Submitted

SAREK - Sparse Analyzer Real Et Komplex
The SAREK function analyzes a sparse matrix for integrity. Useful especially for checking sparse matrices built by 3rd party s/w...

6 maanden ago | 5 downloads |

Answered
Help with state representation of my 3-mass 2-spring system
The k terms in the equations above appear to be non-linear. Your A matrix doesn't account for the cubic parts.

6 maanden ago | 0

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Calculate angles correctly between two vectors using the dot product.
Also see this related link for a robust method using atan2 that can recover small angles: https://www.mathworks.com/matlabcentr...

7 maanden ago | 0

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How can I make memory persistent between calls to a MEX-file in MATLAB?
So, the accepted answer has bugs. Namely: They don't include the header for memcpy They don't check the input argument properl...

7 maanden ago | 0

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Index in position 1 exceeds array bounds (must not exceed 8).
Here is how to debug these types of errors: Type the following at the command prompt: dbstop if error Then run your code. Whe...

7 maanden ago | 0

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matlab mex in-place editing via "mxUnshareArray" or similar functionality
So, MATLAB has never officially supported modifying input variables in-place in a mex routine. There are potential side effects ...

7 maanden ago | 0

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Static methods are unnecessary, right?
I use Constant Properties and Static Methods all the time in classes I am creating. In particular, when I am developing a group...

8 maanden ago | 1

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Speed of the abs function
Although I applaud your thinking about this problem, this level of optimization is hard to achieve with a language such as MATLA...

8 maanden ago | 2

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How would I write these in MATLAB
Depends on what those subscripts mean. E.g., maybe this y41 = -(x41^1.5 * cos(x41)^3) + 40; y42 = x42 * sin(x42^2); or this ...

8 maanden ago | 0

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How to find roots of a quartic function with unknown constant coefficients?
You can look here: https://en.wikipedia.org/wiki/Quartic_function But the nature of the roots is going to depend on the value ...

8 maanden ago | 0

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What calendar system does MATLAB use?
I know this is an old post, but the accepted answer is a bit misleading. MATLAB certainly does use a specific calendar system. ...

8 maanden ago | 3

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Rungekuttan for a system of 2 DOE functions
It would be better to have a single state vector for your solution so that you can easily compare your results to MATLAB ode45( ...

8 maanden ago | 0

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How much data does an array take?
The data is held in contiguous memory, so yes for a full real double an NxN matrix would take 8*N^2 bytes for the data. Then the...

9 maanden ago | 0

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Multiply matrices in cell array by another matrix
You may be stuck with the loop. There are ways to rearrange and stack things so that you can do everything in a single matrix m...

9 maanden ago | 0

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Reading a large binary file
Try data = fread(fd, '*int16'); When you use 'int16' for the type to read, MATLAB reads as int16 and then converts to double (...

9 maanden ago | 1

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Incorrect Dimensions for matrix multiplication
Because you are using matrix operators instead of element-wise operators. Try this: Rtf=(cosh(m.*Lf)+(h./(m.*Kf)).*sinh(m.*Lf))...

9 maanden ago | 0

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Why is pow2() slow? Fastest way?
Another way is just to add d to the exponent bits. Probably fastest to do this in a mex routine where edge checking can easily b...

9 maanden ago | 0

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Values are getting converted to double automatically.
Here is what I get just displaying the character string. I inserted brackets [ ] for concatenation: ab=[0.5,0.75,1,1.25,1.5,2];...

10 maanden ago | 2

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help with parallelization of matrix operations
Both of these operations can be multi-threaded in the background, but this kind of timing test is not straightforward to do beca...

10 maanden ago | 0

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Field II kidney example does not work due to "Requested array exceeds the maximum possible variable size." error
At first glance this is the obvious problem in the original source code: The dimensions array needs to be the proper integer si...

10 maanden ago | 0

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Question

Is there a classdef startup/initializer method?
When a classdef is first loaded into memory (via object instance creation or static method call etc.), is there a way to get a s...

10 maanden ago | 1 answer | 1

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Question

How to update leap seconds
The current version of MATLAB has a function to give you the leap second information that it is using. E.g., [T,vers] = leapsec...

10 maanden ago | 2 answers | 0

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A MEX solution to split classdef-defined object arrays into cells
You need to use mxGetProperty( ) to get at the properties of a classdef object. And since this returns a deep copy, no need for ...

10 maanden ago | 1

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Why does accessing a multi-dimensional array with fewer indices than its total dimensions not result in an error in MATLAB R2022b?
The accepted answer is misleading. When you access a multi-dimensional array with fewer indexes than its total dimensions, MATLA...

11 maanden ago | 3

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Create Mex files for Matlab, from .FOR files of Fortran
So, I haven't had access to a Fortran compiler in over 10 years. And as a result I haven't been maintaining any of my Fortran F...

12 maanden ago | 0

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Unusal error "Current use of the variable is inconsistent with its previous use or definition".
See how the +b is purple? That means MATLAB thinks you are invoking a as a function with +b as a character string input. Hence ...

12 maanden ago | 1

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Question

Incorrect datetime UTCLeapSeconds conversion
I am working with leap second data, and as part of the calculations I did this for a particular leap second: dt1 = datetime(197...

12 maanden ago | 1 answer | 0

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How to add rows containing zeros to a matrix
E.g., one way using the end syntax: my_matrix = reshape(1:12,3,4) n = 4; % number of rows to append my_matrix(end+n,1) = 0 B...

12 maanden ago | 0

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error using tranpose (recieving permute error )
If you are trying to transpose the initial 2D pages of your variable, you can do this: pagetranspose(featvales) Or this: d = ...

12 maanden ago | 0

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Error L2 is not defined
You have a fundamental problem with your code. You have a 2nd order ODE, which means there will be two states you need to carry ...

12 maanden ago | 0