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Vladimir Sovkov


Last seen: 5 dagen ago

St. Petersburg State University

55 total contributions since 2014

Professional Interests: computational physics, applied mathematics

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Answered
How to Convert 3d matrix to row matrix???
a=rand(2,2,2) % a sample 3D matrix a b=a(:)' % is turned to the 1D row matrix b

ongeveer 2 maanden ago | 2

Answered
Plot the trapeoidal waveform using given equations
syms theta y=piecewise(... 0<=theta<2*pi/3,1,... 2*pi/3<=theta<pi,(1-6/pi*(theta-2*pi/3)),... pi<=theta<5*pi/3,-...

3 maanden ago | 0

Answered
How to draw an ellipse
The code discussed at https://www.mathworks.com/matlabcentral/answers/497966-how-to-find-the-vertical-height-of-an-ellipse-y-axi...

4 maanden ago | 0

Answered
Eigenvalues corresponds to eigenvectors
Absolutely standard: L(k,k) ~ V(:,k). You can check it with the code: for k=1:size(h,1) disp(strcat('k=',num2str(k),'; h*v-la...

4 maanden ago | 0

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Answered
Subs Command for Multivariable Function
If e^ is the exponent and if you want to estimate the result numerically (from the question it is not quite clear what you want)...

4 maanden ago | 0

Answered
Partial least-squares regression evalutaion
The equation considered in PLS of Matlab is rather Y = X(:,:)*B(2:end,:) + repmat( B(1,:),n,1 ) + E, where: X is an n-by-...

4 maanden ago | 0

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Answered
Normalization of complex eigenvector
You probably want V(:,1) = V(:,1)/norm(V(:,1)); Besides, if your theta and phi are supposed to be real, the overall computatio...

4 maanden ago | 0

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Answered
Eigenvector without calling eigenvalues
This is not an error but a warning that you do not use the eigenvalues, which influences nothing. If you want to avoid it, subst...

4 maanden ago | 0

Answered
Can I check if factored and expanded polynomial forms are equal?
simplify((w^2-k^2) - (w+k)*(w-k)) ans = 0 expand((w+k)*(w-k)) ans = w^2 - k^2 factor(w^2-k^2) ans = [ -1, k - w...

4 maanden ago | 0

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Answered
How to call some object handle from opening function of figure?
u0=findobj('Tag','lst1','Style','listbox','Parent',gcf); % search for all the object properties you used to identify it set(u0,...

4 maanden ago | 0

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Submitted


Wigner 3j-6j-9j
Wigner 3j-, 6j-, 9j-symbols

4 maanden ago | 10 downloads |

Answered
Find orthogonal complement for given matrix
B=null(A'); The matrix transposing is important!

4 maanden ago | 1

| accepted

Answered
How can I write a loop, which can make the parameter "V" change with a cyclic variable "i"?
Use Matlab functions "strcat" and "num2str" within a loop.

4 maanden ago | 0

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Answered
How do I calculate acceleration with velocity and the code given?
% sample data t=0:0.1:10; % time x=3+2*t+t.^2; % coordinate [t,ind]=sort(t); % in a case time is not in an ascending order ...

4 maanden ago | 0

Answered
How to assign numbers to letters of the alphabet. Ex. A/a=1 B/b=2
The ASCII codes can be found with the function double double('A'); 65 If you want to get its ordinal number in the alphabet, ...

5 maanden ago | 0

Answered
How to sum columns of a matrix in MATLAB in specified number of columns?
B=squeeze( sum( reshape(A,size(A,1),10,[]) ,2) );

5 maanden ago | 0

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Answered
Create a gaussian from x values
L=20; V = linspace(0,L,301); sigma = L/20; T0 = exp(-((V-mean(V))/sigma).^2/2); plot(V,T0);

5 maanden ago | 1

| accepted

Answered
extract a double array to multiple arrays
b1=aa(1:4:end); b2=aa(2:4:end); b3=aa(3:4:end); b4=aa(4:4:end);

5 maanden ago | 1

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Answered
Importing Latex Code into Matlab Scripts
In live script, go to \insert\Equation\Latex equation or just press Cntrl+Shift+L or type your Latex equation embraced by $ symb...

5 maanden ago | 0

Submitted


DigBit
Image Digitizer: Turn your scanned plots to the numeric form

5 maanden ago | 1 download |

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Answered
How can I calculate the integral2 using sum of prod?
symprod does not support the element-wise multiplication, which is needed for integral2. You sholuld probably define your fun v...

5 maanden ago | 1

| accepted

Answered
sorting 2 array based on elements of other array
[A,ind]=sort(A); B=B(ind);

5 maanden ago | 0

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Answered
How to find the maximum distance between two curves?
(1) Specify, what do you mean by the distance between curves. If this is the distance between any points of them, a special (tho...

5 maanden ago | 2

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Answered
New to Matlab- How to import a text file for analysis that contains numbers and characters?
If you need it only once (or few times), use the Import utility of Matlab (Home\Import Data - a green downward arrow); chose the...

5 maanden ago | 0

Answered
help speeding up an incrementing loop
At the first glance, you can replace numerator=0; for k = 1:n_trc numerator = nume...

5 maanden ago | 0

Answered
How to find the vertical height of an ellipse/y axis length of ellipse.
In fact, the height and the width of an ellipse can be easily and more accurately found analytically. Here is Matlab program rea...

5 maanden ago | 1

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Answered
How to expand the Gaussian Kernel into series of eigenfunctions?
Fitst of all, you should specify --nothing can be done with an arbtrary function. Then, you can try to calculate the integrals a...

5 maanden ago | 1

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Answered
Turn function to zero when it reach specific value.
x = linspace (0,180,1800); y = 1. * ((exp (-0.01 .* x)) .* (sin (x)-(x .* cos (x / 2)))); Pu = 30; y(find(y>=Pu,1):end)=0; ...

5 maanden ago | 0

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Answered
How to show part of a nested structure as a vector?
sn='seine_1'; % sn=fieldnames(all_seines); % sn=sn{1}; nm=fieldnames(all_seines.(sn)); N=numel(nm); A=zeros(N,1); for k=...

6 maanden ago | 0

Answered
Values over 1000 use e
read matlab help on the "format" command. try "format longg".

6 maanden ago | 0

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