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Second time derivative of ODE45 solution looks bumpy
t=[0 5]; initz=[0; 0]; [t,z]=ode15s(@f3, t, initz, odeset('RelTol',1e-12,'AbsTol',1e-12)); for i=1:numel(t) dz = f3(t(i),z...

etwa 3 Jahre vor | 0

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How to plot the first derivative of solution?
Piecewise1111copy() function Piecewise1111copy x1=1; u=3; teta=zeros(3,1); teta(1)=0; for i=1:3 teta(i+1)=2*i; end ...

etwa 3 Jahre vor | 0

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How can I fit the parameters using mle with a self-defined function?
Works for me (see above).

etwa 3 Jahre vor | 1

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Error in my MATLAB code
Explicitly listing the sizes of the matrices involved (see above), I come to the conclusion that yd(t) must be a 4x1 column vect...

etwa 3 Jahre vor | 1

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Solving equations with parameters and then inputting different values
Try a solution with c, k, m, x0 and v0 being symbolic variables. Then you only need to "subs" the numerical values for the para...

etwa 3 Jahre vor | 0

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How i can evaluate characteristic function for a random normal vector
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % ChF of X(w) K-dimensional normal(MU,SIGMA) % % X real stochas...

etwa 3 Jahre vor | 0

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Fsolve produces comlex numbers
The usual reasons why solvers like "fsolve" produce complex numbers are: you take the square-root of a negative number (sqrt(x)...

etwa 3 Jahre vor | 0

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When I run my code, I keep getting this error: "Undefined function or variable 'y'."
syms t y(t) syms s real m = 0.05; Dy = diff(y,t); D2y = diff(y,t,2); D3y = diff(y,t,3); eqn = D3y -( -3/m*D2y + 1/m^2*(1-...

etwa 3 Jahre vor | 0

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How can we define the initial conditions u0 at time t+1 as a vector that is equal to the previous initial conditions u0 at time t?
In order to proceed, I need to assign the initial conditions u0 at time t+1 to be equal to the previous initial conditions u0 at...

etwa 3 Jahre vor | 0

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Hi guys, my code doesn't run i couldn't debug this, could you anyone help me?
When you call "calculate_G11_imag", "f "has size 1x2 and "gamma" has size 1x3. Thus f .* gamma is not defined and sum(f .* gamma...

etwa 3 Jahre vor | 0

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Warning: Imaginary parts of complex X and/or Y arguments ignored. > In Finalv3test (line 19) Warning: Imaginary parts of complex X and/or Y arguments ignored. > In Finalv3t
(abs(VGSoff) / VP) is negative, thus (abs(VGSoff) / VP)^sqrt(2) produces complex numbers. Thus ID1 and ID2 are complex-va...

etwa 3 Jahre vor | 0

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Discrete, time varying Dirichlet boundary conditions for heat equation in pdepe
L = 29; x = [0:1:L]; t = [0:1:15]; m = 0; uUpper = trimmedTempData(1,1:16); uLower = trimmedTempData(end,1:16); t0 = trimm...

etwa 3 Jahre vor | 0

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Predicting the value at y(t=8) using my model
thetaL(1)*8 + thetaL(2)

etwa 3 Jahre vor | 0

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how to plot a summation function in matlab using a for loop
For reference: syms k t f(t) = 4*symsum((-1)^(k+1)*cos(k*t)/k^2,k,1,Inf) f(0) fplot(f+2/3*pi^2,[-2*pi,2*pi])

etwa 3 Jahre vor | 0

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How do I get random variables generated from a distribution in [-1, 1]?
The curve for the "noisy h" looks wrong although your formula for the "noisy h" is correct. The noise is h.*0.01*(2*rand(2*N,...

etwa 3 Jahre vor | 0

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Fsolve and initial guesses
You already received several responses for this question here: https://uk.mathworks.com/matlabcentral/answers/1973704-interpret...

etwa 3 Jahre vor | 1

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Find value at which a line changes its slope
Plot gradient(y)./gradient(x) over x to get an approximation of the derivative of your curve and see if this curve can give you ...

etwa 3 Jahre vor | 1

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Why do i keep on receiving the same error? Please show me how to fix the code!
Your function "predprey" must return a row vector, not a column vector: Use function yp = predprey(t, y, a, b, c, d) yp = [a ...

etwa 3 Jahre vor | 0

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Check ode45 for a certain value and start a new solver when these limitations are reached
That's exactly what the Event facility of the ODE integrators does. Look at the "ballode" example: https://uk.mathworks.com/he...

etwa 3 Jahre vor | 1

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Error using fmincon line 619
Why do you solve a linear optimization problem with "fmincon" ? Use "linprog" instead. R = [120.97, 462.26, 231.65, 140.94, 26...

etwa 3 Jahre vor | 1

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MatLab Multiple graphs in one axis
That your measurement curves overlap and those in the literature don't is a fact. You won't be able to hide this by any special...

etwa 3 Jahre vor | 0

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How to do a Taylor expansion with a matrix
Maybe you mean: G = [0,4;4,0]; Gexp = expm(G) or syms t G = [0,4;4,0]*t; Gexp = simplify(taylor(expm(G),t,'ExpansionPoint'...

etwa 3 Jahre vor | 1

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How to use Runge-Kutta orde 4 in sigmoid equation. I want to plot sigmoid equation with Runge kutta orde 4th but my graph is linear. I need help
Why do you use a method for ordinary differential equations to integrate a simple function of the independent variable ? Use "...

etwa 3 Jahre vor | 0

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Interpreting the results of 'fsolve'
Can I trust the variable solutions that is computed for me? An error norm of 0.000177715 is not bad, but "fsolve" couldn't do b...

etwa 3 Jahre vor | 0

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Show more than plot at the same time
help figure https://uk.mathworks.com/help/matlab/ref/figure.html help subplot/tiledlayout https://uk.mathworks.com/help/matla...

etwa 3 Jahre vor | 0

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Nested differentiation in nested integral
I would (without mathematical scruple) differentiate with respect to "r" under both integrals, then use "integral2" to integrate...

etwa 3 Jahre vor | 0

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How would I remove multiple specific elements from an array.
Data = [923 916 932 927 908 931 953 926 919 963]; B = sort(Data,'ascend'); n = numel(B); xmin = B(1); xmax = B(n); Q1 = rou...

etwa 3 Jahre vor | 0

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Trying to apply a general exponential fit to data
As written in the output from CFtool: x is normalized by mean 9.301 and std 6.055. Thus, for x in the equation, you have to ins...

etwa 3 Jahre vor | 0

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Vectorizing Loops over Matrix Elements
If the function f "knows" how to cope with two vectors as inputs that don't have the same size: Yes. E.g. n = 3; m = 5; f = ...

etwa 3 Jahre vor | 0

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hello. how I create function?
You should ask the authors of the code why they didn't include the function "checkHexagonal". Maybe these are the additional fu...

etwa 3 Jahre vor | 0

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