Answered
solving a nonlinear equation with complex numbers
syms R positive % positive implicitly implies real also syms X real syms Zo Z=(R*1i*X/(R+1i*X)); r=(Z-Zo)/(Z+Zo) r = simpli...

1 year ago | 0

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Warning: Equation is badly conditioned. Remove repeated data points or try centering and scaling.
Do NOT use polynomials to model data like this In fact, do not use high order polynomials, pretty much ever. FR = load('FR.txt'...

1 year ago | 2

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Recursively reversing large vector efficiently
An old question with an already good answer. Regardless, it explicitly asks about recursive schemes to flip a vector. And I can ...

1 year ago | 1

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Fixing biased random number generation
What is the goal of this? That is a good question, as asked by @埃博拉酱. You should recognize that the result of this operation w...

1 year ago | 0

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My end value "tc2" comes out as "NaN + NaNi", in the following script and I cant figure out why.
A NaN means you are doing some operation that has no meaningful result. For example, what is 0/0? 0/0 A mathematician will tel...

1 year ago | 0

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Sparse matrix memory understanding
I think you missed a zero. By the way, 5% sparse is NOT at all what I would consider sparse, or for there to often be a gain. L...

1 year ago | 0

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Fittype and fit do not work as expected (in a curve fitting)
x = [1 4 9 15 25 35 45 55 65 75 85 95 150 250 350 450 900]; y = [0 335 28 37 9 4 3.5 2 1 0.7 0.6 0.5 0.3 0.1 0.01 0.005 0.001];...

1 year ago | 2

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Newton Rapson method code question
Actually, this is surprisingly nice looking code. (A true compliment from me, given most of the student codes we see on here!) Y...

1 year ago | 1

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Converting an STL file to a 3D Surface/Equation
Um, I think you misunderstand a few things. It seems the STL model actually has thickness. So you have exported the entire thi...

1 year ago | 0

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I want the genetic algorithm to begin with intial parameter and this is not happened can you help me for making the genetic algorithm begin with the intial parameter?
I think you don't understand GA. It does not use a start point. It starts with an initial population of points from the sample s...

1 year ago | 0

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How do I convert a symbolic expression to a string?
Simple enough. Note the changes I made to your last line only. I could also have done it using character vectors, but then I wou...

1 year ago | 1

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Answered
Plotting a volume in 3D
Your question is somewhat incomplete, as to what you mean by plotting a solid volume. I'll assume you may mean something like th...

1 year ago | 0

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How to numerically calculate volume under the curve?
You have a surface. (Not a curve as I might say.) How do you compute the area under that surface? Simple. Just call trapz twice....

1 year ago | 1

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Answered
ode45 integration issues for some choices of physical parameters,
This is an absolutely classic case for a stiff system, where for some sets of system parmeters, you have two or more things happ...

1 year ago | 0

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How to choose 60 unique coordinates ('A') from 600 coordinates('B'), nearest to 60 other coordinates('C')
As I pointed out to @Voss and @Star Strider, if the points in B mst be unique, then there is an issue. If you simply choose the ...

1 year ago | 1

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finding variable of a given equation
gamma is a really bad choice of variable names, since gamma is itself a very useful function in MATLAB. Try to avoid doing these...

1 year ago | 1

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solving nonlinear equation using newton method
You just misunderstand how to use the exponential function. In MATLAB, e^x is written as exp(x). That makes your fn as: fn = @...

1 year ago | 0

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How to Set a Minimum Step Size for Variables in GA Solver (Global Optimization Toolbox)?
Really easy. Don't think of a step size for the GA solver. It does not take steps anyway, not like fmincon or other solvers of ...

1 year ago | 1

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Answered
Solution of system of nonlinear equations
This will be literally impossible to do in double precision, given the huge dynamic range of those coefficients. But we can look...

1 year ago | 0

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Support with interpolation using interp3 in MATLAB
And ... your question about MATLAB is? Far too much vague verbiage to know what is the problem. If you want to know how to use i...

1 year ago | 0

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Ode45 g and dg
You cannot use the variable dg4, before it is defined. And we see you do this: dg2=m*A+k*g(1)+h1*k*g(3)+dg4 ... dg4=h1*k2x*g(...

1 year ago | 1

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fitting with custom equation
(I assume you intended to write 1/y, and not I/y, where the variable I is not defined.) y = [1.6E5 2.5E5 4.1E5 8E5 1E6 2E6 7E6 ...

1 year ago | 1

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improve fit compared to R
x = [0.858734025700000 0.975248753121875 1.02525125312812 1.13140821289062 1.15927407430000 1.18768630564687 1.21665290240...

1 year ago | 1

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Some .jpeg photos can not be processed by Matlab code.
I've not even looked at your code. But you have jpg images, uint8 code values. So I wonder if adding the code values caused an o...

1 year ago | 0

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Finding concave hull around abstract shape
I don't know the soure of this data. But, can you start with the two pieces as separate entities, form polyshapes from each, and...

1 year ago | 1

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Numerical Integration MATLAB vs Python/VBA
This is difficult to say, because we know virtually nothing. First, does the problem arise from the use of subtly different da...

1 year ago | 0

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Warning: Explicit solution could not be found./ empty sym
Does an analytical solution exist for EVERY equation you can write down? (No.) Even if such a solution does exist, is it certain...

1 year ago | 0

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fmincon is not converge
It is very rarely easy to know why a solver fails to converge on a messy thing like this. But you should never let it come to th...

1 year ago | 0

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Is there any way to perform an at least partially symbolic smulation (using ODE or discrete model) in simulink?
Essentially, no. This is a frequent question about tools like ODE45 too. Simulink is a purely numerical tool, like ODE45 and oth...

1 year ago | 0

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d solve command matlab
syms e P S A t m V0 t0 V(t) real The point being that assumptions can apply only to variables, not functions. V(t) is a functio...

1 year ago | 0