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How to multiply higher order matrices?
You may need to permute your arrays first to get your desired 2D slices in the first two dimensions. A = whatever B = whatever...

alrededor de 5 años hace | 2

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Using matrix to index another matrix?
Does this do what you want: x = sub2ind(size(B),(1:size(A,1))',A(:,1),A(:,2),A(:,3)); Output = B(x);

alrededor de 5 años hace | 0

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Equivalent of c++'s NULL or python' s None in MATLAB
This will probably depend on how these are used downstream in your code and whether you have arrays of them to deal with. If th...

alrededor de 5 años hace | 1

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X Y Z angles of a D20 (icosahedron) for gravity projection
If you have the 3D normal vectors, then all you need to do is take the dot product between them and the "flat" face normal vecto...

alrededor de 5 años hace | 1

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modify a row of an array within a function
This can sometimes be done inplace depending on how you write the function and how you call the function. One requirement is yo...

alrededor de 5 años hace | 0

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Operator '-' is not supported for operands of type 'function_handle'.
You are using u as both an input argument and a global function handle function A3 = odeFun(t, u) <-- input argument global R...

alrededor de 5 años hace | 0

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Solve a system of 3 second order ODE
You will need to change your scalar equations to vector equations, and you will need to change your derivative function to a vec...

alrededor de 5 años hace | 0

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Need to speed up the generation of random numbers.
You could over generate a large matrix and then pick off the number of elements you need later. E.g., C = rand([5 size(A)]); T...

alrededor de 5 años hace | 0

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How do i create a large matrix with a formula?
N = 1000; a = 2 * pi * f * T * (0:N-1)'; x = [cos(a) -sin(a)];

alrededor de 5 años hace | 1

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Matrix multiplication to get covariance matrix
@Tintin Milou MATLAB variables do not have a "symmetric" attribute flag that I know of. Just because you create a variable that...

alrededor de 5 años hace | 0

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Why can't complex integer arithmetic be done?
I think the main reason for disallowing integer array arithmetic in MATLAB is because of the ambiguity caused by the max(min( ))...

alrededor de 5 años hace | 1

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How can I split C/C++ Code in multiple files and still use MEX
Use the -c option to compile the B and C stuff to produce only object files without any linking: mex -c B.c C.c Then compile y...

alrededor de 5 años hace | 1

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Matrix multiplication. Trying to get scalar solution
Those should be matrix multiples, not element-wise multiplies. Remove the dots. E.g., top=nMode * M * u0; bot=nMode * M * nM...

alrededor de 5 años hace | 0

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Adapt RK4 ODE Solver from first order to 2nd order
Try this for starters yt = zeros(numel(y0),length(h:tfinal)); %Memory Allocation And then maybe this is what is intended for i...

alrededor de 5 años hace | 0

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Error using vertcat Dimensions of arrays being concatenated are not consistent.
You have a mismatch in the number of arguments. E.g., this [V,y] = ode45(@(~,y) fun(del_h1,del_cp1,cp1),Vspan,y0); should be ...

alrededor de 5 años hace | 0

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Replacing matrix n column values
E.g., temp = A(:,70:80); temp(temp<0) = 0; A(:,70:80) = temp;

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Solving an overdetermined system of linear equations
Since you can simply plug in those values to verify that they satisfy all four equations, the conclusion would be that you have ...

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How to create a cell array with binary numbers?
Your pop variable has 1000x11 = 11000 elements. Your for-loop only assigns values to 1000 of those elements (the first column)....

alrededor de 5 años hace | 0

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Vector sum of forces
sqrt(sum(F.*F,2))

alrededor de 5 años hace | 0

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invalid use of operator
You are missing a ( after the second "if", and you are missing an "end" statement. That being said, my suggestion would be to u...

alrededor de 5 años hace | 0

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Need Help Solving Two Coupled ODEs
The derivative function needs to have the input arguments specified. In your current code above, you have no inputs specified. ...

alrededor de 5 años hace | 0

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Versions of Euler Methods
methodA has a fundamental flaw: y(i+1) = y(i)+ h*func( t(i) + h/2, (y(i)+y(i+1))/2 ); You can't use y(i+1) on the right hand s...

alrededor de 5 años hace | 1

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Problem with matrix differential equation resolve in Matlab with ode45
Normally I would have expected ode45( ) to pass q as a 4x1 column vector. Also, I don't see anything in your code solving for q...

alrededor de 5 años hace | 0

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Question regarding quaternion conventions; particularly with respect to point vs frame rotations
See this post for comments regarding "point" vs "frame" convention: https://www.mathworks.com/matlabcentral/answers/524471-what...

alrededor de 5 años hace | 0

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Using vectorization to shorten run time
E.g., [P,D] = meshgrid(p,d); % generate all possible combinations X = [P(:) D(:)]; % combine them into side-by-side column vec...

alrededor de 5 años hace | 1

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why does dimension of input variable change in ode45
The dimension changes to a column vector because that is the way ode45( ) operates. Your derivative function needs to be able t...

alrededor de 5 años hace | 1

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Maatlab crash with .mex function
I had to make some assumptions about how the matrix data areas are supposed to be loaded. We can try this first to see if these...

alrededor de 5 años hace | 0

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How to calculate standard deviation in double for loop?
The short answer is don't do that. This style of programming has many problems. See this link for alternatives: https://www.m...

alrededor de 5 años hace | 0

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Add row to an empty array if a condition is fulfilled
No need for an explicit loop. Just use logical indexing: result = m(strcmp(m(:,3),'A'),:);

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reproduce random numbers for the third dimension
If you don't want the random numbers to change from iteration to iteration, then don't regenerate them inside the loop. Calcula...

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