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James Tursa


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3.223 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
Create an .m file
To create an .m file for a function named randint, you can do this at the command line as long as the default directory is your ...

ongeveer 9 uur ago | 0

Answered
How to read a binary file with below description?
E.g., fname = the name of your binary file fp = fopen(fname,'rb'); k = fread(fp,6,'int16'); y_start = k(1); y_end = k(2);...

ongeveer 11 uur ago | 0

| accepted

Answered
Output argument is not assigned on some execution paths.
What happens if you change this elseif imbalance <= 0 to this else

ongeveer 12 uur ago | 0

Answered
Does this character vector match any of the following character vectors?
You could use cell arrays. E.g., use ismember(currentMonth,{'June','July','August'}) instead of strcmp(currentMonth,'June'||...

ongeveer 12 uur ago | 0

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Answered
I am getting wrong answer for factorial(22)
R2016a PCWIN64: >> a1 = factorial(22) a1 = 1.124000727777608e+21 >> b = (sqrt(2*pi*22))*(22^22/exp(22)) b = 1.11...

3 dagen ago | 1

Answered
generating random values with condition
You could use this FEX submission by Roger Stafford for each 4 number block: https://www.mathworks.com/matlabcentral/fileexchan...

3 dagen ago | 0

Answered
How to Convert a function return is a Handle (C++ mex)
DEVICE_HANDLE is a pointer, so if you are running 64-bit MATLAB then DEVICE_HANDLE will be be 64-bits and will not fit in a 32-b...

8 dagen ago | 0

Answered
Runge kutta 4 with two ODE's - function inside a function
Since W is a function of time, it needs to match the time that you are using in each particular line of code. E.g., take this l...

10 dagen ago | 1

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Answered
Converting output from 'find' into a logical
E.g., x = the result of the find y = false(22879,1); y(x) = true; But it may be better to create y with a direct logical exp...

10 dagen ago | 0

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Answered
Remove all infinite values from ydata and then remove those same indices from the xdata so the vectors remain the same length
x = isinf(ydata); ydata(x) = []; xdata(x) = []; Or, if you need to extract the values into new variables, x = ~isinf(ydata);...

11 dagen ago | 0

Answered
Different results by changing the order of operations
You haven't broken up the calculations properly. I.e., you are comparing different calculations. Your code is essentially: ...

12 dagen ago | 1

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Answered
Grabbing sections of a matrix by using two doubles as the index
E.g., result = arrayfun(@(x1,x2)data(x1:x2),find(indStart),find(indEnd),'uni',false); This assumes of course that the indStart...

25 dagen ago | 1

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Answered
1-2-1 or X-Y-X rotation matrix not supported
According to the doc here: https://www.mathworks.com/help/aerotbx/ug/angle2quat.html?s_tid=doc_ta The angle2quat supports the ...

29 dagen ago | 1

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Answered
Plotting a System of Two Second-Order Differential Equations
You've got a 4th order system, so your initial state must contain four elements including the x1' and x2', not two. E.g., [t, ...

30 dagen ago | 0

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Answered
hex2num can't recover value from the hex by num2hex
Try typecast(uint32(hex2dec('be361af6')),'single')

ongeveer een maand ago | 1

Answered
Rotation order of quatrotate
I suppose this drawn out explanation is long overdue in this forum, so forgive me for being verbose, but a lot of posters have h...

ongeveer een maand ago | 0

Answered
Comparing any of the matrix input
Hints: What does this result give you: classes == x Then look at this: doc any

ongeveer een maand ago | 0

Answered
()-indexing must appear last in an index expression.
You've got closing and opening parentheses next to each other: ...)(... MATLAB thinks you are trying to use the second part as...

ongeveer een maand ago | 0

Answered
Single precision matrix multiplication
To illustrate what Matt is saying, a simple timing test: >> format longg >> S = round(10000*single(rand(5000)+rand(5000)*1i));...

ongeveer een maand ago | 2

Answered
Using MEX file with the main program of Fortran code
You would need to turn the PROGRAM line into a MEXFUNCTION line and add some code for getting the MATLAB variable data to/from t...

ongeveer een maand ago | 0

Answered
An explicit Runge Kutta of Fourteen Order code
4th Order RK is here: https://en.wikipedia.org/wiki/Runge%E2%80%93Kutta_methods

ongeveer een maand ago | 0

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Answered
Why does mxSetDoubles crash this MEX file?
This line is crashing your code: mxSetDoubles(plhs[0],a); You can't re-use data pointers this way. You have essentially share...

ongeveer een maand ago | 0

Answered
Highest power of 2 that divides n.
In addition to David's comments, you need to do all of the calculations symbolically, so all of these should be sym: 2, i, r.

ongeveer een maand ago | 0

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Answered
Can someone help me convert C++ to Matlab
The += and *= operators behave as follows: total_salary += daily_salary; becomes total_salary = total_salary + daily_salary; ...

ongeveer 2 maanden ago | 0

Answered
Operands to the || and && operators must be convertible to logical scalar values
Did you mean this for u = 1:height<=u for v = 1:width<=v to be this for u = 1:height for v = 1:width

ongeveer 2 maanden ago | 0

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Answered
find max of vector
Two things. FIrst, you need to initialize pos = 1 before the loop starts. And second, you need to modify your if-test to do tw...

ongeveer 2 maanden ago | 0

Answered
How to define an axis based on multiple quaternions?
Assume you have the following: q1 = quaternion from ECI to BODY at time1 (i.e., BODY1 frame) q2 = quaternion from ECI to BODY ...

ongeveer 2 maanden ago | 0

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Answered
Repeat elements of a vector as matrixes in a multidimensional array.
Another way: m = size of 1st dimension n = size of 2nd dimension v = your row vector result = reshape(repmat(v,m*n,1),m,n,[]...

ongeveer 2 maanden ago | 1

Answered
Sorting numbers in an array without sort function
Simply set your "finished" flag depending on whether a swap was done or not. E.g., while true finished = 1; for i=1:s...

ongeveer 2 maanden ago | 0

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Answered
Need help finding intercept in a polynomial function
Why can't you just find the real roots of f(x)-600? What am I missing here?

ongeveer 2 maanden ago | 0

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