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Jacobian of scalar matrix
gradient() computes partial derivatives approximately, using finite differences. It can't compute the exact partial derivatives ...

10 years 前 | 0

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Possible to apply filter2 to only values above a limit?
Compute the filtered version for all pixels, and simply replace the pixels above a certain value with their filtered value: ...

10 years 前 | 0

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Can classes be made unsaveable
No. When a class object is saved, the saveobj method for that class gets called, if it exists. If this method throws an error, i...

11 years 前 | 0

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提问

Can classes be made unsaveable
Is there a way to define a class such that the MATLAB save() function throws an error when it tries to save an instance of that ...

11 years 前 | 1 个回答 | 1

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Optimization problem - reducing the time needed to solve
ConstLM.m looks very inefficient to me. I think those loops can be vectorized. Profile your code, and learn about vectorization....

11 years 前 | 0

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Interpolation between matrices (image attached)
Your query location, (0,10), is in the center of your grid, so if you want a linear interpolation between the input matrices you...

11 years 前 | 0

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difference between imadd and imfuse
Yes.

11 years 前 | 0

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Saving axes to file - trouble with copyobj and export_fig
Regarding the error using export_fig, it seems you didn't install the package correctly.

11 years 前 | 0

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export_fig can't do Monospace?
Export_fig supports Courier, and that is monospaced. For hints on why the other fonts you mentioned might not be working, see...

11 years 前 | 0

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Is there a way to make device memory persist between CUDA MEX calls
Yes, you can reinterpret_cast the pointer to an integer of a sufficient bit length, e.g. uint64, and return this to MATLAB. Then...

11 years 前 | 2

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Indexing multiple values over large array?
histc outputs the bin index of each input value in the second output argument. So you can do: [~, ind] = histc(vals); va...

11 years 前 | 0

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Gray Image to Color Indexed Image
Use the <http://www.mathworks.co.uk/matlabcentral/fileexchange/16233 sc()> package. A = sc(image, [0.4 1], 'hsv');

11 years 前 | 0

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PNG image created in Matlab shows up as all black in imshow
If you read the imshow help text, you'll see that the range only applies to grayscale images. Try: imshow(double(A)/4095);...

11 years 前 | 0

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How to optimise/vectorize loop containing the function "imrotate", using multiple images and angles as input
Assuming your 900 input images are all the same size, you could: # For each rotation angle, compute the location of each rota...

11 years 前 | 0

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bitget for array (count no. of bits)
I assume from your question that you actually want to do a vectorized bitcount, rather than a vectorized bitget. If that is corr...

11 years 前 | 0

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Which MATLAB operations/functions need speeding up?
Linear 2D interpolation for multi-channel images A common computation in computer vision, and many other fields, is sampling ...

11 years 前 | 0

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What functions can benefit from simple patching?
I gave a patch for saveas <http://www.mathworks.co.uk/matlabcentral/answers/13085#answer_17979 here>.

11 years 前 | 0

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Which MATLAB operations/functions need speeding up?
REPMAT Repmat is unnecessarily slow. Internally it produces an index array, which it then uses to create the output array. Th...

11 years 前 | 0

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Which MATLAB operations/functions need speeding up?
BSXFUN with builtin functions Bsxfun is useful in that it allows us to vectorize elementwise operations between arrays of dif...

11 years 前 | 2

提问

Which MATLAB operations/functions need speeding up?
When using MATLAB, I sometimes come across a performance bottleneck caused by functionality that I believe could be much faster....

11 years 前 | 23 个回答 | 3

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How should I compute the eigenvectors of a sparse, real, symmetric matrix?
Just convert the matrix to a full one, and use eig. Unless less you want just a few eigenvectors, then the decomposition using t...

11 years 前 | 0

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提问

How should I compute the eigenvectors of a sparse, real, symmetric matrix?
I need to compute all the eigenvectors of a sparse, real, symmetric matrix, A. I've tried the following: >> [V, D] = eig...

11 years 前 | 3 个回答 | 0

3

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Requirements for using parfor across multiple desktop PCs
You need a licensed copy of MATLAB and the Parallel Computing Toolbox on the PC running the parfor loop, and you need a licensed...

11 years 前 | 0

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提问

Requirements for using parfor across multiple desktop PCs
I have several desktop PCs running Windows, connected over a network, all with access to a common file system. I would like to d...

11 years 前 | 1 个回答 | 0

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problem with errorbars and export_fig
Export_fig exports error bars just fine. Try: x=1:10; y=x.^2-2*rand(size(x)); err=abs(x.^2-y); errorbar(x,y,err,...

11 years 前 | 1

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Placing plots into multiple page pdf document
The <http://www.mathworks.co.uk/matlabcentral/fileexchange/31215-appendpdfs append_pdfs> function can concatenate separate pdf f...

12 years 前 | 1

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How to define paper orientation in export_fig for pdfs
The export_fig submission <http://www.mathworks.co.uk/matlabcentral/fileexchange/23629-exportfig description>, help text and the...

12 years 前 | 0

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Best way to share code within laboratory
We use a version controlled repository, stored on a central server.

12 years 前 | 0

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Mix raster / vector in ps / pdf plots
I believe <http://www.mathworks.com/matlabcentral/fileexchange/727 exportfig> (which is different from <http://www.mathworks.com...

12 years 前 | 0

提问

How do I change figure mode programmatically?
My figure has the rotate/zoom tool selected, and I wish to deselect it programmatically. How can I do this?

12 years 前 | 1 个回答 | 1

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