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James Tursa


Last seen: 1 day ago
3,748 total contributions since 2007

Interested in external applications, mex & engine applications with Fortran, C, C++, etc, particularly in the areas of speed improvement and memory management efficiencies.

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Answered
How do I make an if statement based on whether an index is part of a vector of numbers?
You can use the ismember( ) function for this. E.g., if ~ismember(currentcycle,abnormal_attractors) previous_expmean_v = c...

21 hours ago | 0

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Answered
multiply matrices with different dimensions with loop
Is this what you want? C = A .* B.';

1 day ago | 2

Answered
Madgwick filter - Quaternion Multiplication
I guess you could generate the following three expressions symbolically: original original + 1 - () original + () - 1 and th...

2 days ago | 1

Answered
How to I turn a fprintf column of values into a matrix
You can save all the values for plotting. E.g., xp = x0; yp = y; fp = f(x0); k = 1; for x = x0 : h : xn-h y = y + dy(x,y...

2 days ago | 0

Answered
Trying to go from Euler to Heun's Method
No, but you are close. You basically need to use the average of y' at the current state with y' at the Euler estimated next ste...

2 days ago | 0

Answered
Double sum - vector (matrix) solution
result = sum(C(:).*F(:)); or for later versions of MATLAB result = sum(C.*F,'all'); This all assumes that the actual indexing...

3 days ago | 1

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Answered
Generate list of 2 digit combinations without repetition
Can't you just use the nchoosek(0:9,2) result and add in the known double results 00, 11, etc.?

3 days ago | 0

Answered
Program to convert decimal to binary and vice versa
See https://www.mathworks.com/help/matlab/ref/dec2bin.html and https://www.mathworks.com/help/matlab/ref/bin2dec.html

3 days ago | 0

Answered
plotting complex exponential function
E.g., maybe this is what you need y = 1*exp( -i20 *pi * t ) + 4*exp( i20 * pi * t ); plot(t,y); Although it is not clear what...

4 days ago | 0

Answered
Coding Crowell's Method for Orbiting Bodies
I don't have the patience to go through all of your dim and dimc logic. It would seem to be much easier to code and debug if yo...

4 days ago | 0

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Answered
Plot the acceleration with ODE45
You find acceleration by taking the x solution from ode45( ) and feeding that back into your derivative function vdp1( ). Since...

4 days ago | 0

Answered
Multiplying by inverse of a matrix
You are essentially "dividing" by the X'*X quantity, so that is what needs to appear on the "bottom" of the slash. E.g., >> alp...

6 days ago | 1

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Answered
"Matrix Dimensions must agree"
t is used to build r, but it is not the same length as phi.

8 days ago | 1

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Answered
How to create a periodic function?
Not sure what you mean by "repeated at [2,10]". Maybe this: y = mod(x,2); ix = y > 1; y(ix) = 2 - y(ix);

9 days ago | 0

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Answered
How do i use output of one function as input to the other ?
You can do this at the point where you are calling the function neg. E.g., z = neg(pos(x,y),q);

9 days ago | 0

Answered
Index in position 1 is invalid. Array indices must be positive integers or logical values.
When i=m in your loop you try to access kernel(m-m,n-j) which is kernel(0,m-j), and 0 is an invalid index. Similar problems wit...

9 days ago | 0

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Answered
Solve a differential equation system with 4th order Runge-Kutta method with three equations
Not sure if you actually use t in your derivative functions, but you are missing that input from your j1, k1, and l1 code: ...

9 days ago | 0

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Answered
sum of cubes question
This homework question is poorly written: It seems like the intent of the n is to use it as the upper limit of the for-loop, bu...

9 days ago | 1

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Answered
Calling a function from another function
my_first_function1( ) doesn't return any value to the caller. To return a value you use this syntax: function absx = my_first_...

9 days ago | 1

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Answered
Numerical integration of the differential equation of motion of the two body problem
Your biggest problem is that you don't carry enough states in your derivative function. Your ODE is a 3D 2nd order equation, so...

10 days ago | 0

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Answered
How to swap multiple rows of a matrix at a time
A = your matrix A([1:63,142:202],:) = A([142:202,1:63],:);

11 days ago | 0

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Answered
Probability of binary sequence with Monte Carlo
First point is that probability of stopping at n=3 is not 2/6, it is (3/4)*(2/6) because you have to include the probablility th...

13 days ago | 1

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Answered
Problem at +/- 180 degrees in orientation estimation from IMU data
You can try the unwrap( ) function: https://www.mathworks.com/help/matlab/ref/unwrap.html

13 days ago | 0

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Answered
Help with secant method
You might look here which even includes example code: https://en.wikipedia.org/wiki/Secant_method

14 days ago | 0

Answered
How do I add an integer to every or any nth row
A(k,:) is the k'th row of A A(:,k) is the k'th column of A A([k m p],:) is the sub-matrix formed from the k'th, m'th, and p'th...

14 days ago | 1

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Answered
First and last occurrence of an element in an array
So the description of the problem doesn't say anything about consecutive values, so the code you have for that should be elimina...

14 days ago | 0

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Answered
Parse error at ']'
Looks like you just need commas instead of periods. E.g., [r,i,v,dr,di,dv]

15 days ago | 0

Answered
Simple Blackjack Simulation in MATLAB
A few things ... Seems like you should have this: deck = repmat([1,2,3,4,5,6,7,8,9,10,10,10,10],1,8); % two decks worth of car...

15 days ago | 0

Answered
Can not convert USHORT MAX to ufix16_Sp01
If you have a slope scaling of 0.01 and a bias of 0, doesn't that mean the max value is 65535*0.01 = 655.35?

15 days ago | 0

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Answered
Using ODE45 for coupled equations
General procedure: Define a variable, let's call it y to match the doc, that will be your state vector. Each element of y corr...

15 days ago | 0

| accepted

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