Professional Interests: computational physics, applied mathematics

Answered

How to fit to an infinite series function?

An iterative solution instead of the symbolic one can be more productive this case, like this one x=[0 5 10 15 20 30 45 60 75 9...

How to fit to an infinite series function?

An iterative solution instead of the symbolic one can be more productive this case, like this one x=[0 5 10 15 20 30 45 60 75 9...

alrededor de 1 mes ago | 0

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Answered

How to average columns of matrix without loop?

reshape(mean(reshape(A',n,[]))',size(A,2)/n,[])'

How to average columns of matrix without loop?

reshape(mean(reshape(A',n,[]))',size(A,2)/n,[])'

alrededor de 2 meses ago | 0

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Answered

When i try this sym('x')^y i get an error message

You cannot compute this directly because the integers are larger than matlab is able to treat. You can try b = sym(log10(18008...

When i try this sym('x')^y i get an error message

You cannot compute this directly because the integers are larger than matlab is able to treat. You can try b = sym(log10(18008...

3 meses ago | 1

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,...

4 meses 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...

4 meses 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))...

5 meses 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

5 meses 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 ...

5 meses 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)...

5 meses 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...

7 meses 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)

7 meses 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...

7 meses 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.

7 meses 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)

7 meses 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 ...

7 meses 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...

7 meses 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 ...

7 meses 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...

7 meses 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...

7 meses 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...

7 meses 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...

8 meses 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...

8 meses 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...

8 meses 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...

8 meses 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

8 meses 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)

9 meses 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

11 meses ago | 2