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Last seen: 1 day 前 |  自 2017 起处于活动状态

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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...

1 day 前 | 1 个回答 | 0

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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 ...

20 days 前 | 1 个回答 | 0

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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...

29 days 前 | 2 个回答 | 0

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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...

1 month 前 | 2 个回答 | 0

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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...

1 month 前 | 1 个回答 | 0

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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 ...

2 months 前 | 1 个回答 | 0

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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...

2 months 前 | 1 个回答 | 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...

2 months 前 | 1 个回答 | 0

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提问


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 前 | 3 个回答 | 0

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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 前 | 1 个回答 | 0

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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...

3 years 前 | 1 个回答 | 0

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Filled figures, saved as eps or pdf, now have weird lines when zoomed in, while png files do not,
Hi, My filled figures, e.g. ellipses, using either the fill() or patch functions, and saved as eps or pdf files, now have weir...

3 years 前 | 1 个回答 | 0

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提问


Choosing more stringent values for RelTol and AbsTol in ode45, for smooth functions such as sin(t) or cos(t), does not change the numerical solutions,
Hi, I'm playing with the RelTol and AbsTol options for the ode45 solver, choosing more stringent values such as 1e-10 for bo...

4 years 前 | 0 个回答 | 0

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How does choosing more stringent RelTol and AbsTol values in ode45 compare with choosing finer tspan integration time-steps?
Hi, So I modified my ode45 error tolerances, both RelTol and AbsTol, to be at 1e-10. 1e-14 or so seems to be the most strin...

4 years 前 | 1 个回答 | 0

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How can I get Matlab's Command Window to output the entire column vector of solutions?
Hi, Matlab's Command Window seems to cut off a long column vector of solutions. What is the default limit set to, and h...

4 years 前 | 1 个回答 | 0

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How to store all of the converged roots found by Matlab's fsolve algorithm?
Hi, I'm practicing with Matlab's fsolve function, and am calling it with a few nested for loops that provide fsolve with var...

4 years 前 | 1 个回答 | 0

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What is it called when I specify a vector output of solutions from, say, fsolve?
Hi, I have a simple question -- just a matter of lingo, I think: The fsolve algorithm gives all these outputs when it arr...

4 years 前 | 1 个回答 | 0

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How can I improve this really slow code, which consists of several nested for loops?
Hi, So I've written these nested for loops, but it takes a very long time to execute this code: for T = linspace( 1, 5, 1...

4 years 前 | 1 个回答 | 0

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In nested for-loops, how and where should I set the counting index (indices?) correctly, for doing numerical root-finding using fsolve?
Hi, Let's say I have a function, f, that maps R^3 to R^3, and I want to find its multivariable roots numerically, using fsol...

4 years 前 | 1 个回答 | 0

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What information is conveyed by the different colors in Matlab's contourf( ) data plots?
Hi, Matlab has a contourf( ) function, which I used a little bit last night to plot the level sets of say, Z = f(x,y) = ...

4 years 前 | 1 个回答 | 0

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Inner matrix dimensions must agree error message,
Hi, I'm getting an error message that says inner matrix dimensions must agree, but I checked both matrices and they seem fin...

4 years 前 | 1 个回答 | 0

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Do vector fields mapping R^2 to R^2 have to be coded in separate function files, or can I define anonymous functions for them directly in the script file?
Hi, I've been writing functions from R^2 to R^2, i.e. F( f_1(x,y), f_2(x,y) )= (z_1, z_2), in separate function files, and th...

4 years 前 | 1 个回答 | 0

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What is considered good practice for coding up a function's derivatives, e.g. its Jacobian and Hessian matrices?
Hi, I'm currently practicing numerical root-finding, using simple sets of nonlinear equations and writing my own solvers -- ...

4 years 前 | 1 个回答 | 0

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Debugging Newton's Method code in two variables,
Hi, I wrote a simple code for Newton's Method in two variables but am having some trouble debugging it. Here's the message ...

4 years 前 | 1 个回答 | 0

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How to get Matlab to return answers with ten-digit accuracy?
Hi, Answers returned by Matlab (e.g. from the ode45 solver, or from the wrapTo2Pi function that maps accumulating angles to [0,...

4 years 前 | 2 个回答 | 0

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fsolve handling a composition of functions gives the error, "not enough input arguments"
I'm having some trouble using fsolve on a composition of functions. I've tried fsolve on a much simpler composition, and it wor...

4 years 前 | 2 个回答 | 0

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提问


How can I create elliptical-shaped markers?
I have two columns of data [X Y] that I would like to plot with elliptical-shaped markers.

7 years 前 | 1 个回答 | 0

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How accurate is the numerical integrator, cumtrapz?
How accurate is the numerical integrator, cumtrapz?

7 years 前 | 1 个回答 | 0

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how can I rotate the ellipses based on the orientation angle of (x_i,y_i)?
I would like to rotate the ellipses to show the orientation, theta, of the centered data points.

7 years 前 | 2 个回答 | 0

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how can I center my data
I would like to draw an ellipse, and then center my data points on these ellipses.

7 years 前 | 1 个回答 | 0

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