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James Tursa


3,063 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
Separate out every fourth element of a Vector
V = your vector result = V; result(4:4:end) = []; % remove every 4th element The above syntax with [] on the rhs is special ...

4 days ago | 0

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Answered
How to extract the value of dydt from ode45 function
Why can't you just call your odefcn( ) function with your solution t and xSol vector elements as inputs (e.g., in a loop)? Does...

4 days ago | 1

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Answered
How to make an assignment for my for loop?
This syntax with the curly braces next to SBOS means it is a cell array: SBOB{ whatever } But this syntax with the dot notatio...

4 days ago | 1

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Answered
Write binary file in Matlab
Can you read and write as “STREAM” in your FORTRAN compiler? No header stuff to worry about.

5 days ago | 0

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how binary floating point to real decimal number representation ?
You can't use dec2bin( ) reliably for this conversion in all versions of MATLAB because it is limited by flintmax (see note at b...

5 days ago | 0

Answered
Binary floating point Representation in Matlab
Did you try it? >> A=[ 0.1900 -0.0300 -0.1300 0 0.1500 -0.0700 0.0500 0.1600 -0.2500 -0.1900]; >> dec2bin(typecast(A,'uint...

5 days ago | 0

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Answered
Find sum of elements in a cell along the columns
Is this what you are trying to do? (using the curly braces) y = sum([A{2,:,1}])

8 days ago | 0

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Answered
Can somebody explain me this answer?
You are using linear indexing into "a". This matrix: >> 3*ones(2) ans = 3 3 3 3 When used as indexing, i...

8 days ago | 1

Answered
Using 3D array to subtract row Q from row P
It is unclear what you really want. If you want the Euclidean distance squared between rows, e.g., rows 1 and 3, then just d =...

10 days ago | 0

Answered
How to change radians into degrees?
Why are you using sym to find the angle? Just use atand( ) directly with the appropriate input. That seems to be the intent of...

12 days ago | 0

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I assign A = B; but I could not use A and B interchangeably
You are changing I_fted inside the loop. If you subsequently use it in another calculation within the loop, it would not be surp...

12 days ago | 1

Answered
matrix dimension reshape error
To solve your sizing issues, type the following into MATLAB: dbstop if error Then run your code. When the error occurs, your c...

12 days ago | 0

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Is it possible to 'clear all' variables except one?
Another method is the FEX keep utility: https://www.mathworks.com/matlabcentral/fileexchange/181-keep

12 days ago | 0

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MKL 2018 supposedly supports integer matrix multiplication. Can this feature be added to Matlab?
The main problem with matrix multiplication on integer types (int32, etc.) in MATLAB is that the operation result is ambiguous i...

14 days ago | 0

Answered
Convert 0×1 empty double column vector to zero
Is this construct all you need? if( isempty(x) ) x = 0; end

18 days ago | 0

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Answered
How to use randperm with minimum spacing between random numbers
Maybe something like this will suffice for your needs? p = b * randperm(floor(n/b),k) If n/b isn't an integer value, then ther...

18 days ago | 0

Answered
How do you append to a matrix within a for loop when the matrices are unequal in size?
Maybe you could use a cell array. E.g., : D1 = cell(1,N); for a=1:N : D1{a} = C; end Then the first matrix...

19 days ago | 1

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Answered
What is the best way to save to .csv without losing precision and with column headers?
Why are you using fprintf in a loop? Can't you do it all in one call? E.g., this for i = 1:length(x) fprintf(fid,'%f , %...

20 days ago | 0

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Answered
Error: Too many output arguments.
Your function isn't coded to return anything. Try this: function timber_length = GET_NEAREST_LENGTH(length) Btw, "length" is t...

21 days ago | 0

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Answered
write a function to translate a 3d object
You didn't write your function to return an output. Try this: function S = shift(S,dist,axis)

21 days ago | 1

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Answered
dlmread adds low precision digits
Any function (dlmread, fscanf, etc) in any language (MATLAB, C, etc.) reading text numbers into floating point will have this is...

21 days ago | 1

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Answered
function f(x)=xe^x
Take a look at this loop from your code: for j=1:length(x) y = (1/N)*(a+((j-1)*h)); % <-- This replaces y at each step ... it ...

21 days ago | 1

Answered
Extending an order in a vector
One way: >> result = cell2mat(arrayfun(@(y)x*y-x+1:x*y,y,'uni',false)) result = 1 2 3 7 8 9 13 ...

22 days ago | 1

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Answered
How to Run filename.mexw64 in command prompt
Assuming you are on a WIN64 system, call it just like any other function. E.g., my_result = filename(my_arguments); The filena...

22 days ago | 0

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Pass pointer to scalar variable in mex function
"... The only way I've gotten around this before is by making the scalar variable into a vector and just using the first element...

25 days ago | 0

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2D summation loop
Take the denominator for instance. Literally written out, this would be denominator = 0; for k=1:K denominator = denomin...

26 days ago | 0

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Answered
Get a matrix by interaction
Maybe use cell arrays. E.g., BCG{gen} = horzcat (dx1, dy1, dx2, dy2, dx3, dy3, SLL); Then everywhere downstream in your code, ...

27 days ago | 0

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Answered
Implicit expansion with empty arrays
In the 1st case, you are expanding a dimension of 1 (the 3rd dimension of the first operand) to 0, so it is scalar expansion. I...

27 days ago | 0

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Answered
how to add all 2d matrices in a 4D matrix???
sum(sum(your_matrix,4),3) or sum(reshape(your_matrix,10,50,[]),3)

27 days ago | 0

Answered
Save values in each iteration
The loops aren't needed. E.g., Ccl = 21; % Number of column elements gene = 5; % Number of times the column is generated min...

28 days ago | 0

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