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# Torsten

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2,560 total contributions since 2013

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what numerical approach is used for bvpinit?
In bvpinit, the user just specifies a guess on how the solution of the boundary value problem might look. A numerical method i...

6 hours ago | 0

element wise product matrix-vector
Y_t = bsxfun(@times,Y_t,w)

2 days ago | 0

Unexpected output when trying to plot the solution to a system of nonlinear differential equations
Use hold on between the two plot commands.

2 days ago | 1

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How do I make a function work with vectors?
tanH = (exp(x)-exp(-x))./(exp(x)+exp(-x))

3 days ago | 0

How can I put an integral inside a for loop when the bounds depend on the loop's variable?
Phi_ij1 =@(i,j) integral2(@(y,x) B_zi(i,x,y),0,y_min1(j),0,@(y)x_max1(y,j));

4 days ago | 1

L2 norm of the column
M_norm = normc(M)

4 days ago | 0

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Curve fitting toolbox - gaussian curve to histogram with no workspace data for the y - value
I think Matlab's "mle" is what you want instead of the curve fitting toolbox.

7 days ago | 0

lsqnonlin and stretched exponential function
error_bounds = nlparci(x,residual,'jacobian',J) after the call to lsqnonlin. If you don't have a toolbox with nlparci, search ...

8 days ago | 0

I'm getting an error related to fmincon
If you mean the eigenvalue largest in magnitude, this should give you a start. Incorporating fmincon can automatize the search ...

8 days ago | 0

root of nonlinear equation
ft = @( c ) 0.25* ... instead of ft = 0.25* ...

9 days ago | 0

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stop Ode45 when y is less than a value
As defined, ode45 expects myEvent to have 2 input parameters, but you use 3. Use Opt = odeset('Events',@(t,u)myEvent(t,u,minu)...

9 days ago | 0

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How to add the value of the 3 highest elements automatically from a vector?
[~,idx]=maxk(y,3); y(idx)=y(idx)+sx; y

9 days ago | 0

Extracting values that are greater than the threshold

9 days ago | 0

Fitting to an intergral
Use "ArrayValued=true" as option in the call to integral.

10 days ago | 1

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Hello guys, I need help.
[X1,X2,X3]=ndgrid(x1,x2,x3); Z=f(X1,X2,X3); %assumes f is vectorized M=[X1,X2,X3,Z]; [~,idx]=sort(M(:,4)); sortedM=M(idx,:...

10 days ago | 0

Temperature ramp then keep it at constant temperature
Copy the lines where you define the global parameters to the beginning of function "fun" and remove them in the upper part of th...

10 days ago | 0

Best way to solve my implicit equation
Use "fzero" or "fsolve".

10 days ago | 1

How can i implemente this PDE system?
Use "pdepe". You will need to specify four boundary conditions for this solver, although only two for the T equation were neces...

11 days ago | 0

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For Loop Which Skips Numbers Based on Row Vector
Use "setdiff" to remove the row vector elements from the range of the for-loop and name the vector v. Then simply type for v ...

11 days ago | 0

Euler function where you can define equation, starting x and y values, number of steps and the step length
Use g = f or g = @(x,y) f(x,y) instead of g = @(x,y) f.

11 days ago | 0

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Integrate for a specific period of time
t=0:.01:10; x = zeros(numel(t)); x(1) = 1; fun_xdot = @(t,x) -2*(x^3) + sin(0.5*t)*x; for i = 1:numel(t)-1 x(i+1) = x(i...

7 months ago | 0

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Why does fsolve seem not iterate towards the solution?
k = 0.1007; rZ = 12.6518; Rs = 0.164; Cmax = 7.0e-11; W = 1.704e8; iZ = 14.5273; Ls = 1.1e-7; a1 = (k/1000)^2*(rZ-Rs); ...

7 months ago | 0

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I am getting this error "Index in position 1 is invalid. Array indices must be positive integers or logical values." Kindly help me clear this.
i and j are not defined at this line of your code ; they are first introduced one line later.

7 months ago | 0

Finding Linear regression equation
x = [65 65 62 67 69 65 61 67]; y = [105 125 110 120 140 135 95 130]; X = [ones(numel(x),1),x.']; p = X\(y.'); b = p(1) m ...

7 months ago | 0

Non linear least squares for a system of equations
fun = @(z)[z(1)^0.5*Ydata+z(2)-X1data,... z(1)^0.1*Ydata+z(2)-X2data,... z(1)^0.15*Ydata+z(2)-X3data]; ...

7 months ago | 1

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How to iterate with fsolve to find Mach number
function main pt2pinf = [1.9, 2.7, 3.5, 4.3, 5.1, 5.9, 6.7, 7.5, 27.5, 47.5, 67.5 ,87.5 ,107.5,127.5, 147.5, 200, 252.5, 305,...

7 months ago | 0

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Setting of mass matrix
options = odeset('RelTol',1e-9,'AbsTol',1e-9*ones(608,1),'Mass', @(t,y)diag([ones(1,604) sin(t) 1 1 0])); or options = odeset(...

7 months ago | 2

How do I declare and iterate a variable in an ODE driver file?
yold = -Inf; Ssnh_in_1 = 1; [t,y]=ode15s(@(t,y)pha_cont(t,y,Ssnh_in_1),[0,15],y0); ynew = y(end,3); while yold < ynew Ssn...

7 months ago | 0

| accepted