Beantwortet
How to make a color scale like this?
Hi pf, I copied in the image in your posting (a jpeg) and called it image1. That results in a 3d array that is 180x882x3 uint8...

mehr als 5 Jahre vor | 0

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FFT of coupled oscillator from time domain (picosecond) to frequency domain (wavenumber, cm-1)
HI Kunjanni, this occurs because the fft contains both positive and negative frequency (wavenumber) components. Zero frequency...

mehr als 5 Jahre vor | 0

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Exponential function produces error with integrate command
Hi Ben for large x, exp(x) overflows to infinity before the exp(-(x.^2)/2) factor has a chance to bring in down. Try completin...

mehr als 5 Jahre vor | 0

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Even distribution of coordinates subset
Hi Giovanni, here is one method, which assumes that B is supposed to span basically the entire domain of A. Suppose the set of...

mehr als 5 Jahre vor | 0

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Why does pcolor require you to transpose the matrix when you give it x and y vectors?
Hi Darcy. pcolor works in the same fashion as meshgrid, and creates a grid with nx = length(x) columns and ny = length(y) rows....

mehr als 5 Jahre vor | 0

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Undefined function 'sinc' for input arguments of type 'double'.
Hi boutaina, Since it's easy in Matlab to make your own functions, you don't need toolboxes that are (probably not intentionall...

mehr als 5 Jahre vor | 0

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Choose Lyapunov function of a linear system
Hi Cristina, The first part of this is probably telling you what you already know, but denoting C = c*[1 -1 0; 0 1 -1; -1 0 1]...

mehr als 5 Jahre vor | 0

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orthagonal planes and normal vectors
Hi M, A plane satisfies the dot product equation equation r dot v = const where r is the position vector [x y z] and v = [vx ...

mehr als 5 Jahre vor | 3

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How to generate a random complex unitary matrix whose columns each sum up to 1
MODIFIED to replace previous random function Hi Michael, here is one way. It's based on the idea that if the unitary matrix U...

mehr als 5 Jahre vor | 1

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Solving a 3 degree of freedom mass spring damper model
Hi Z^2, Now that you have the K, C and M matrices, you can create a matrix equation to find the natural resonant frequencies. G...

mehr als 5 Jahre vor | 0

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Solve for the constants of a Quartic given the complex roots?
Hi Johnathan, r = [-5 -6 -9.6+25.7i -9.6-25.7i]; p = poly(r) r1 = roots(p) % check p = 1.0e+04 * 0.0001 0.0030 ...

mehr als 5 Jahre vor | 0

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Coding a function for the Fourier Transform.
Hi Anthony, the only problem here is the normalization. For the inverse transform you are dividing by sqrt(N) every time, (N b...

mehr als 5 Jahre vor | 0

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Ignoring NaNs for polyfit
Hello TimaMarie, yes, polyfit doesn't like NaNs. One way out is, just before doing polyfit, toss out the elements of both vari...

mehr als 5 Jahre vor | 0

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Find first item with a certain condition and use it, instead of finding all items with that condition
Hi Thomas, [After reading comments from Bruno and Rik I realized I forgot to mention that in order to get your code to run I ch...

mehr als 5 Jahre vor | 1

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Fzero returning wrong root
Hello Emily If you insert this F_theta = double(F_theta); just after the calculation of F_theta, you will get the correct res...

mehr als 5 Jahre vor | 2

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Solution of differential equations with an input derivative
Hi Pawel, you have e = -x(1) + 1; so de/dt = d/dt(-x(1) + 1) = -dx(1)/dt but dx(1)/dt = (x(2)-x(1))/T2 so you can replace...

mehr als 5 Jahre vor | 1

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quat2angle different result
Hi Sven, it's pretty clear that both test and original have discontinuities because the function producing the angles, probably...

mehr als 5 Jahre vor | 0

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WHY ARE THE COLORS OF MY LEGEND ALL MESSED UP?
Hi OI, One reason that Sylvain posted his comment is that you do not provide working code. And of course your odds of getting ...

mehr als 5 Jahre vor | 1

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Why do I get too high dominant frequencies in FFT
Hi Timo, From your attached data I can see that it's 2 sec at 48 kHz as you said. In your frequency plot, the data seems to be...

mehr als 5 Jahre vor | 0

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fitting only continous line
Hi salman, I have been off taking a look at this problem. The method below uses the fact that what you call the discontinouus ...

mehr als 5 Jahre vor | 0

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ilaplace returns unexpected answer
Hi Abdulla, You mention +- 3 as the coefficient, but are using +-6 in the actual example so I will stay with that. Looking at ...

mehr als 5 Jahre vor | 0

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Changing the amplitude (y-axis) of an FFT back to units of force.
Hi Kev, The first thing is, the time and frequency arrays have to be correct. You are not actually using the 'time' variable b...

mehr als 5 Jahre vor | 1

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How to avoid an Infinite Loop?
Waseem, Nothing in the entire while loop alters either 'sizes' or 'sizesB'. So if sizes(1) ~= sizesB(1), that condition will ...

mehr als 5 Jahre vor | 0

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Calculation of antenna efficiency
Hi Shahar, The plot is of directivity, not gain (confusingly, directivity is sometimes called directive gain). Since directivi...

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How can I obtain the mean and standard deviation of a gaussian PDF
Hi Matthew, here is an example, where mu and sigma are calculated by numerical integration. Also shown are analytical results ...

mehr als 5 Jahre vor | 1

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Why am I getting Complex number results?
Hello Ethan, The reason for this is that at step i = 14, the quantity on the third to last line, (1-(c*y(i)/T)) becomes negativ...

mehr als 5 Jahre vor | 1

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Poisson Boltzmann eq. with an infinite boundary condition
Hi Roi For convenience I will use u in place of psi. An exact solution is tanh(u/4) = A*exp(-x) where A = tanh(1/4) ...

mehr als 5 Jahre vor | 1

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Can I use the PDEPE solver to solve the following dimensionless Transient PFR PDE? If not, what method do you reconmend?
Hello Rogelio, For psi(t,eta) I assume that the boundary conditions are psi(0,eta) = 0 for all eta an...

mehr als 5 Jahre vor | 0

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double peaks in FFT matlab
Hello hamzah the fft is a complex function. Are you plotting only the real part? This problem is occurring because your delta...

mehr als 5 Jahre vor | 0

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How to plot wavelength and wavenumber FFT from intensity data
Hi Arwi, n = 3648, dpix = 8e-9; % 8nm seems small for a pixel width The x array has spacing delx = dpix and is x = delx*(0:...

mehr als 5 Jahre vor | 0