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How can I loop over i and j, to compute the ith row and jth column of the Jacobian matrix, using the central difference method?
Hi there! I'm practicing with this toy problem and want to loop over i and j to compute the ith row and jth column of the Jacob...

2 hours ago | 0 answers | 0

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answers

Question

What do you think of my numerical Jacobian, using the central-difference method?
Hi everyone! Here's my 6x6 numerical Jacobian, using the central-difference method. For now, I've used the same step-size h fo...

1 day ago | 3 answers | 0

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My 6x6 symbolic Jacobian matrix is massive, and matlabFunction( ) is having trouble writing the corresponding numerical function file.
Hi there! I currently have a 6x6 symoblic Jacobian using the Symbolic Math Toolbox. It is massive, when I take a peek at it usi...

3 days ago | 2 answers | 0

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answers

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How should I compute the Jacobian for my equations of motion?
Hi there! I have a set of second-order equations of motion written symbolically in Matlab, put into matrix form using Equations...

5 days ago | 1 answer | 0

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Question

Solving odes with ode45 and then checking fixed points for constant behavior,
Update: I just plotted the differences between the dynamical states and the corresponding initial states, and the differences, f...

20 days ago | 1 answer | 0

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Evaluating stability of fixed points in a system of differential equations,
Hi there! Let's say I have a set of coupled ordinary differential equations for which I have found a certain number of fixed po...

27 days ago | 1 answer | 0

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Best way to plot a surface whose matrix has values of +/- infinity
Hi there! What is the best way to plot a 3D surface whose matrix C = A ./ B contains values of +/- infinity (whenever entries in...

4 months ago | 1 answer | 0

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Question

For 3D surface plots, do you like the command, 'shading interp'?
Hi there! For 3D surface plots, do you like the command, 'shading interp'? When I use it, I notice that the color variation on ...

4 months ago | 1 answer | 0

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Question

How to “color” the first curve moving across x-axis in a 3D surface plot?
Hi there! I’d like to “color” the first curve in my 3D surface plot differently from the colormap colors, say, black, to contras...

4 months ago | 1 answer | 0

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Question

From making 2D line plots to making 3D surface plots: How to preserve my current workflow?
Hi there! Below, I think the explanation, originally a comment by me, is more clear, so I am posting it here as the question. ...

4 months ago | 2 answers | 0

2

answers

Question

Error using surf (line 71) Z must be a matrix, not a scalar or vector.
Hi there! I currently have a tiledLayout plot with six tiles; the tiles are plotted against two variables alpha and beta, and I...

4 months ago | 1 answer | 0

1

answer

Question

Ideas for presenting data vs. two variables,
Hi there! I currently have a beautiful figure that presents data vs. two variables. I went from using Matlab's subplot function...

4 months ago | 1 answer | 0

1

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Question

How to remove extraneous Matlab-generated vertical lines that connect function values at jump discontinuities?
Hi there! I previously asked a similar question but I now have a more focused question to ask, I think: When plotting a functi...

4 months ago | 1 answer | 0

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Question

Can I plot two figures simultaneously but with less data for the second figure?
Hi there! Let's say I want to plot the first figure for theta = linspace(0, 2*pi, 1001), but for the second figure I only want ...

4 months ago | 1 answer | 0

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When plotting functions like 1/sin(x), how can I remove the vertical lines at the points of discontinuity?
Hi there! When I plot functions such as 1/sin(x), there are vertical lines that appear at the points of discontinuity. How can I...

4 months ago | 3 answers | 0

3

answers

Question

Is it possible to plot a vector arrow using quiver( ), then, negate the vector so it points in the opposite direction, but then add arrowhead in original direction?
Hi there! This is somewhat embarassing, but I've been trying this little thing for a while now, so I figured it's a good time ...

4 months ago | 1 answer | 0

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Question

Concerned that matlabFunction( ), when converting from symbolic to numerical, changes the sizes of matrices and vectors,
Hi there! I am currently concerned that the function matlabFunction( ), when converting from symbolic to numerical, changes the...

5 months ago | 2 answers | 0

2

answers

Question

Why does Matlab tell me that my ODE function returns a vector of length 12, while the length of my initial conditions vector is 6?
Hi there! I'm getting an error message from Matlab, telling me that my ODE model returns a vector of length 12, while the lengt...

5 months ago | 0 answers | 0

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answers

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'Matrix dimensions must agree' error, when using the backslash operator to solve Ax = b,
Hi there! I am getting a 'matrix dimensions must agree' error message when using the backslash operator \ to solve Ax = b. I we...

5 months ago | 1 answer | 0

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Question

Deciding when to call a Matlab function: Within my symbolic math code, or within my converted numerical code?
Hi there! I wrote a symbolic math code and used the algebraic solver solve( ) to get the equations that I want. I then converte...

5 months ago | 1 answer | 0

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Question

Writing ODE equations for ode45 to solve;
Hi there! I have a basic question to ask here, regarding writing the first-order equations for ode45 to solve. Let's say I am ...

6 months ago | 1 answer | 0

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Question

ode45 integration issues for some choices of physical parameters,
Hi there! I have a simple, two-dimensional, ode model that solves for the trajectory of a flat plate falling through a fluid fl...

6 months ago | 2 answers | 0

2

answers

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Simple question about creating an anonymous function,
Hi there! Using a Matlab function file, I wrote an ode model model(t, z, p), where p stores all of my physical parameters, suc...

6 months ago | 2 answers | 0

2

answers

Question

How to animate background flow field that an object is moving through?
Hi there! I now have a decent code that solves an ode model of mine, using ode45. It is about a rigid plate falling freely thro...

6 months ago | 1 answer | 0

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Question

How can I run code just once, for multiple intervals of numbers?
Let's say I want to calculate things for alpha ranging from 0 to 2pi. I've written if / else-if statements to do this: alpha ...

7 months ago | 1 answer | 0

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Question

How to loop through values?
Let’s say I have 11 values of beta, evenly-spaced with linspace( ). And let’s say for each value of beta, I want to compute some...

7 months ago | 1 answer | 0

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Only the first if-statement block executes,
Hi there! I wrote an if-statement, followed by an if-else statement, followed by another if-else statement, followed by the end...

7 months ago | 1 answer | 0

1

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Question

Using an anonymous function handle as input into another function handle
Hi there! I have a question that's mostly about syntax: Let's say I write the anonymous function handle (for a program to give ...

1 year ago | 3 answers | 0

3

answers

Question

Writing a system of ODEs for ode45
Hi, I wrote a .m-file that has three second-order differential equations, broken down into six first-order equations. When I r...

1 year ago | 1 answer | 0

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Question

How to put fsolve in a loop, using 2 unknowns?
Hi, I want to write a code that asks fsolve to go through some combinations of guesses and then find all the roots (xdot, yd...

4 years ago | 1 answer | 0

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