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Proof that sum of all positive integers is -1/12
This has nothing to do with MATLAB and numerical sums. You can pretty much get any answer you want by manipulating divergent se...

plus de 6 ans il y a | 3

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Using ode45 to solve odes from a matrix
F = [-f1 f1 0 0; 0 -f2 f2 0; 0 0 -f3 f3; v 0 0 -v].'; f = @(t,y) F * y;

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Differentiating within a for loop
I assume by "three times" what was meant was diffferentiate the results iteratively three times, not differentiate the original ...

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Coding fibonacci without using fibonacci matlab code
Hint: The fprintf( ) function will automatically wrap around if you have too many variables than the format string allows for. E...

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How do I fill a matrix of 1s and 0s with sequential numbers
nnza = nnz(A); nnzb = nnz(B); At = A'; Bt = B'; At(logical(At)) = 1:nnza; Bt(logical(Bt)) = (nnza+1):(nnza+nnzb); Aresult ...

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How to quickly find the column index of the last non-zero element in all rows in a sparse matrix?
You can use a mex routine for this and avoid all temporary data copies. E.g., a direct approach: /* File: find_last_nz.c *...

plus de 6 ans il y a | 3

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How can I find the difference between values in an array with an index spacing of 2?
Hint: Look at x(1:2:end) and x(2:2:end). If x has an even number of elements, you could reshape(x,2,[]) and then look at some ...

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How can I print the result of a function using fprintf? (matrix and string!)
When comparing strings, it is not a good idea to use the == operator, which is an element-wise operator. Instead, use a string ...

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Voltage of a capacitor as a function of time
Maybe the function you want is cumsum( ) instead of sum( )?

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Pythagorean Triples with Loops
E.g., an outline % (1) insert code here to ask for the largest value n for a=1:n for b=a:n for c=b:n ...

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Describing the motion of a composite body using system of second order differential equations
In this line: xy(2)=x(2)*x(2)*tan(x(1))-xy(4)*4*sec(x(1)); you are using xy(4) before it is defined. That is, you have t'' d...

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Quaterion Creation In Simulink
See these posts for discussions of the MATLAB quaternion convention: https://www.mathworks.com/matlabcentral/answers/352465-wha...

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rotate acceleration vector using rotation matrix
You can use a loop, e.g. acc = your 940x3 matrix r = your 3x3x940 array result = zeros(size(acc)); for k=1:size(acc,1) ...

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C MEX file issue in for loop
These lines do not do what you think they do: double* data : ... data[j,i] ... From your code it is obvious that you thi...

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Why 0.35 divide 0.001 return double, and 0.34 divide 0.001 return int.
Welcome to the world of floating point arithmetic. In one case, the result is 340 exactly so it prints without any trailing 0's...

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A soumis

SHAREDCHILD creates a shared data copy of contiguous subset
SHAREDCHILD creates a shared data copy of a contiguous subsection of an existing variable

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Stop value in loop for repeating
Not sure if you need the numbers to be different or not. Either this: for k=i:length(myprime) or this for k=i+1:length(myprim...

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Simplifying complex multiplications by means of polar coordinates
It looks like your accumulation is trying to sum polar coordinates. You can't do that. I.e., if you have (r1,theta1) and (r2,t...

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How to put a name on each double variable in a cell array"
You could have an associated cell array for the file names. E.g., fnames{i,j} = fn;

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2nd Order ODE
For a numerical solution, you could try this function: https://www.mathworks.com/help/matlab/ref/bvp4c.html

plus de 6 ans il y a | 1

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Converting Parameter from mxArray to a C-Style String
If it is a single quote ' ' char array, then just char *cp; cp = mxArrayToString(prhs[2]); If it is a double quote " " string...

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HOW to create 4D array and 3D array
Fortran allows negative and 0 indexing, but MATLAB does not. There is no double class equivalent of this in MATLAB. You would ...

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How to combine matrices
This sounds like a job for cell arrays. E.g., read here: https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-va...

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Adding a vector in a system of differential equations
One way is to create a function handle to pass in the extra parameters. E.g., function [output] = DiffEquations(time,init,iapp...

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Index in position 1 is invalid. Array indices must be positive integers or logical values?
If you are trying to create an anonymous function, the syntax is: f = @(u,v) (sin((B*Lx)*u)/((B*Lx/2)*u))*(sin((B*Ly)*v)/((B*Ly...

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Question about using randperm in a loop
If you want each number in the matrix to be unique, then don't call randperm( ) by row because that will not guarantee uniquenes...

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Difficulties with interpreting and use of @ sign
You don't have to use all of the input arguments. The following is fine which ignores t: f = @(t,y)((y-1)*(y-2)); I.e., if y...

plus de 6 ans il y a | 2

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Speeding bitand / bitshift and type conversion
Try this: DataWord16 = typecast(DataWord1,'uint16'); % shared data copy for later versions of MATLAB Var1 = DataWord16(1:2:end...

plus de 6 ans il y a | 2

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Is there a fast way to get subsequences of a matrix with indices from a vector?
Unfortunately, you have the worst memory layout of your data for this. Each sub-matrix is scattered throughout memory so the ca...

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Given a matrix A^n. Comparing normal multiplication versus Diagonalization. I expect the former to be faster but its not in my case
Well, the timings didn't meet your expectations. Why would you expect A*A to be slower than doing a full eig calculation follow...

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