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MatLab eig vs LAPACK
If I had to guess, you don't need to use it. A = randn(500); timeit(@() eig(A)) ans = 0.0800828164545 B = A + A'; timeit...

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How to solve 'Equation solved at initial point' with fsolve?
As is often necessary on a problem like this, it helps to look carefully at what you have. x = sym('x',[1 2]); mu_earth = 39...

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Optimization: Capacitated Facility Location Problem
First, what is the difference between the summation over i in a sum like this: sum(f(i)*yi)) and the dot product of two ve...

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im trying to solve a system of 4 nonlinear equations with 4 unknowns
x = sym('x',[1,4]) eq1 = x(1)+.17*x(1)-x(2)-x(3)-x(4) == 0 eq2 = (((x(3)^(1/2))*x(4))/x(2))-.465797 == 0 eq3 = 2*x(1)-2*x(2)-...

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Another question on eliminating for loops....
Try it. If you can't see ndgrid doing it, then look harder. :) (By the way, lower case l (L) is a really bad variable name to us...

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How to do piecewise linear approximation from x and y points?
x = [20 60 240 480 1440 2880]; y = [0.0278 0.1626 1.8126 4.006 18.2491 44.4084]; plot(x,y,'o-') You have only 6 data points...

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How do I access an element of an array of equations
If x is symbolic, you CANNOT use it in a colon call. But in the end, you did not ask for a symbolic result, but a function of x....

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I want to build the square wave: build a 6 subplot figure to show the time domain, and use respectively 1, 3, 5, 10, 50, 500 frequencies.How can i achieve this?
Solve a problem that is too large for you to handle by breaking it up into small enough chunks to handle. Do you know how to u...

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How to get the numerical rank of the matrix in matlab?
To compute the numerical rank of a matrix, use rank. Surely that seems logical. And you even know about rank. Bu then you seem ...

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Function to solve an equation for a given variable
If it is symbolic problem, then it is trivial. Just assign those variables, subs them in, and use solve. WTP? If it is a numeri...

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How to identify the infeasibility from the set of equality and inequality constraints
You have a scalar problem? But then, you have TWO equality constraints? So a solution will exist only if BOTH equalities are s...

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I wanna make a .mat file
help save

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Problém with graph of implicit function
If you change the value of a, then the implicit function itself changes. So you MIGHT decide to use fimplicit3. But if you need...

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degrees of freedom chi2inv
This really should be asked on a different forum, as only barely about MATLAB, and a good answer requires teaching a class in st...

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error with the trapmf function
You wrote this: x1 = 0:1:25; y1 = trapmf(x, [0 5 15 25]) ; So you created the variable x1. Then you called the function trapm...

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How to determine the relationship between two variables from a plotted graph
Walter is correct in everything said. My answer here is just to expand. Once something becomes no longer linear, what is it? F...

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Power method to determine largest eigenvalue and corresponding eigenvector had some wrong
I would claim you have two problems here. One is a pretty common mistake, the other more subtle. Do you understand that eig nor...

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Magnitude of cross product
syms theta phi r = [2.*sin(phi).*cos(theta) 2.*sin(phi).*sin(theta) 2.*cos(phi)]; P=diff(r,theta); R=diff(r,phi); C = cross(...

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Trouble plottiing a trig function
Ok. You knew you had to use the .^ operator to raise the elements to a power, element-wise. There are also .* and ./ operators, ...

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how to make a 3x3 matrix a 9x1 matrix?
The point to the answers you have gotten is if you want it to run across columns, then you can easily convert columns into rows,...

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RREF with unknown variables
WTP? Why not try it? syms a b c rref([1, 2, 3, a; 4, 5, 6, b; 7, 8, 9, c])

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Various functions depending on X
If the function is symbolic, then use piecewise. help piecewise Note that your function lacks definition, since you do not say...

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How can I fix my issue with regstats "design matrix has more predictor variables than observations"?
Get more data. Simple enough. Supose you want to fit a very simple linear model with say three independent variables. With a co...

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How to derive a function from 6 variables
Knowing which function to use, given 6 independent variables is terribly difficult to know. If you lack knowledge of a good nonl...

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how to pass from x y z plane to toroidal coordinate?
You have a line in three dimensionas, and you want to find the equation of that line in a toroidal coordinate system? First, wh...

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Singular value decomposition method for solving least squares problems
Please stop asking this same question multiple times. If you are asking how to solve a least squares problem of the form A*x = ...

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Finding unknow of equation
I'll use syms here, because it displays things nicely. syms x y a b c d B=[0;0;x;0;0;y] C=[a;b;0;c;d;-2000] So B and C are V...

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Am I writing this exponential function the right way?
You need to learn about the dotted operators. They are used when you will be performing ELEMENT-wise squaring, multiplications, ...

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Interpolate Scattered Data on another mesh
But what is the problem? Using scatteredInterpolant, interpolate set 2 (x,y,z) using the data for set 1. Some of the points fr...

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I want to solve this equation for Xp while I know all others parameters.
In almost all cases when you have a variable that lies both inside, and outside of a nonlinear function, like sin or cos, log an...

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