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euler's method
Your code does not have enough states. You have a 2nd order ODE (the highest derivative present is 2), so the state vector need...

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Sum of series in matlab
You could use a simple matrix multiply for this (it looks like the x is the first row and the y is the second row): A = R(1,1:2...

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How does vrrotvec calculate rotation?
It is a simple algorithm that uses the cross product for the axis (normalized), and the dot product is used to calculate the ang...

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How do I make a condition statement for an element that presents in two different arrays but is at the wrong position? This also applies to more than one elements
Assuming you have already made the check for the correct number in the correct spot, you can use this ismember(final_code_guess...

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MATLAB determine if matrices are invertible or not
You can use rank( ) for this: https://www.mathworks.com/help/matlab/ref/rank.html?searchHighlight=rank&s_tid=srchtitle_rank_1 ...

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Using Trapezodial rule Matlab
The trapezoid rule is for situations where you know the function values in advance, but you don't have this situation. I.e., if ...

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fortran subroutine includes several other subroutines
Note that the timestwo.F example that comes with MATLAB is a bad example of Fortran code. It has several bugs in it that could l...

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Call C/C++ Code from MATLAB Code
If your code includes a file called MyStruct.h, then yes you should have such a file. I would expect it to be something like th...

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Matlab tries to use mex files not on search path
You should use debugging to find out why this is happening. Type the following at the command line: dbstop if error then run y...

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MATLAB: failed creating a diagonal matrix
You probably have inadvertently created a variable named 'diag' in your workspace, and hence diag(x) is simply indexing into thi...

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For-loops are now faster than some of the simplest vectorized statements. Why do we still need so much deep copying?
I have read rumors in the past that TMW was tinkering with the idea of sub-array references, or some type of limited pointer cap...

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what correction is required in the code?
If the homework assignment specifies you must use a loop, then I don't think the intent was for you to wrap a simple i=1 range a...

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I am trying to solve 3rd order ode by RK45, but I did not get solution and plot, kindly fix my issues
The image appears to show seven equations (H1', H2', ..., H7') with boundary conditions at 0 and infinity. The RK45 scheme you ...

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If statement in loop with AND OR operands
The problem is that the comparison Outcome{j} == '11_right' is an array comparison, not a scalar comparison. I.e., the string i...

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How to create a equally distributed batting order for little league baseball team
Start with a simple pattern that works, and then randperm both the rows and columns. E.g., B = zeros(10); for k=1:10 % start w...

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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 1-by-2
Does this do what you want: Xindex(r, :) = [index rowidx]; You can get rid of c altogether since it isn't needed. And you nee...

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How do I store a string from a MATLAB structure into a C structure in a MEX file?
Please show us the definitions of the variables involved. How large is cstructu->Field1, cstructu->Field2, and cstructu->Field3?...

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How to calculate sum(A .* (B * C), 'all') [Ed. actually sum(A .* log(B * C), 'all')] efficiently when A is sparse and B*C is full and large?
Here is the straightforward mex code (i.e., no parallel sections) if you want to try it out. It computes the result directly in...

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what does the expression " if ( ) && ( ) " do
&& is the "logical and" operator. You can read about it here: https://www.mathworks.com/help/matlab/ref/logicaloperatorsshortc...

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How to calculate sum(A .* (B * C), 'all') [Ed. actually sum(A .* log(B * C), 'all')] efficiently when A is sparse and B*C is full and large?
You could use this loop to avoid the memory usage, but it will run slowly because of the data copying going on in the background...

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ODE system with 2 degrees of freedom
I only see two variables, 1 and 2, and each is part of a 2nd order equation. So that would mean a 2 x 2 = 4 element state vecto...

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Extracting the sub-matrix
You might benefit from going through the onramp tutorials found here: https://matlabacademy.mathworks.com/details/matlab-onramp...

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How can I solve these differential equations?
A general outline would be to create your derivative function as follows: function dy = myderivative(t,y,T,E) Fa = y(1); Fb =...

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Exponent mantissa form of real numbers
Without seeing the actual wording of the assignment, I would assume this simply means "floating point notation". E.g., 123.456...

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Matrix product using for/while loop
The inner most loop needs to iterate over the 2nd index of M1, not the first index. E.g., while (k<=size(M1,2)) %<-- 2nd inde...

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What does 'li' mean?
1i is used to ensure it isn't confused with a variable named i that you might have in the workspace. I.e., 1i is always sqrt(-1...

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I have matrix A and I need to find (e^(At)) where t is the sampling time. How to find that? Also what is the difference between exp(A) and expm(A)?
exp(A) just takes the exp( ) of the scalar elements individually. I.e., exp(A(1,1)), exp(A(1,2)), etc. expm(A) takes the matri...

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help with my 4th order runge kutta code
My guess without seeing the rest of your code is that phi is a column vector, so when you add phi*h to the row vector Y(i,:) it ...

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how to change from for loop to while loop
You never change i or Errors within the while loop, so how is the loop ever supposed to exit? Maybe you want to add this line: ...

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Is mxCopyPtrToInteger4() not compatible with Interleaved Complex API ?
See this post: https://www.mathworks.com/matlabcentral/answers/93860-why-does-the-fortran-mex-api-function-mxcopyptrtointeger4-...

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