Answered

Spring mass system subjected to impulse excitation

You seem to have misunderstood how matlab integrates ODEs. Your ODE-function, impulse, should return the derivatives, and , at...

Spring mass system subjected to impulse excitation

You seem to have misunderstood how matlab integrates ODEs. Your ODE-function, impulse, should return the derivatives, and , at...

1 day ago | 0

Answered

Is It Necessary to Select an Odd Span for Smoothing Data Using Moving Average Filter?

You can check what happens when smooting by averaging over an even number of points. simply use convolution to carry out the ave...

Is It Necessary to Select an Odd Span for Smoothing Data Using Moving Average Filter?

You can check what happens when smooting by averaging over an even number of points. simply use convolution to carry out the ave...

2 days ago | 0

Answered

dispersion relation normalization ion acoustic

Expand the definitions of and . Then you get a proper expression for the ion-accoustic dispersion relation. To plot it in some ...

dispersion relation normalization ion acoustic

Expand the definitions of and . Then you get a proper expression for the ion-accoustic dispersion relation. To plot it in some ...

3 days ago | 0

Answered

Convert interpolation function to symbolic

You already get a piecewise polynomial out of pchip. That is a symbolic function - though not on the form expected by the symbol...

Convert interpolation function to symbolic

You already get a piecewise polynomial out of pchip. That is a symbolic function - though not on the form expected by the symbol...

16 days ago | 1

| accepted

Answered

How to get a value from inside a function?

So we know something about your functions, but not much more than the most general stuff. If you write your function fun_a somet...

How to get a value from inside a function?

So we know something about your functions, but not much more than the most general stuff. If you write your function fun_a somet...

20 days ago | 1

| accepted

Answered

how to extract variables from ode45

My pedestrian-layman approach to this type of problem is to integrate the ODE, typically with t = t0:dt:tend, then when I have y...

how to extract variables from ode45

My pedestrian-layman approach to this type of problem is to integrate the ODE, typically with t = t0:dt:tend, then when I have y...

21 days ago | 0

Answered

Infinite recursion in code to graph second order differential equations

Let's analyse what's happening here. When you call odefcn from the command-line 1, the first thing matlab does is to overwrit...

Infinite recursion in code to graph second order differential equations

Let's analyse what's happening here. When you call odefcn from the command-line 1, the first thing matlab does is to overwrit...

22 days ago | 0

| accepted

Answered

Scatter 2D plot with specific colorbar

You can try something like this: imagesc % Just to get something to show axP = get(gca,'position'); % Create axes for colorba...

Scatter 2D plot with specific colorbar

You can try something like this: imagesc % Just to get something to show axP = get(gca,'position'); % Create axes for colorba...

26 days ago | 0

| accepted

Answered

whats is presice compute time in matlab

These fluctuations are "kind of expected", your computer does a lot of other stuff in addition to running matlab which gives the...

whats is presice compute time in matlab

These fluctuations are "kind of expected", your computer does a lot of other stuff in addition to running matlab which gives the...

27 days ago | 0

Answered

FFT of sine wave shows unexpected spectral widening

Try this: subplot(1,2,1) plot(templeS) axis tight ax = axis; axis([[-30 0]+ax(2) ax(3:4)]) subplot(1,2,2) axis tight ...

FFT of sine wave shows unexpected spectral widening

Try this: subplot(1,2,1) plot(templeS) axis tight ax = axis; axis([[-30 0]+ax(2) ax(3:4)]) subplot(1,2,2) axis tight ...

28 days ago | 0

| accepted

Answered

Add n days to juliandate

It seems to work just fine as far as I can see. When I compare: jd0 = juliandate(2020, 2, 14); jd0p100 =juliandate(2020, 2, 14...

Add n days to juliandate

It seems to work just fine as far as I can see. When I compare: jd0 = juliandate(2020, 2, 14); jd0p100 =juliandate(2020, 2, 14...

1 month ago | 0

Answered

How to find the best parameters to fit damped oscillations curves

If you plot your data you should be able to see that the zero-crossings are increasingly further apart. That means that your mo...

How to find the best parameters to fit damped oscillations curves

If you plot your data you should be able to see that the zero-crossings are increasingly further apart. That means that your mo...

1 month ago | 1

Answered

How can I improve code efficiency?

First step of improving code is to run the scripts and functions with the profiler on (seel documentation and help for profile) ...

How can I improve code efficiency?

First step of improving code is to run the scripts and functions with the profiler on (seel documentation and help for profile) ...

1 month ago | 0

Answered

Some question about a special code for solving an ODE system by Runge-Kutta method

Since u1 and u2 depends on p1, p2 and p3, that in turn will depend on time, you have 6 coupled ODEs. The best(?) way to solve th...

Some question about a special code for solving an ODE system by Runge-Kutta method

Since u1 and u2 depends on p1, p2 and p3, that in turn will depend on time, you have 6 coupled ODEs. The best(?) way to solve th...

1 month ago | 0

| accepted

Answered

Curve fitting of a custom equation with a predefined value

For this type of problems I typically use the basic optimization-functions of matlab - either fminsearch or lsqnonlin depending ...

Curve fitting of a custom equation with a predefined value

For this type of problems I typically use the basic optimization-functions of matlab - either fminsearch or lsqnonlin depending ...

1 month ago | 0

| accepted

Answered

how to get eigenvalues of a function matrix?

