Risposto
two body problem using ode45
The RK methods don't match up well with the orbit DE problem because the integration errors tend to be systematic (e.g., always ...

oltre 6 anni fa | 1

Risposto
Duffing Oscillator issue. "Keep getting Unable to perform assignment because the left and right sides have a different number of elements."
t is a vector, so your cos(omega*t) is a vector. You need to use cos(omega*t(n)) there.

oltre 6 anni fa | 0

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double integration of acceleration data with offset
You put a constant offset into the acceleration, not the position. The result of double integrating a constant is going to be a ...

oltre 6 anni fa | 0

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Need help verifying code for Euler MEthod, RK2 and RK4
Your biggest problem is that you don't have the differential equations coded correctly. And the main cause of that is because y...

oltre 6 anni fa | 0

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Risposto
Numerically Integrating the differential equation below?
You've got two 2nd order DE's, so that means you have a 4th order system (2x2=4) and thus your state vector will contain four el...

oltre 6 anni fa | 0

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Risposto
Generate all possible combinations for the column vectors of a matrix
E.g., >> B = [1;2]; >> n = 3; >> Bcell = arrayfun(@(k)B,1:n,'uni',false); >> C = allcomb(Bcell{:}) Warning: NARGCHK will be...

oltre 6 anni fa | 1

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Risposto
Removing single quotations from a character array
Your answer does not include the bounding single quotation marks ... that is just a display artifact for how MATLAB prints chara...

oltre 6 anni fa | 0

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Help, I don't understand why the output multiplies everything by 1.0e+03
That's just the default way that MATLAB displays the numbers, rather that tacking e+03 to each number individually. You could u...

oltre 6 anni fa | 0

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Risposto
Error trying to solve 2 Second ODE
Just looking at func.m, it appears you pass in a 4-element x vector, but you only return a 2-element a vector. You need to retu...

oltre 6 anni fa | 0

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vpa doesn't seem to work
You are passing a double into vpa( ), so your precision is lost before you even call it. You could pass in a string instead: n ...

oltre 6 anni fa | 1

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Risposto
A function to find prime number
Your function doesn't return anything, so when you try to use its output you get an error. Change this: function isPrime(numbe...

oltre 6 anni fa | 0

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Risposto
Rolling all six numbers on a six sided die
This: v = zeros(1,NToys); NRolls = 0; needs to be inside your Trial loop so that it resets for each trial. A simpler way to ...

oltre 6 anni fa | 0

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Need help Euler Method
The fundamental thing you are doing wrong is that you don't have the proper size state vector. For a 1st order equation, the st...

oltre 6 anni fa | 0

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How can I add values of an array as an input into the ode45 function ?
What is the size of I? What is the DE you are solving? Maybe just dropping the (t) will work: dydt= (-I/(3600*Q)); Or maybe ...

oltre 6 anni fa | 0

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Risposto
double differentiation and double integration of sine wave
"... when differentiating my position to get velocity and acclereation i did work out all three of them by hand, quite sure it i...

oltre 6 anni fa | 0

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Comparison of two Vektors with different size to find variables
E.g., x = ismember(b(:,1:2),a(:,1:2),'rows'); c = b(x,:); Depending on how the times were constructed, you might need to use ...

oltre 6 anni fa | 0

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Risposto
How to transfer parameter between C and fortran
Maybe the Fortran compiler settings are compiling the default integer as 8-byte integers. Try forcing the Fortran to use 4-byte ...

oltre 6 anni fa | 0

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How to sort a matrix in a random order
E.g., >> x = reshape(1:24,4,6) x = 1 5 9 13 17 21 2 6 10 14 18 22 3 7 ...

oltre 6 anni fa | 0

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Risposto
can someone help me to solve this error (This statement is not inside any function. (It follows the END that terminates the definition of the function "RK4".)
Looks like your plot( etc ) and legend( etc ) lines are stuck inbetween two functions. Did you intend them to be inside a scrip...

oltre 6 anni fa | 0

Risposto
making array in for loop
Maybe prior to the loop define Alignment as a cell array to hold your results: Alignment = cell(10000,1);

oltre 6 anni fa | 0

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Risposto
Why is my function generating a vector? Please help?
A uniform random number between a and b is: u = a + rand*(b-a) Generate two of these with a = -0.05 and b = 0.05 and then do t...

oltre 6 anni fa | 0

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Can someone explain the concept of B= null(A) in simple words?
The columns of B form basis vectors for the "null space" of A. Any linear combination of the B columns, when multiplied by A, w...

oltre 6 anni fa | 1

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Unable to perform assignment because the size of the left side is 1-by-1 and the size of the right side is 5-by-1.
Looks like Cd and rho are vectors. So the result of those calculations on the right hand side will be vectors. But you are tryin...

oltre 6 anni fa | 0

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Risposto
What can I use instead of VPA?
See the following FEX submissions by John D'Errico: https://www.mathworks.com/matlabcentral/fileexchange/36534-hpf-a-big-decima...

oltre 6 anni fa | 1

Risposto
Two equal datetime values showing as unequal when compared?
This is often just a display issue. E.g., >> s = datetime(2017,3,24,9,5,0.1) s = 24-Mar-2017 09:05:00 >> t = datetime(20...

oltre 6 anni fa | 0

Risposto
How can I multiply square submatrices more efficiently?
Here is the naive mex code. Could probably be made faster by doing the for-loop in parallel or trying to optimize cache hits, b...

oltre 6 anni fa | 1

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Risposto
big difference in execution time in approximately the same code
The matrix multiply operator * in MATLAB calls highly optimized compiled BLAS library code in the background. The BLAS library ...

oltre 6 anni fa | 2

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This is a question from numerical methods asking to explain what the code does for 12 marks.
https://en.wikipedia.org/wiki/Newton%27s_method

oltre 6 anni fa | 0

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Risposto
how to use passing by value and passing by reference
In the background, MATLAB effectively passes all variables into functions as shared data copies. This has the same effect as pas...

oltre 6 anni fa | 0

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matrix dimensions must agree error
Well, tau is only two elements and w is a lot more than that, so you can't multiply them element-wise like you are attempting to...

oltre 6 anni fa | 0

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