Answered

Polyfit polynomial badly conditioned on Linux whereas on Mac no warnings

In R2022a the Vandermonde matrix V is built the condition number is aroun 1e12, and the resolution is carrired out by [p, rankV...

Polyfit polynomial badly conditioned on Linux whereas on Mac no warnings

In R2022a the Vandermonde matrix V is built the condition number is aroun 1e12, and the resolution is carrired out by [p, rankV...

23 dagar ago | 2

| accepted

Answered

How to do a Fourier analysis with a mask?

Discrete Fourier transform always has unwanted artefact on finite region, due to boundary wrapping jumps, even for rectangular r...

How to do a Fourier analysis with a mask?

Discrete Fourier transform always has unwanted artefact on finite region, due to boundary wrapping jumps, even for rectangular r...

23 dagar ago | 0

Answered

Simultaneous sortrows() for all slices of a 3D matrix?

Code applicable for n == 2 and N < 256 only: % Parameters: N = 20; n = 40; m = 2; d = 200000; % Generate an example matrix...

Simultaneous sortrows() for all slices of a 3D matrix?

Code applicable for n == 2 and N < 256 only: % Parameters: N = 20; n = 40; m = 2; d = 200000; % Generate an example matrix...

23 dagar ago | 1

| accepted

Answered

Simultaneous sortrows() for all slices of a 3D matrix?

Somewhat faster % Parameters: N = 20; n = 40; m = 2; d = 200000; % Generate an example matrix 'A': A = randi(N,n,m,d,'u...

Simultaneous sortrows() for all slices of a 3D matrix?

Somewhat faster % Parameters: N = 20; n = 40; m = 2; d = 200000; % Generate an example matrix 'A': A = randi(N,n,m,d,'u...

24 dagar ago | 1

Answered

For loop over function handle, how to speed up the code?

If your handle A can accept a matrix as input and the calculation of A(B) is not bottleneck, you can work by chunk % N = 2^16; ...

For loop over function handle, how to speed up the code?

If your handle A can accept a matrix as input and the calculation of A(B) is not bottleneck, you can work by chunk % N = 2^16; ...

24 dagar ago | 0

Answered

Why tic/toc reports slower times the first five iterations?

If I remember, the JIT optimizer decides to kick in when the same code is detected by execution engine to run few times (5).

Why tic/toc reports slower times the first five iterations?

If I remember, the JIT optimizer decides to kick in when the same code is detected by execution engine to run few times (5).

24 dagar ago | 1

Answered

MATLAB CODE FOR ROOT MEAN SQUARED

To my book the mean should not be removed in calculation of RMS M = rand(3,100); [rows, columns] = size(M); cal_rms = zeros(r...

MATLAB CODE FOR ROOT MEAN SQUARED

To my book the mean should not be removed in calculation of RMS M = rand(3,100); [rows, columns] = size(M); cal_rms = zeros(r...

24 dagar ago | 0

Answered

Adding members to a matrix changes other members in the matrix

It is simply the display on screen that scale the data to largest value. The data is untouched interally.

Adding members to a matrix changes other members in the matrix

It is simply the display on screen that scale the data to largest value. The data is untouched interally.

24 dagar ago | 0

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Answered

Smoothing/splining data with a limit to the slope of the smooth fit

Using this File Exchange, its is not easy to find a combination of parameters to make it "works". I think it is difficult and th...

Smoothing/splining data with a limit to the slope of the smooth fit

Using this File Exchange, its is not easy to find a combination of parameters to make it "works". I think it is difficult and th...

24 dagar ago | 0

Answered

How can I compute the Area and the Centroid of the following shape?

xA = 0; xB = 1; a = 9.2; c = 0.5; sfun = @(x)sigmf(x, [a c]); Area = integral(@(x)sfun(x),xA,xB); xc = integral(@(x)...

How can I compute the Area and the Centroid of the following shape?

xA = 0; xB = 1; a = 9.2; c = 0.5; sfun = @(x)sigmf(x, [a c]); Area = integral(@(x)sfun(x),xA,xB); xc = integral(@(x)...

