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Solving coupled system of second order differential equations symbolically
Like the Greek godess used to say: Just do it!: y'' = k/m * y + w/m * z, z'' = J/I * z + w/I * y, syms t syms y(t) z(t) syms...

3 månader ago | 0

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Answered
Convert netcdf time ('minutes since 2013-2-1 00:00:00') to actual date
Remember that datenum is in (fractional) days, while your netcdf-time is in minutes. It seems likely that you want to do: t1 = ...

3 månader ago | 1

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Solve systems of equations graphically
You can start investigating the surfaces of the functions f1(x,y) = x.^2+y.^2-29 and f2(x,y) = y.^2-4*x.^2-9 with something like...

3 månader ago | 0

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ODE45 outputs only zeros
When you have discontinuities in the ODEs (the derivative of command) then the safe approach is to separate the integration into...

3 månader ago | 0

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Answered
Unable to perform assignment because the left and right sides have a different number of elements.
It appears because you try to squeeze in/stretch out an array with some number of elements into different number of elements of ...

3 månader ago | 1

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how to load mutiple mat files which has names in 'YYYYMMDD.mat' format?
You could do something like this, provided you have the filenames-of-interest: for iFiles = numel(dataFiles):-1:1 Sloaded{i1...

3 månader ago | 0

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Answered
3 Differential equation using 4th order runge kutta
You have a function for a 2-D system of ODEs. That then is messed up: function diffeqs =ode_Q10(t,var) % t = var(1); % This ov...

3 månader ago | 1

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Answered
Rotation Matrices - omega phi kappa vs yaw pitch roll
If you have mixed up the order of the rotations you might step through the different combinations of rotations and sign-conventi...

3 månader ago | 0

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How can I perform large sparse matrix multiplication efficiently when one sparse matrix is block diagonal?
Shouldn't straight summation be preferable for the calculations of sums rather than doing it by way of matrix multiplication. Pe...

3 månader ago | 0

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How can I convert deformation data into FRF using FFT?
Simply use fft? That will give you the complex discrete Fourier-transform. If you do: fS = fft(S); % fS will have "DC"-componen...

3 månader ago | 0

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Answered
How to differentiate between an index and a value in a function?
Your function J expects a single input as defined. I get: J_0 = J(x_0); to run without problems... HTH

3 månader ago | 0

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Looping through 4 Images that have fixed names
You can for example put the filenames into a cell-array: imFileNames = {'im1.jpg','im2.png','im3.jpeg','im5.tiff'}; Then you c...

3 månader ago | 0

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Answered
Why am i getting this error message? "Array indices must be positive integers or logical values."
In matlab (and most other programming-languages) you will have to write out the multiplication-operator (* for matrix multiplica...

3 månader ago | 1

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Does anyone have the periodic cubic spline codes in matlab?
You will find plenty of examples of spline-tools with different levels of support for periodic boundary-conditions on the file e...

3 månader ago | 0

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Multiply two griddedInterpolant functions
If you have 2 functions f(x,y) and g(x,y) you can evaluate the product on your selected grid-points and multiply them: fx_at_xy...

3 månader ago | 0

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History function for ODE45
Since ode45 solves systems of first-order differential equations on the standard form the history does not matter, so I've never...

3 månader ago | 1

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how to plot two different plots with different axis in a single graph?
Have a look at the documentation and help for yyaxis. There you should find illustrating examples doing what you want. Possibly ...

3 månader ago | 0

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How to write a code for plotting a Poincare map for the analysis of a double pendulum and also How to simulate the motion of the double pendulum.
You will find a couple of contributions on the file exchange for Poincare-maps, the first seems promising: FEX-hits on "poincare...

3 månader ago | 0

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area of water body in a grey color image
If the water-surface are flatter than the not-water-surfaces (seems reasonable assumption for standard optical satellite imaging...

3 månader ago | 0

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solve a complex second order differential equation
The first step is to convert your second-order ODE to two coupled first-order ODEs: Then you should write that ODE-system as ...

3 månader ago | 0

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2D Minimization problem, not good for fminsearch?
For problems like these (It seems likely that your function has multiple local minima or at least very very flat regions) the be...

3 månader ago | 0

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Error using * Incorrect dimensions
For problems like these you should learn to run the code line-by-line at the command-line prompt. Then check the size and type o...

3 månader ago | 0

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Can someone please drop the code for ICA( independent component analysis) for image segmentation on matlab for classifying thermal images
Look on the file exchange for ICA-implementations: ICA at FEX Get fastICA from the/(a significant) source: FastICA Then the ma...

3 månader ago | 0

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Integer eigenvalues in Matlab
Since you have a matrix and want the eigenvalues then the best approach seems to be to actually calculate the eigenvalues. For t...

3 månader ago | 0

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How to solve simultaneous equations?
Using symbolic tools you have solve - look at the help and documentation for that function for examlpes. Your problem should red...

3 månader ago | 0

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How to extract data from a function or functions. Also how to export this data to excel.
Your functions have their own name-space where the variables that are defined exists (in addition to the input variables that yo...

3 månader ago | 2

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how to Solve 4 Equation and 3 unknown
When you have four non-linear equations with three unknowns you cannot, in general, expect to get a symbolic solution. For these...

4 månader ago | 0

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fitting data to system of ode
You will find the answer to this problem in a link to yet another answer (by Star Strider) here: fit-a-parameterised-ode-solutio...

4 månader ago | 0

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How to solve differential equations with varying constants
For the case you describe you have to add information about how X and p varies with time. Are they constant over some fixed inte...

4 månader ago | 0

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What should go in a next-generation MATLAB X?
Allow elementary mathematical operations on function-handles. So instead of writing the sum of two functions as: f1 = @(x) x.^2...

4 månader ago | 0

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