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# Michael

Con actividad desde 2012

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"text" handle, how do I grab all text and rotate it in a figure?
Hi, I've created a figure and annotated it using "text(x,y,'sample)" code, and I've got about 8 instances of it on my figure....

más de 9 años hace | 1 respuesta | 3

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Fastest way to compute spectral norm of a matrix?
Hello I can't find any mention of the spectral norm in the documentation. I want to calculate max(|Ax|)/x for any vector x...

más de 9 años hace | 1 respuesta | 0

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colorbar scientific notation exponent won't go away
Hi I've got a square matrix and I'm using imshow and colorbar to plot it. The values are small, so colorbar naturally uses x1...

más de 9 años hace | 0 respuestas | 1

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i've an gray scale image I to be decomposed...i want to extract the low frequency and high frequency component out of it...can anybody help me?
I don't know what LL1 or HH1 are but the 2D discrete Fourier transform should find you the frequency components of the image, in...

casi 10 años hace | 0

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How to plot 3D contours of temperature, on the 3D surface of the body !?
My own suggestion might be to generate the 3D surface using g = surf(x), remove the edges using set(g,'EdgeColor','none'), and t...

casi 10 años hace | 1

Pregunta

MATLAB automatically chose colours for my plot, how do I get them?
ydata is 70x5 xdata is 70x1 plot(xdata, ydata) generates five lines with different colours how do I find what these colou...

casi 10 años hace | 1 respuesta | 0

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best way to plot error bars for multiple data?
Hi I have five pairs of curves to plot on a 2d graph. This, I can just about manage- I use five colours and then distinguish ...

casi 10 años hace | 0 respuestas | 0

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how to assign a variable using a string
I have a set of variables called "error1", "error2", etc. Each is a 4D matrix and I want to extract certain parts of them for...

casi 10 años hace | 2 respuestas | 0

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use of cell arrays to store matrices... but parfor gives an error
Hi, I've got a loop which creates three matrices, and I want to store these for each iteration. Previously I've been saving t...

casi 10 años hace | 1 respuesta | 2

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Pregunta

what is the mathematical notation equivalent to abs(A) for matrix A?
I'm trying to write notes for my code and I want to know if there's a common notation which means what abs(A) does, ie. multiply...

casi 10 años hace | 2 respuestas | 0

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preallocating sparse 4d matrix
Hi I've got some code that preallocates some matrix L = zeros(50,50,50,50); and then iterates along the first two dimensions ...

casi 10 años hace | 2 respuestas | 0

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why does parfor execute loops in a random order?
I can't see any reason why, and if my PC crashes during a 20,000 loop iteration, it's a pain to figure out which iterations are ...

casi 10 años hace | 1 respuesta | 0

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"print" saves image with tiny title/xlabel
Hi I'm trying to save a figure using 'print' but this process doesn't preserve the image/text proportions that are on my scre...

casi 10 años hace | 2 respuestas | 0

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imresize is blurring my image!
Hello I have a 128x128 matrix and I want to scale it down to 32x32. MATLAB's algorithm "imresize" seems to involve a smoothin...

casi 10 años hace | 1 respuesta | 0

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setting processor affinity for individual parallel toolbox workers
Hi Just wondering does anyone know if there are any general rules for improving speed by setting processor affinity using the...

casi 10 años hace | 0 respuestas | 0

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Matlab loop (with load/save) is getting slower and slower
Hi I'm running a large code that is basically: for i = 1:50 load(i.mat, input); output = myfun(input); ...

alrededor de 10 años hace | 3 respuestas | 0

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Want to change the range of a single axis of a plotyy figure
Hi I want my x-axis to be tight to the data on a plotyy graph. I can't seem to do it without messing up the axes. My data ...

alrededor de 10 años hace | 2 respuestas | 0

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Does logical indexing have a direct inverse?
Say I have some region-of-interest filter X, and I use B = A(X~=0) to only extract the values of A where X~=0, is it then possib...

alrededor de 10 años hace | 4 respuestas | 1

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How to stop recurring error message if Ctrl+C doesn't work!? (help!!!)
Hi I tried to surf plot a discrete Laplacian matrix operator and it has broken MATLAB... I managed to close the figure, but t...

alrededor de 10 años hace | 2 respuestas | 0

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Pregunta

Stopping fmincon based on timer
Hi, I asked this before and accepted an answer before having some trouble implementing the code, so I think I need to ask again....

alrededor de 10 años hace | 3 respuestas | 1

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Can I impose a time limit on fmincon without editing the m-file?
I'm trying to compare different algorithms by imposing a time limit, however one of my algorithms calls fmincon and it seems imp...

alrededor de 10 años hace | 1 respuesta | 0

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fmincon displays huge unwanted output text
Hi. Does anyone know why fmincon would ignore a 'Display','off' setting in the options? Here is my code: opt = optimset('Ma...

alrededor de 10 años hace | 1 respuesta | 0

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Non linear curve fitting by changing parameters
What is the blue curve? Usually a curve fitter algorithm requires a model (your h function) with specified parameter space (your...

alrededor de 10 años hace | 0

Pregunta

How to reshape a 16x16x16x16 matrix to 256x256 whilst maintaining consistency
Hi I have a pixel grid (16,16) and I've generated a matrix A whose (i,j,k,l)th element specifies a property of the pairing of...

alrededor de 10 años hace | 1 respuesta | 0

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How to quantify the spread/separation of points on a circle
Hi, this may be a little vague I have a set of points in the unit circle and I want to quantify their separation, for example...

alrededor de 10 años hace | 1 respuesta | 0

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lsqcurvefit.m ... how to find intermediate steps?
Hi I'm fitting using lsqcurvefit and the OUTPUT structure tells me there are 4 steps with 20 function evaluations before the ...

alrededor de 10 años hace | 2 respuestas | 0

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Radon Transform
If the ellipse has a uniform value the integral becomes the product between that value and the length of each beam through the e...

más de 10 años hace | 1

Pregunta

apply filter to a *circular* image
hello I'm trying to filter a circular image, the circle fits inside a square matrix, so for a 100x100 matrix the radius is 50...

más de 10 años hace | 1 respuesta | 0

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Multiplying certain dimensions of two 3D matrices
Hi I've got two matrices, one 30x30x50 and one 30x30x80 I would like to multiply them in such a way that the result is a 5...

más de 10 años hace | 3 respuestas | 0

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merging column vectors from the loop in to a single matrix
Try something like: matrix = zeros(rows, columns); % preallocate your matrix for i = 1:columns column = [your code he...

alrededor de 11 años hace | 1