Professional Interests: computational physics, applied mathematics

Answered

How to plot step functions in Matlab

syms x; y=piecewise(x<0,0, 0<=x<2*pi,exp(-x).*cos(x), x>=2*pi,2*exp(-x).*cos(x)); t=linspace(-pi,4*pi,1000); plot(t,subs(y,x,...

How to plot step functions in Matlab

syms x; y=piecewise(x<0,0, 0<=x<2*pi,exp(-x).*cos(x), x>=2*pi,2*exp(-x).*cos(x)); t=linspace(-pi,4*pi,1000); plot(t,subs(y,x,...

ongeveer een maand ago | 0

Answered

Adding or subtracting the same number

n=4; % array length x=zeros(1,n); % sample array d=0.4; % value to be added/subtracted k=rand(1,n); % uniformly random number...

Adding or subtracting the same number

n=4; % array length x=zeros(1,n); % sample array d=0.4; % value to be added/subtracted k=rand(1,n); % uniformly random number...

ongeveer een maand ago | 1

Answered

How to plot complicated exponential function 4.82 (1 + 0.35 e^ −4.07t ) / (1 − 0.35 e^−4.07t) on matlab

Use the element-wise division when computing y: y = ((4.8184) * (1 + 0.3497.*exp(-4.0719.*x))) ./ (1 - 0.3497.*exp(-4.0719.*x))...

How to plot complicated exponential function 4.82 (1 + 0.35 e^ −4.07t ) / (1 − 0.35 e^−4.07t) on matlab

Use the element-wise division when computing y: y = ((4.8184) * (1 + 0.3497.*exp(-4.0719.*x))) ./ (1 - 0.3497.*exp(-4.0719.*x))...

ongeveer een maand ago | 1

Answered

make different numbers with the same digits

x=1342; y=str2num(sort(num2str(x),'ascend')); % smaller z=str2num(sort(num2str(x),'descend')); % bigger

make different numbers with the same digits

x=1342; y=str2num(sort(num2str(x),'ascend')); % smaller z=str2num(sort(num2str(x),'descend')); % bigger

ongeveer een maand ago | 0

Answered

is it possible to write a code that examine and analyze that a data in vector having 100 values, so recognize that if one or two very high as compare to other data?

This is known as the problem of locating outliers. Various approaches were proposed. E.g., the one based on the median absolute ...

is it possible to write a code that examine and analyze that a data in vector having 100 values, so recognize that if one or two very high as compare to other data?

This is known as the problem of locating outliers. Various approaches were proposed. E.g., the one based on the median absolute ...

ongeveer 2 maanden ago | 0

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Answered

flip the sign at zero crossing point

Data1 = [1,0,1,1,0,1,1,0,0,1,0,1,0]; k=find(~Data1); if ~isempty(k) if k(end)<numel(Data1) k(end+1)=numel(Data1)...

flip the sign at zero crossing point

Data1 = [1,0,1,1,0,1,1,0,0,1,0,1,0]; k=find(~Data1); if ~isempty(k) if k(end)<numel(Data1) k(end+1)=numel(Data1)...

ongeveer 2 maanden ago | 0

Answered

Issue with 'for' loop - trying to iterate through and change certain values to 0 in array

If the equality must be exact, just x_results(x_results==.3095)=0; and nothing else (sometimes can produce an incorrect result...

Issue with 'for' loop - trying to iterate through and change certain values to 0 in array

If the equality must be exact, just x_results(x_results==.3095)=0; and nothing else (sometimes can produce an incorrect result...

3 maanden ago | 0

Answered

How can I create a script that calculates this combinatorial?

C=nchoosek(n,r)

How can I create a script that calculates this combinatorial?

C=nchoosek(n,r)

3 maanden ago | 0

Answered

Specify eigenvector for eigs

Matlab documentation: 'StartVector' — Initial starting vector random vector (default) | vector Initial starting vector, spe...

Specify eigenvector for eigs

Matlab documentation: 'StartVector' — Initial starting vector random vector (default) | vector Initial starting vector, spe...

3 maanden ago | 0

Answered

How to "wrap text" on pushbutton string?

Use the cell array with entries containing text fragments to be shown in separate strings.

How to "wrap text" on pushbutton string?

Use the cell array with entries containing text fragments to be shown in separate strings.

4 maanden ago | 0

Answered

how to implement the algorithm for approximating Cosine using the Taylor series

syms theta n=4; taylor(cos(theta),'Order',n)

how to implement the algorithm for approximating Cosine using the Taylor series

syms theta n=4; taylor(cos(theta),'Order',n)

4 maanden ago | 0

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Answered

Is there any way to accelerate the solving of a series of large sparse positive definite linear equations "Ax=b" with same "A" and different "b"?

