1/6)*(L/r0)*cos(x(2))*exp(x(2)-x(1))*tan(phi)*(2*sin(x(1))+(L/r0));
    f3 = -(1/3)*(H/r0)*(sin(x(1)))^2;
    W1 = (1-kv)*gamma*omega*((r0)^3)*(f1-f2-f3);
    % Rate of work due to strip load
    Wqs = -(1-kv)*omega*q*b*(a+(b/2)+r0*sin(x(1)));
    
    
    % % % % Rate of work due to soil weight with kh
    
    fq1 = -(1/3)*(1/(9*((tan(phi))^2)+1)*(exp(3*(x(2) - x(1))*tan(phi))*(3*tan(phi)*cos(x(2))+sin(x(2)))-(3*tan(phi)*cos(x(1))+sin(x(1)))));
    fq2 = -(1/3)*(L/(r0)^2)*cos(x(2))*exp(x(2)-x(1))*tan(phi)*(cos(x(1))-(H/r0));
    fq3 = -(1/6)*(H/r0)*sin(x(1))*(2*cos(x(1))-(H/r0));
    W1kh = kh*gamma*omega*((r0)^3)*(fq1-fq2-fq3);
    % Rate of work due to strip load
    Wqskh = -kh*omega*q*b*r0*exp((x(2)-x(1))*tan(phi))*cos(x(2));
    
    
    % Yield acceleration coefficients (ky)
    A1 = gamma*omega*((r0)^3)*(f1-f2-f3) - omega*q*b*(a+(b/2)+r0*sin(x(1)));
    A2 = omega*q*b*r0*exp((x(2)-x(1))*tan(phi))*cos(x(2)) - gamma*omega*((r0)^3)*(fq1-fq2-fq3);
    
    
    fval = A1 /((lambda*A1)+A2);
    
end