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Tony Cheng


Last seen: 25 days ago |  Active since 2017

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Question


Why the peak values are evidently different under the impulse function to a second order function with zero damping?
Hi there, I am using impulse function to get the impulse response of a second order function where the damping is zero. The co...

27 days ago | 2 answers | 0

2

answers

Answered
solve the pendulum problem using ode15s
Hi Shivam, Many thanks for your nice and great help! I am trying to learn your idea in the codes and compare them with mine. H...

3 months ago | 0

Question


solve the pendulum problem using ode15s
Hi guys, The pendulum problem at https://ww2.mathworks.cn/help/symbolic/solve-differential-algebraic-equations.html?s_tid=...

3 months ago | 1 answer | 0

1

answer

Question


how to correctly use the function "subs"
Hi there, I am using subs to replace some symbols in a symbolic expression Jacobian_mtx_1. The symbols that I want to be repla...

4 months ago | 1 answer | 0

1

answer

Question


Jacobian matrix in ode15s
Hi everyone, I am using ode15s to solve a set of stiff odes and the final model is developed in the form of where M(t,y) is...

4 months ago | 1 answer | 0

1

answer

Question


how to format the codes to compute the differential-algebraic equations using ode15s?
Hi guys, I’m trying to use ode15s to solve the dynamic model of a mechanical system in the form of where M is the mass mat...

8 months ago | 1 answer | 0

1

answer

Question


Can ode45 solve differential-algebraic equations?
Hey everyone, Here I just want to ask as the titile shows, can ode45 solve differential-algebraic equations? the differenti...

9 months ago | 1 answer | 0

1

answer

Question


the mass matrix and Jacobian matrix in ode15s
Hi there, I have a set of odes in the form where M and K are n*n matrixes q is a n*1 vector containing the generalised coord...

1 year ago | 3 answers | 2

3

answers

Answered
build an augmented PID control model for a DC servo motor in Simulink
Hi Sam, thx for providing the 2 choices. the term augmented means the actuating torques of a motor for a predefined trajectory a...

1 year ago | 0

Question


build an augmented PID control model for a DC servo motor in Simulink
Hi there, I am going to build an augmented PID control model for a DC servo motor in Simulink. The state-space model of the DC...

1 year ago | 2 answers | 1

2

answers

Question


how to determine the arithematic operations in a code?
Hi there, I want to know: are there any commands in Matlab that can offer us the number of arithematic operations in a code? ...

2 years ago | 1 answer | 0

1

answer

Question


the length of the time span in ode45
Hi there, I am using ode45 to solve a set of ODEs. Here I want to ask, if the length of the time span is relevant to the accur...

3 years ago | 2 answers | 0

2

answers

Question


define a jacobian matrix in odeset for ode15s
Hi guys, I am using ode15s to solve my ODEs. It is said that in odeset ( https://au.mathworks.com/help/matlab/ref/odeset.ht...

5 years ago | 0 answers | 0

0

answers

Question


partial differentating a matrix by a vector
Hi guys, I want to comute , where M is a symbolic matrix , and A is a symbolic vector. Are there any commands in Matl...

5 years ago | 1 answer | 0

1

answer

Question


Substitution of initial numerical values before odefunction
Hi guys, I am using ode45 to solve a system of ODEs. According to the syntax of ode45, the system is formatted into the form of...

5 years ago | 1 answer | 0

1

answer

Question


what functionalDerivative returns is a 1*1 symfun, not a vector
Hi guys, I am trying the codes syms u(x) v(x) H = u^2*diff(v,x)+v*diff(u,x,x); D = functionalDerivative(H,[u v]) at http...

5 years ago | 1 answer | 0

1

answer

Question


Internal error with symbolic engine. Quit and restart MATLAB.
Hi guys, I am using symbolic math toolbox in Matlab 2018b in Win10 64-bit. The problem is Error mupadmex Internal error...

5 years ago | 0 answers | 0

0

answers

Question


Divide large size matrixes, multiply the small matrixes and sum the results together.
I divided two m x n matrixes A and B into several equal i x j matrices using mat2cell, respectively, and then I want to multipl...

5 years ago | 1 answer | 0

1

answer

Question


Why the seond arugment in the command jacobian is not a vector of variables?
Hi guys, I am using the code Jacobian in Matlab to symbolically compute the Jacobian matrix for two vectors-A and B. These two ...

5 years ago | 1 answer | 0

1

answer

Question


Define a 100 * 100 symbolic matrix whose elements are the function of a symbolic variable t
Hi guys, I want to define a symbolic matrix whose size is 100 * 100. All of the elements inside the matrix are all functions ...

5 years ago | 0 answers | 0

0

answers

Answered
Differentiate a 5*5 symbolic matrix by a 5*1 symbolic vector
diff can be used to differentiate a scalar or vector by a scalar, but not differentiate a matrix by a vector.

6 years ago | 0

Answered
How can i differentiate a matrix by vector??
maybe you can differentiate each column of the matrix by the vector, then assemble the results together as a new matrix.

6 years ago | 0

Question


Differentiate a 5*5 symbolic matrix by a 5*1 symbolic vector
Hi there, Here I have a symbolic matrix A with a size of 5*5. The elements inside is composed of 5 symbolic variables , i.e....

6 years ago | 3 answers | 0

3

answers

Question


Why the numerical values for function handle from matlabFunction should be written one by one?
Hi guys, I am now using matlabFunction for change a symbolic expression into a funtion handle. I find a question like this:...

6 years ago | 1 answer | 0

1

answer

Question


Can Pareto show like an envelope?
Hi guys, I am using gamultiobj to optimize six objective functions together. Because there are six objectives, the obtaine...

7 years ago | 1 answer | 0

1

answer

Question


Select a most suitable solution at the Pareto front obtained from gamultiobj
Hi guys, gamultiobj can generate non-dominated optimal solutions at the Pareto front. As there are so many equally optim...

8 years ago | 0 answers | 0

0

answers

Question


How to reduce the number shown on the Y axis?
<</matlabcentral/answers/uploaded_files/69004/%E6%8D%95%E8%8E%B7.JPG>> Hi guys, We can see that 0 , 20 , 40 , 60 and 80, t...

8 years ago | 1 answer | 0

1

answer

Question


gamultiobj's options
Hi guys, I am using a PC with 2014b and run the MOGA files. Now two questions appear: The first is: The option set for ...

8 years ago | 1 answer | 0

1

answer

Question


gamultiobj--Too many input arguments.
Hi guys, I am using gamultiobj to optimize three aims at the same time. The parameters including the aim function, the lin...

8 years ago | 1 answer | 0

1

answer