It depends... Besides inv(A), you can try A\eye(n), pinv(A)--all of them are equivalent for a well-conditioned A and different ...

Is there any way to accelerate the solving of a series of large sparse positive definite linear equations "Ax=b" with same "A" and different "b"?

It depends... Besides inv(A), you can try A\eye(n), pinv(A)--all of them are equivalent for a well-conditioned A and different ...

4 maanden ago | 0

Answered

Is there any method to calculate the inverse of matrix which changed a few values?

I am not sure how much profitable it is numerically, but the Sherman Morrison theorem can be a way, see https://en.wikipedia.org...

Is there any method to calculate the inverse of matrix which changed a few values?

I am not sure how much profitable it is numerically, but the Sherman Morrison theorem can be a way, see https://en.wikipedia.org...

4 maanden ago | 1

Answered

What does ''all'' mean in M = min(A, []. ''all'') ?

All this is fairly well described in the matlab documentation. min(min(A)) and min(A, [], ''all'') are equivalent for 1D and 2D ...

What does ''all'' mean in M = min(A, []. ''all'') ?

All this is fairly well described in the matlab documentation. min(min(A)) and min(A, [], ''all'') are equivalent for 1D and 2D ...

4 maanden ago | 0

Answered

If I have multiple function, then how can I get the function of min(fun1,fun2,fun3,...)?

xmin=min([R1(x(:)');R2(x(:)');...]); % to get a correct result, the argument must be a row-vector: x(:)' turns any input array t...

If I have multiple function, then how can I get the function of min(fun1,fun2,fun3,...)?

xmin=min([R1(x(:)');R2(x(:)');...]); % to get a correct result, the argument must be a row-vector: x(:)' turns any input array t...

4 maanden ago | 0

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Answered

Is there a bug in the if function

This is not a bug in the if function but an artefact of the rounding of the matlab bit-wise arithmetics. To avoid this effect, s...

Is there a bug in the if function

This is not a bug in the if function but an artefact of the rounding of the matlab bit-wise arithmetics. To avoid this effect, s...

4 maanden ago | 0

Answered

Angle between two lines in frontal plane

If, as it looks in the figure, (...Y) are the verticle coordinates and (...Z) are the horizontal coordinates, then the basic geo...

Angle between two lines in frontal plane

If, as it looks in the figure, (...Y) are the verticle coordinates and (...Z) are the horizontal coordinates, then the basic geo...

4 maanden ago | 1

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Answered

solve function give a wrong solution

syms x solv = double(solve( (1+x/12)^12 == 1.02)) There are many solutions. The one you are interested in is rather 0.01981897...

solve function give a wrong solution

syms x solv = double(solve( (1+x/12)^12 == 1.02)) There are many solutions. The one you are interested in is rather 0.01981897...

4 maanden ago | 0

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Answered

How to see the current value of the variable in "fminsearch" optimization?

optimset('Display','iter'); From Matlab documentation: 'Display' — Level of display 'notify' (default) | 'final' | 'off' | 'n...

How to see the current value of the variable in "fminsearch" optimization?

optimset('Display','iter'); From Matlab documentation: 'Display' — Level of display 'notify' (default) | 'final' | 'off' | 'n...

4 maanden ago | 0

Answered

showing the distance between the two plots on two curves at regular intervals on the same plot

t=0:0.2:10; % avoid loops wherenever possible, use element-wise operations instead x=t.^2; y=0.5*x+10; % the same as "y=0.5*t...

showing the distance between the two plots on two curves at regular intervals on the same plot

t=0:0.2:10; % avoid loops wherenever possible, use element-wise operations instead x=t.^2; y=0.5*x+10; % the same as "y=0.5*t...

5 maanden ago | 0

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Answered

Writing into .txt file

T = [v angle_random]; % this is if you want a 2-column file save('random_cylind.txt','T','-ascii','-double'); % explore availab...

Writing into .txt file

T = [v angle_random]; % this is if you want a 2-column file save('random_cylind.txt','T','-ascii','-double'); % explore availab...

5 maanden ago | 0

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Answered

Debugging using external editor

https://www.mathworks.com/help/matlab/matlab_external/debugging-on-microsoft-windows-platforms.html

Debugging using external editor

https://www.mathworks.com/help/matlab/matlab_external/debugging-on-microsoft-windows-platforms.html

5 maanden ago | 0

Answered

How do I record the location of a specific value in a set of data?

a=[0 0 0 0 1 0 1 0 0]; k=find(a==1,1)

How do I record the location of a specific value in a set of data?

a=[0 0 0 0 1 0 1 0 0]; k=find(a==1,1)

6 maanden ago | 0

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

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

8 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,-...

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,-...

9 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...

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...

10 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...

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...

10 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)...

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)...

10 maanden ago | 0