25 dagar ago | 1

Answered

Minimizing an equation to 0

This minimize the frobenius norm, or l2 norm of the vectorized residual matrix (divided by sqrt(numel(A)) you'll get the rms) k...

Minimizing an equation to 0

This minimize the frobenius norm, or l2 norm of the vectorized residual matrix (divided by sqrt(numel(A)) you'll get the rms) k...

26 dagar ago | 0

Answered

Why ''int'' and ''integral'' return different answers

I think the problem is more subttle than the simple presence of singularities. Some "mild" singularity can be handlle correctly ...

Why ''int'' and ''integral'' return different answers

I think the problem is more subttle than the simple presence of singularities. Some "mild" singularity can be handlle correctly ...

27 dagar ago | 0

Answered

How do I plot this set as 3d region in matlab?

Code that plot ALL the boundaries of the domain x = 0; y = 0; c = 1+x^2+y^2; f1 = @(u,v,z) z - (u.^2 + v.^2 + c); f2 = @(...

How do I plot this set as 3d region in matlab?

Code that plot ALL the boundaries of the domain x = 0; y = 0; c = 1+x^2+y^2; f1 = @(u,v,z) z - (u.^2 + v.^2 + c); f2 = @(...

28 dagar ago | 2

Answered

Randomise vector numbers to maximum variance

A = repmat([10 repmat([repmat(0, 1, 2), 1 repmat(0, 1, 2)], 1, 5)], 1, 20);

Randomise vector numbers to maximum variance

A = repmat([10 repmat([repmat(0, 1, 2), 1 repmat(0, 1, 2)], 1, 5)], 1, 20);

28 dagar ago | 0

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Answered

How od i generate random numbers whose sum is constant?

If the numbers are supposed to be >= 0 with precribed sum, a simple method is n = 100; s = 10; Y = -log(rand(1,n)); X = s ...

How od i generate random numbers whose sum is constant?

If the numbers are supposed to be >= 0 with precribed sum, a simple method is n = 100; s = 10; Y = -log(rand(1,n)); X = s ...

28 dagar ago | 0

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Answered

How od i generate random numbers whose sum is constant?

Check this out https://uk.mathworks.com/matlabcentral/fileexchange/9700-random-vectors-with-fixed-sum

How od i generate random numbers whose sum is constant?

Check this out https://uk.mathworks.com/matlabcentral/fileexchange/9700-random-vectors-with-fixed-sum

28 dagar ago | 1

Answered

isqnonlin: compute part of objective function outside of matlab

"The gradient vector of the objective function res with respect to the parameters p is calculated like this: d(res)/d(p) = 2*(s...

isqnonlin: compute part of objective function outside of matlab

"The gradient vector of the objective function res with respect to the parameters p is calculated like this: d(res)/d(p) = 2*(s...

29 dagar ago | 0

Answered

What is the best function of the following shape?

Try this: xmin = 1; xmax = 3; pp = struct('form','pp',... 'breaks',[-1e-100 0 1 inf],... 'coefs',[0 0 0 0 0 0;6,-...

What is the best function of the following shape?

Try this: xmin = 1; xmax = 3; pp = struct('form','pp',... 'breaks',[-1e-100 0 1 inf],... 'coefs',[0 0 0 0 0 0;6,-...

30 dagar ago | 1

Answered

need general coding/ command to separate matrix data

Try this: % Fake data finalmatrix=sortrows(randi(10,30,3),1) y = finalmatrix(:,1); n=diff(find([true; diff(y)~=0; true])) ...

need general coding/ command to separate matrix data

Try this: % Fake data finalmatrix=sortrows(randi(10,30,3),1) y = finalmatrix(:,1); n=diff(find([true; diff(y)~=0; true])) ...

ungefär en månad ago | 0

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Answered

Replacing Arrays and Matrices

IMO nothing hurts of using same variable name for different things. But my experience tell me that is a bad habit of programmin...

