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Xingwang Yong


Last seen: 3 days ago |  Active since 2019

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Question


Command window sometimes disappears after maximizing editor
I would double click the editor to maximize it to have more space for debugging. After that, I double click the editor again to ...

1 year ago | 0 answers | 1

0

answers

Answered
Calling the error function does not print the line number in r2022b
Yet another un-wanted feature. The bug report says it is fixed, but in R2023a it is still there.

1 year ago | 1

Answered
Annoying pop-ups in Linux workspaces
For figures, I dock them, so it would not pop-up at all. For other UIs, I don't see how to solve this. % you may want to put it...

1 year ago | 0

Answered
Section color no longer an option in 2021b?
Improved appearance? The default color scheme in R2022a is already a mess. Not to mention the missing section highlight, which c...

2 years ago | 3

Answered
close a message box thru coding
m = findall(0,'type','figure','tag','Msgbox_ '); delete(m);

2 years ago | 3

Question


Figure zoom-in by mouse scroll is disabled after ROI is drawn
figure;imshow(imread('pout.tif')); Normally, I can use mouse scroll to zoom-in and zoom-out. But, if I draw ROI, imrect(); Th...

2 years ago | 1 answer | 0

1

answer

Question


How to create ROI object handle?
h = figure; imshow(imread('pout.tif')); imrect(); hg = findobj(h,'Type','hggroup') % How can I "create" a ROI object so th...

2 years ago | 3 answers | 0

3

answers

Question


Codegen failed to infer output size of built-in function, ??? Dimension 1 is fixed on the left-hand side but varies on the right ([1 x :?] ~= [:? x :?])
I tried to codegen a large file containing downsample(), below is a simplified one. For some reason, I have to specify the outpu...

2 years ago | 1 answer | 0

1

answer

Answered
Skip commas inside brackets when the expression has operators
expr1 = '(?<=\([^)]*),(?=.*\))'; % comma inside parenthesis, like '(..., ...)' index_comma_in_paren = regexp(line, expr1); On...

2 years ago | 0

Question


Numerical precision when using colon operator
I am doing simulation, which basically is iteration over time. Given the delta time dt and total time inter_pulse_space*num_puls...

2 years ago | 1 answer | 0

1

answer

Question


Zoom in using mouse scroll during uiwait sometimes fails
I want to zoom in a figure (with mouse scroll) during uiwait, however this did not always work. If you directly run main.m, y...

3 years ago | 1 answer | 0

1

answer

Question


When drawpolygon(), how to programtically delete a series of vertices?
I want to refine the automatically generated mask (denoted as init_mask below). I set corresponding points in drawpolygon(). ...

3 years ago | 1 answer | 0

1

answer

Question


Why would command syntax split string when using double quotes?
disp 'str ing' % good disp "str ing" % error, Too many input arguments I am on R2020a. It seems that the latter is equivalent ...

3 years ago | 1 answer | 0

1

answer

Answered
How do I write a loop in MATLAB that continues until the user presses any key?
A version uses nested function instead of global variable function myLoopingFcn2() KEY_IS_PRESSED = 0; gcf set(gcf, 'Ke...

3 years ago | 0

Question


Overlay image, code as function and code as script give differnt results
I want to overlay a colored image onto a gray image, and I found a solution here. If I run it as a script, it works perfectly. H...

3 years ago | 2 answers | 0

2

answers

Question


Colormap Editor, a "fixed" bug leads to other bugs?
In R2020a on windows 10, if you adjusted the system scaling factor, e.g. to 125%, then every time you open Colormap Editor, it w...

3 years ago | 0 answers | 1

0

answers

Question


Under what circumstance, mex-version of lsqcurvefit run slower than m-code of lsqcurvefit？
I converted a function to mex using Coder, which contains lsqcurvefit() to get some speedup. But this mex-version is slower than...

3 years ago | 0 answers | 0

0

answers

Question


Use coder to convert parfor-loop to mex, but mex version is much slower
I convert a function containing a parfor-loop into a mex file to get some speed up. But the mex version of this function is 5x t...

3 years ago | 0 answers | 0

0

answers

Question


Will codegen accelerate sub-functions?
I have functions look like % main.m function main() for i fun1(); end % fun1.m function fun1() for j fun2() ...

3 years ago | 1 answer | 0

1

answer

Answered
Handling bound constraints by the Levenberg-Marquardt algorithm
In matlab2020b, the doc of lsqcurvefit() has removed "The Levenberg-Marquardt algorithm does not handle bound constraints". So ...

3 years ago | 1

Answered
What is the alternate to eval function in a forloop?
Using cell array should help for i for j for k I{i,j,k}=getsiganl(filename1); II{i,j,...

3 years ago | 0

Answered
How to get Data type of workspace loaded variables and how add that datatypes using script?
s=whos; numBytes = sum([s.bytes]);

3 years ago | 1

Answered
Save and load variables of different samples
You could try cell(). You do not have to save the variable names. c = cell(1,1); % each col contains variables of a sample, eac...

3 years ago | 0

Question


codegen can't build the simplest demo
I am using codegen to build the 1st example in its doc, i.e. mcadd.m, it did not work. I am running Maltab2020a on CentOs 8.3. ...

3 years ago | 1 answer | 0

1

answer

Question


Call mex function using system()?
I downloaded a toolbox, which contains a pre-compiled mex file, foo.mexa64. The calling syntax is a little bit confusing, but ...

3 years ago | 1 answer | 0

1

answer

Question


How to customize callback after drag and drop a folder into command window?
For files, it is easy to customize a callback after drag and drop file into command window, as shown here. However, for folders...

4 years ago | 0 answers | 0

0

answers

Question


Using Matlab coder with lsqcurvefit(), can not pass optimoptions as an argument to the target function
I want to convert my function to mex using matlab coder. The function fits data to an exponential model. function ab_fitted = m...

4 years ago | 1 answer | 0

1

answer

Question


How does vectorized lsqcurvefit() calculate sum-of-square, row-wise or column-wise?
I have a 1001 measuments, in each measurement, there is a curve y = a*exp(-b*x) where x and y are vectors containing 8 element...

4 years ago | 1 answer | 0

1

answer

Question


In parfor-loop, can I call a multi-threaded mex and get some speed-up?
I learned the concept of multi-threaded mex from undocumentedmatlab. (It seems this website is unaccessible now ...) I am wonde...

4 years ago | 1 answer | 0

1

answer

Question


Mex, how to copy an array to output
In my mex function my_expm.c, I calculated matrix expoential for the input matrix, void mexFunction(int nlhs,mxArray *plhs[], i...

4 years ago | 1 answer | 0

1

answer

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