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In a sorted vector ,how do I compare first element to other elements and then find if there are any duplicates , if yes take their indexes and replace it with 0
For array with finite elements A.*[1,diff(A)~=0]

7年以上前 | 1

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extract field from a structure problem
depending on the content, if scalar tmp=[DP1.P] or if not tmp={DP1.P}

7年以上前 | 1

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How to solve this matrix?
>> P=[0.2 0.4 0.4; 1 0 0; 0.5 0.25 0.25] P = 0.2000 0.4000 0.4000 1.0000 0 0 0.5000 ...

7年以上前 | 0

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Intersection of three and more arrays
My FEX returns the index of the arrays

7年以上前 | 0

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How to randomly choose 3 values from the first column.
A(randperm(size(A,1),3),1)

7年以上前 | 2

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How can I find a fit to my data points and using triangulation to approximate the planar area?
Quick and dirty fix, just discard outside delaunay triangles with long sides load('x-data.mat'); load('y-data.mat'); xy = [...

7年以上前 | 0

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Overcome for loops for fast processing
skin_rgb = 0; for i = [2000 : 2003,2008,2010:2011,2013:2015,2017:2018,2021,2024,2027:2041,2043,2045:2059,2061:2063] I = im...

7年以上前 | 1

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calculation of a mean
splitapply(@mean,data,ceil((1:size(data,1))'/10))

7年以上前 | 1

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Combinations of a vector with replacement
A = [2 3 4] [A1,A2] = ndgrid(A); arrayfun(@(k) polyval([A2(k),A1(k)],10), 1:numel(A1)) [A1,A2,A3] = ndgrid(A); arrayfun(...

8年弱前 | 1

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Rotate 3D axis camera perspective about arbitrary direction vector
Here is a demo to show using Camera parameters, I also put the rotation matrix R in comment. I find MATLAB parameters more intui...

8年弱前 | 0

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How to efficiently multiply each element of a matrix with every other element of two other matrices, i.e. in least time possible?
[m,n] = size(A); AA = reshape(A,1,1,m,1,1,n); BB = reshape(B,1,m,1,1,n,1); CC = reshape(C,m,1,1,n,1,1); V = AA.*BB.*CC; V =...

8年弱前 | 0

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Replace values in one column based on the content in several other columns.
A = [1 1 1 0; 1 2 1 1; 2 1 1 3; 1 1 1 3; 2 1 2 4] B = [1 1 1 1; 1 2 1 0] [b,loc] = ismember...

8年弱前 | 0

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CAN I FIND FLOPS FOR A CODE WHICH I HAVE WRITTEN
If you can find an old R6.0 of MATLAB, and your code is able to run with it there is a command floops(). Since MATLAB use LAPAC...

8年弱前 | 0

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Creating a vector which goes across all x y and z values
The dot product between [0 2 0] and [x,y,z] is 2*y So just do dotresult = 2*y

8年弱前 | 0

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Creating a georeferenced polygon
You can get a linear connected contour (polygon) by C = contourc(lat,lon,double(isfinite(dro_dom_fill)),0.5*[1 1]); C = C(:,...

8年弱前 | 0

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how to find the first element that satisfy a condition in a matrix?
Try this for j = 1:ny idx_start(:,j) = find(Dwf(:,j)> 0.01,1,'first') ; idx_end(:,j) = find (Dwf(:,j) < 0 & (1:nx)...

8年弱前 | 0

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Compiling with Matlab instead of interpreting
MATLAB calls FFTW library behind the scene, so if you are doing heavily FFT for convolution, there is not much speed penalty. I...

8年弱前 | 1

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Rotate 3D axis camera perspective about arbitrary direction vector
HGTRANSFORM ?

8年弱前 | 0

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How to order vertices of a flat convex polygon in 3d space along the edge?
<</matlabcentral/answers/uploaded_files/140726/PolySorted.png>> xyz =[... -2.6055 1.1850 0.0880; -2.6320 1.170...

8年弱前 | 3

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Overdetermined system of equations - 8 degree polynomial
If you rescale your data, making for example x coordinates between (-1,1) it might hep to get a better condition linear system. ...

8年弱前 | 1

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How to find the largest factor of a number using while loops?
largestfactor=floor(n/2); while largestfactor>0 if mod(n,largestfactor)==0 break end larges...

8年弱前 | 1

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If i have array defined as G=(83 27 125 99 0 25 255 ..... ) .Is there any command or code to find S as defined below ?
correct ranging if the minimum of G starts from 0: clear S S(G+1) = 1:numel(G)

8年弱前 | 0

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Quaternions, Transformation Matrix
Such thing is straight forward in MATLAB q1 = reshape(q1,1,1,[]); q2 = reshape(q2,1,1,[]); q3 = reshape(q3,1,1,[]); ...

8年弱前 | 0

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What is background technique of fsolve ?
The relevant information is in Algorithm part in the bottom of the <https://fr.mathworks.com/help/optim/ug/fsolve.html Doc>, jus...

8年弱前 | 0

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How can I plot 3D surface x^3 + y^3 + z^3 = 1, where x, y, z are in unit closed interval in MATLAB ?.
<</matlabcentral/answers/uploaded_files/140679/xyzcube.png>> <</matlabcentral/answers/uploaded_files/140680/xyzcube.png>> ...

8年弱前 | 1

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Combining K matrices in one matrix
X = reshape(cat(3,a,b,c),[],3)

8年弱前 | 1

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How to construct the n*n matrices, like below:
Such matrix is a FEM/discrete laplacian, and I strongly recommend using sparse matrix whene ever solving PDE. n = ... S ...

8年弱前 | 0

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How to solve 3 equations dependent each other?
_Actually i thought it is going to be easy but when i write the code for wx, i realized that wx is increasing with time but wz a...

8年弱前 | 0

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Index exceeds the number of array elements (1) error
%assign initial gues to unknowns th3(k)=x(1);th5=x(2); th6=x(3);to=x(4); I think it should be ...

8年弱前 | 0

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Interp1 returning NaN for ode45
V = interp1(V,t_interp,t,'pchip'); It looks arguments are swapped; I think it should be V = interp1(t_interp,V,t,'pchi...

8年弱前 | 1

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