Replacing Arrays and Matrices

IMO nothing hurts of using same variable name for different things. But my experience tell me that is a bad habit of programmin...

ungefär en månad ago | 1

Answered

where the jump of the phase function happen?

angle(z) is discontinue at the half line { y=0; x<=0, z=x+1i*y }. The phase jumps from -pi for imaginary part y < 0 to +pi for ...

where the jump of the phase function happen?

angle(z) is discontinue at the half line { y=0; x<=0, z=x+1i*y }. The phase jumps from -pi for imaginary part y < 0 to +pi for ...

ungefär en månad ago | 0

Answered

How can I integrate a function related to the modified bessel function of the first kind?

You can also "vectorize" distribution_func by applying arrayfun beta = 5 ; sigma = 1.4/3; integ_func = @(theta,x) x./sigma.^2...

How can I integrate a function related to the modified bessel function of the first kind?

You can also "vectorize" distribution_func by applying arrayfun beta = 5 ; sigma = 1.4/3; integ_func = @(theta,x) x./sigma.^2...

ungefär en månad ago | 0

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Answered

adding counts of ordered pairs

A1=[1 4 3; 3 5 1; 12 4 7; 13 5 2; 14 1 1]; A2=[1 5 1; 13 5 1; 13 7 3; 14 1 5]; A12=[A1; A...

adding counts of ordered pairs

A1=[1 4 3; 3 5 1; 12 4 7; 13 5 2; 14 1 1]; A2=[1 5 1; 13 5 1; 13 7 3; 14 1 5]; A12=[A1; A...

ungefär en månad ago | 1

Answered

How to simulate Poisson Distribution Process?

Another way based on exponetial distribution, which is the time between 2 events % Generate n random integers follow Poisson wi...

How to simulate Poisson Distribution Process?

Another way based on exponetial distribution, which is the time between 2 events % Generate n random integers follow Poisson wi...

ungefär en månad ago | 0

Answered

Parallel rank calculation for sparse matrices -- suggestions?

For thin and tall sparse matrix A of size (m x n), m>>n and n in the order of 1000s, it might be possible to compute the rank us...

Parallel rank calculation for sparse matrices -- suggestions?

For thin and tall sparse matrix A of size (m x n), m>>n and n in the order of 1000s, it might be possible to compute the rank us...

ungefär en månad ago | 0

Answered

How to simulate Poisson Distribution Process?

If you don't have staistics toolbox % Generate n random integers follow Poisson with parameter (==mean) lambda lambda=3; n =...

How to simulate Poisson Distribution Process?

If you don't have staistics toolbox % Generate n random integers follow Poisson with parameter (==mean) lambda lambda=3; n =...

ungefär en månad ago | 1

Answered

Fitting a monotonically increasing spline function

One way is to use my https://uk.mathworks.com/matlabcentral/fileexchange/25872-free-knot-spline-approximation x = [0., 0.75, ...

Fitting a monotonically increasing spline function

One way is to use my https://uk.mathworks.com/matlabcentral/fileexchange/25872-free-knot-spline-approximation x = [0., 0.75, ...

ungefär en månad ago | 1

| accepted

Answered

How to constrain the resulting equation from a polynomial surface fit to a positive range?

This is implementation of Torsen's idea data=readmatrix('https://www.mathworks.com/matlabcentral/answers/uploaded_files/1116665...

How to constrain the resulting equation from a polynomial surface fit to a positive range?

This is implementation of Torsen's idea data=readmatrix('https://www.mathworks.com/matlabcentral/answers/uploaded_files/1116665...

ungefär en månad ago | 0

Answered

Using linprog but it's only returning 'Optimal solution found' with no feasible solution?

It looks solution is correct to me. Note that the Aeq = [] meaning you don"t supply equality constraint, so I need to check for...

Using linprog but it's only returning 'Optimal solution found' with no feasible solution?

It looks solution is correct to me. Note that the Aeq = [] meaning you don"t supply equality constraint, so I need to check for...

ungefär en månad ago | 0

Answered

Error in finding the angle between three points using atan2

142.9 degree seem right to be. If you don't make the same aspect ratio of x and y with axis equal, angles are deformed on your s...

Error in finding the angle between three points using atan2

142.9 degree seem right to be. If you don't make the same aspect ratio of x and y with axis equal, angles are deformed on your s...

ungefär en månad ago | 0

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