To calculate the eigenvalues of H you have to chose, either to use your implementation where H is a handle to a function returni...

how to get eigenvalues of a function matrix?

To calculate the eigenvalues of H you have to chose, either to use your implementation where H is a handle to a function returni...

2 months ago | 0

| accepted

Answered

How do I create a new folder each time I run a code?

This is easily solved: dirname = fullfile(path_2_root_dir,sprintf('NewFolder-%s',datestr(now,'yyyymmdd-HHMMSS'))); mkdir(dirna...

How do I create a new folder each time I run a code?

This is easily solved: dirname = fullfile(path_2_root_dir,sprintf('NewFolder-%s',datestr(now,'yyyymmdd-HHMMSS'))); mkdir(dirna...

2 months ago | 0

Answered

Images don't show properly with imshow after certain calculation

When you do things like this the errors are always (in my experience) in different normalizations and type-castings. To work the...

Images don't show properly with imshow after certain calculation

When you do things like this the errors are always (in my experience) in different normalizations and type-castings. To work the...

3 months ago | 0

| accepted

Answered

Press " " to rename 4 instances of "VariableName1" to "VariableName2"

That ought to be the return key... HTH

Press " " to rename 4 instances of "VariableName1" to "VariableName2"

That ought to be the return key... HTH

3 months ago | 0

Answered

How to compute SVD of a matrix without using in-build SVD command?

So this is a homework task, right? (Unless you come up with a good reason this is the case everyone have to come to this conclus...

How to compute SVD of a matrix without using in-build SVD command?

So this is a homework task, right? (Unless you come up with a good reason this is the case everyone have to come to this conclus...

3 months ago | 0

Answered

analytical solution of ODEs

This should be done thisly: syms r syms T(r) dTdr = diff(T) d2Tdr2 = diff(T,2) T = dsolve(1*d2T+((1/r)*dT) ==1,T(0.005)==20...

analytical solution of ODEs

This should be done thisly: syms r syms T(r) dTdr = diff(T) d2Tdr2 = diff(T,2) T = dsolve(1*d2T+((1/r)*dT) ==1,T(0.005)==20...

3 months ago | 0

Answered

How to graphically/interactively select region of interest from 3D point cloud data

In newer versions of matlab there seems to be just such a feature, see: ROI.CUBOID For older versions of matlab (I vaguely rec...

How to graphically/interactively select region of interest from 3D point cloud data

In newer versions of matlab there seems to be just such a feature, see: ROI.CUBOID For older versions of matlab (I vaguely rec...

3 months ago | 0

| accepted

Answered

Obtaining a equation in two variables (x and y) from a set of data points

What you should do depends on your objective. If you very explicitly want a function you could use spap2 (and perhaps some of it...

Obtaining a equation in two variables (x and y) from a set of data points

What you should do depends on your objective. If you very explicitly want a function you could use spap2 (and perhaps some of it...

3 months ago | 1

| accepted

Answered

Hello, we have received a Matlab code in school and the assignment is to explain what it means. I wonder if anybody could take us through the code and explain it?

At the matlab command-line prompt type: dpstop in nameiofscript where nameiofscript is the name of the script-file. Then you r...

Hello, we have received a Matlab code in school and the assignment is to explain what it means. I wonder if anybody could take us through the code and explain it?

At the matlab command-line prompt type: dpstop in nameiofscript where nameiofscript is the name of the script-file. Then you r...

4 months ago | 0

Answered

How to obtain CDF from large dataset?

Have a look at the help and documentation of the function ksdensity - that is one way to do this with the least amount of assump...

How to obtain CDF from large dataset?

Have a look at the help and documentation of the function ksdensity - that is one way to do this with the least amount of assump...

4 months ago | 0

Answered

Difference in frequency domain between mp3 and wav

There are some small differences. You should also try to compare the spectrograms of the two signals, see the help for spectrogr...

Difference in frequency domain between mp3 and wav

There are some small differences. You should also try to compare the spectrograms of the two signals, see the help for spectrogr...

4 months ago | 0

Answered

How to edit matlab saved file?

I think something like this should work: filename2edit = 'something.mat'; load(filename2edit,'X2change') X2change(3) = 12; s...

How to edit matlab saved file?

I think something like this should work: filename2edit = 'something.mat'; load(filename2edit,'X2change') X2change(3) = 12; s...

4 months ago | 0

Answered

I would like to plot Histogram and relative frequencies from a given dada.txt. I already plot time series plot for the given data. KIndly help me to plot histogram and relative freqs.

Have a good look at the help and documentation of histogram function. It should let you solve this task easily. HTH

I would like to plot Histogram and relative frequencies from a given dada.txt. I already plot time series plot for the given data. KIndly help me to plot histogram and relative freqs.

Have a good look at the help and documentation of histogram function. It should let you solve this task easily. HTH

4 months ago | 0

Answered

Solving 4th order ode problem

In general you convert a high-order ODE to a set of first order ODEs like in this example below (I will use a simple equation of...

Solving 4th order ode problem

In general you convert a high-order ODE to a set of first order ODEs like in this example below (I will use a simple equation of...

4 months ago | 0

Answered

partial differentating a matrix by a vector

Have a look at the help and documentation for jacobian. HTH

partial differentating a matrix by a vector

Have a look at the help and documentation for jacobian. HTH

4 months ago | 0

| accepted