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What is the problem for the following matlab code for drawing contour plots of R0 against two parameters?
alpha= 1.0*0.0241; beta=0.001936 ; gamma=0.0020255; T=23.3; T0=23; mu_ref = 0.0017; mu1=0.039 ;mu2=0.002894; L=8; L0=8 ; delta...

alrededor de 3 años hace | 0

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fmincon is not working
You must define F = @(x) fun(x(1),x(2)) and pass "F" instead of "fun" to fminunc.

alrededor de 3 años hace | 0

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How to integrate a complicated function?
https://www.wolframalpha.com/input?i=integration&assumption=%7B%22C%22%2C+%22integration%22%7D+-%3E+%7B%22Calculator%22%7D&assum...

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Function optimization with some conditions conditions
The dimensions would be correct if you use b = [b1;b2.';b3.']; instead of b = [b1;b2;b3]; but you'd better post the problem ...

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How do you go about guessing for fitting parameter initializations?
This is a linear fitting problem for which you don't need initial guesses for the parameters: Data = [0.006 334 0.011 276 ...

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How to solve a boundary value problem x"+x'=1, x(0)=1, x(1)=2 , with an impulse condition x(i/3+)=2*x(i/3)+1, x'(i/3+)=3*x'(i/3)-1;
syms t x1(t) x2(t) eqn1 = diff(x1,t,2) + diff(x1,t) == 1; Dx1 = diff(x1,t); eqn2 = diff(x2,t,2) + diff(x2,t) == 1; Dx2 = dif...

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Error: In an assignment A(:) = B, the number of elements in A and B must be the same.
w(i)=w; This line of code makes no sense. You want to assign a vector w to a scalar w(i).

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solving complex matrix with symbolic variables
syms a b c d e f g h k real z1=-30j; z2=0.08+0.40j; z3=-35j; z4=0.10+0.50j; z5=0.10+0.50j; z6=-25j; z7=0.30j; p1=a; p...

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Kindly help me out with this code. its urgent please .thanks
The trigonometric functions sin, cos for an argument x are invoked as sin(x), cos(x),... If they have an exponent, they are eit...

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How can I create a spline with conditions on the middle?
% Set up the problem with 16 conditions for 16 spline coefficients syms a [4,1] syms b [4,1] syms c [4,1] syms d [4,1] ...

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Research of inflexion point - Index exceeds the number of array elements.
You forgot to initialize x as x = [] in the second example.

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Fit a statistical distribution to truncated data
Why should it be justified to fit a dataset of a truncated normal by a normal distribution ? pd_fit_trunc = fitdist(data_trunc,...

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Roots of an equation when two parameters are changed
"num" is a polynomial of degree 7 in M. Thus it has seven roots. But your code only gives one of these seven. So I hope you get ...

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How can i find the roots of the complex equation?
You can get an analytical solution if you substitute y = z^2: syms y p = y^4 + (10548593400*y^3)/42679 + (33343133111071335000...

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How to solve delay differential equations with computed history (not constant)
Save the results of the non-delayed ode in arrays T and Y, create an interpolation function fun_history = @(t) interp1(T,Y,t) ...

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use of fminimax solver in matlab for optimization
z seems to be a constant in your objective function. Thus it doesn't influence the result of the optimization and doesn't need t...

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Arrhenius model fitting using fminsearch
Your model function σ(T) = σ_ref * exp(-Ea/(kT)) does not have a maximum. Thus it is not suited to reflect your measurement data...

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maximization with fmincon which of the two codes provided do the correct job
I suggest using a function instead of a function handle. I compared it with your implementation and random matrices for W and R...

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Arrhenius model fitting using fminsearch
Imagine you get Ea = 3 and k = 6 in one run and Ea = 12 and k = 24 in a second run. Both solutions give the same quality of fitt...

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Assign a value to a matrix element defined as a variable
prop = @(x)[[x(1)*ones(11,1);x(2)*ones(12,1)],[x(3)*ones(11,1);x(4)*ones(12,1)],zeros(23,1),zeros(23,1)]; prop([1 2 3 4])

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can find regression and curve fit for given equation
Since your equation can be rearranged as dy/dx = 1/c * log((m-a)/b) your model assumes that dy/dx is equal to a constant that ...

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lsqnonlin - error in finite differences, arrays of incompatible size
The size of your problem changes in the course of the computation from 685 to 650 functions to be minimized (see above). This wi...

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How to turn off the simplification condition?
Then use expr = simplify(expr,'IgnoreAnalyticConstraints',true)

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Least Squares with constraint on absolute value
rng("default") n = 32; y = rand(n,1) + 1i*rand(n,1); B = rand(n) + 1i*rand(n); x0 = rand(n,1) + 1i*rand(n,1); x0 = [real(x0...

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Plotting the result of ODE that as a integral component.
For the first one substitute z(t) = integral_{tau=0}^{tau = t} y(tau) dtau and solve the system of differential equations y'...

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How can I integrate the math equation (attachment) numerically?
Just as it's written: result = integral(@(Ex)Ex.*(NL(Ex)-NR(Ex)).*T(Ex),0,Inf) Of course, I don't know whether you defined the...

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Plot the Diagram of the probability of some data
I don't know what exactly you mean by "Probability Diagram", but the usual way is to use histogram(data,'Normalization','pdf')

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all function B = all(A < 0.5,3)
But why does this yield the same result? Because A has only 2 dimensions, not 3 or 4. Thus "all" operates on all elements separ...

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Unable to solve boundary condition problem
"ode == 0" cannot be explicitly solved for D2y. But given y and Dy, you can try to use Newton's method to supply D2y. Define a...

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How to ramp a boundary condition in bvp4c
y_0 = 0.1; y_list = linspace(0,y_0,1000); fy_list = y_list.^(1.5); f_inter = @(y)interp1(y_list,fy_list,y); L = 10; n = 100...

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