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Matt J


6,112 2009 이후 총 참여 횟수

Professional Interests: medical image processing, optimization algorithms

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Nested For Loop for 2D Matrix
So then you want to extract random 51x51 submatrices? If so, then, I=sort(randperm(600,51)); J=sort(randperm(1000,51)); sub...

약 1시간 전 | 0

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The result of rotation matrix rotx(angle) with a coordinate does not give the desired result
Here's what my AxelRot utility gives https://www.mathworks.com/matlabcentral/fileexchange/30864-3d-rotation-about-shifted-axis?...

약 3시간 전 | 0

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how can I find the coordinates of the central axis of a river in an image (binary)?
load River C=watershed(bwdist(A))==0; [icoords,jcoords]=find(C); %coordinates of center line imshow(A+C)

약 3시간 전 | 2

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Count the number of intersections between any two curves
The only general way (i.e., for arbitrary curves) is using the Symbolic Math Toolbox, solve(curve1==curve2)

약 5시간 전 | 1

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How to match a number between two characters?
>> str=extractBetween("[180] Windabweichung","[","]") str = "180"

약 8시간 전 | 0

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How to match a number between two characters?
>> T=regexp('[180] Windabweichung','\[(\d+)\]','tokens'); T{:} ans = 1×1 cell array {'180'}

약 8시간 전 | 0

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Images as the Options in a Drop Down Menu
See here, https://undocumentedmatlab.com/blog/icon-images-in-matlab-uicontrols

1일 전 | 1

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License Manager error -96 (of matlab 2018b)
This may help https://www.mathworks.com/matlabcentral/answers/95122-why-do-i-receive-license-manager-error-96?s_tid=answers_rc1...

3일 전 | 0

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how can i find the stationary points of this equation and find its nature in the region x>0.
You can use diff to get numerical approximations of the derivatives and apply stationary point criteria based on those. If need...

3일 전 | 0

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The best way to write a large number of constraints for an optimization problem
If they are linear constraints, they will be expressed using matrix-vector multiplication A*x<=b Aeq*x<=beq so any vectorized...

5일 전 | 0

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How do I remove NaN values from a cell array?
The presence of NaNs isn't the problem. The problem is that the cell contents are character vectors of different lengths. You ca...

5일 전 | 0

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Fmincon linear contraint doens't work in my case
You should check the EXITFLAG output to see if fmincon believes it converged. If it did converge, the ranges should be satisfied...

6일 전 | 0

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How can i create a convolution using toeplitz matrix?
Consider >> x=1:5, y=rand(1,5), x = 1 2 3 4 5 y = 0.2899 0.4714 0.8782 0.6555 ...

6일 전 | 0

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답변 있음
fminunc: get Hessian approximation after each iteration
You could try running fminunc 1 iteration at a time in a for-loop and saving the 6th output arguments, options.MaxIter=1; ...

6일 전 | 0

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답변 있음
Using FFT in for-loop is extremely slow - how to accelerate?
To conserve memory, I only store the results for x,y,z inside the mask. It would be straightforward to re-embed them in 4D array...

6일 전 | 0

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Can someone propose some code that will "connect the dots" to produce the correct geometric shapes (i.e., hexagons, pentagons, rectangles) from these points?
Here is a refinement of my earlier answer which I think performs better. It uses the attached classdef file to create objects re...

7일 전 | 1

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Create matrix (30 x 12) with numbers from 1 to 12 without repetition without any repetitions of following numbers for each row
Note that there are only >> nchoosek(12,2)*2 ans = 132 distinct subsequences of length 2 that can be drawn from the numbe...

7일 전 | 0

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Can someone propose some code that will "connect the dots" to produce the correct geometric shapes (i.e., hexagons, pentagons, rectangles) from these points?
This seems to do it. For the display part, it uses plotpts2d, which you've seen before. maxDistLine=10; %User tolerance s...

10일 전 | 0

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Data: Interp1 spline and cubic method
how would you approximate this data using the Interp1 function and spline method For example, year=[1;2;3;4;5;6;7;8;9;10]; po...

10일 전 | 1

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Can I set restrictions on the output matrix from "linprog" before solving?
If X is constrained to be binary (using intlinprog rather than linprog), then this condition is equivalent to the linear inequal...

11일 전 | 0

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Derivative constraint in curve fitting
You can do spline fits with those kinds of constraints using this, https://www.mathworks.com/matlabcentral/fileexchange/24443-s...

11일 전 | 1

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Why parfor could read the deleted script?
Remember that in a parfor loop, you are responsible for ensuring that no operations in the loop that depend on the order of exec...

12일 전 | 0

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Converting 3D matrix to a bigger 2D matrix efficiently
[ma,na,~]=size(A); B=permute(reshape(A,ma,na,2,2), [4,1,3,2]); B=reshape(B,2*ma,2*na)

12일 전 | 1

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답변 있음
Converting 3D matrix to a bigger 2D matrix efficiently
Is there an efficient way to create the B matrix without using loops? There is nothing inefficient about using loops in this ca...

12일 전 | 2

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How to check the internal solution results of Fsolve to know where the matrix dimension assignment has problem?
Yes, if you re-run your code after executing >> dbstop if caught error at the command line, the code will pause execution at t...

12일 전 | 1

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Unable to perform assignment because brace indexing is not supported for variables of this type.
grade = cell(1,length(fish)); price = cell(1,length(fish)); use = cell(1,length(fish)); % preallocate cell array. Also, these...

13일 전 | 0

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matrix multiplication without declaring the destination matrix first
You can loop backwards. Then the pre-allocation will be done silently. clear C2 for i = N:-1:1 for j = N:-1:1 fo...

13일 전 | 0

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lsqcurvefit add a constraint
No, you cannot supply any constraints except simple bounds with lsqcurvefit. You do need to use fmincon. Write an objective func...

13일 전 | 0

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Take average of the nearest n pixels
If you have the Statistics Toolbox, you could use knnsearch, https://www.mathworks.com/help/stats/knnsearch.html

14일 전 | 0

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Parameter estimation - estimate integers only
If your objective and constraints are linear, you can use intlinprog. Otherwise, if you have the Global Optimization Toolbox, an...

14일 전 | 0

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