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# Yi-xiao Liu

Last seen: 3 months ago Active since 2020

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Question

MATLAB and Fortran gives different results (precision)
I have 2 small programs in MATLAB and Fortran, respectively, which should be identical MATLAB version f=zeros(size(r1,1),3); ...

5 months ago | 1 answer | 0

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Question

FFT spectral leak?
I find that in the power spectrum returned by fft the amplitude of peaks are much smaller than expected, even for artifical sign...

7 months ago | 1 answer | 0

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Efficient way to divide array into tiles
I use the following code to divide array into tiles n=2;nrow=3;ncol=3; A=reshape(1:36,6,6) A=mat2cell(A,zeros(nrow,1)+n,zer...

7 months ago | 1 answer | 0

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Intersect() with with repetition
Here is my current solution. A=[1,1;1,1;1,2]; B=[0,1;1,1;1,1]; [uA,~,iA]=unique(A,"rows","stable"); iA=sortrows([iA,(1:...

10 months ago | 0

Question

Intersect() with with repetition
The syntax [C,ia,ib] = intersect(A,B,'rows') returns elements without repetitions. However, I need every potential combination o...

10 months ago | 4 answers | 0

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Printing figure alters content details
I have brought this to MATLAB support, they concluded that this is an visual artifact produced by the renderer when the on-scree...

10 months ago | 0

Question

Printing figure alters content details
I am trying to print some figures generated by imagesc into png images for portability. However, I found the output to lose some...

11 months ago | 2 answers | 0

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Exporting large figure on headless servers
I am trying to export some large figures (~1e4 by 1e4 surf plots) into bitmap images directly on our HPC cluster. Here is some t...

11 months ago | 0 answers | 0

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Question

pre-allocating disk space for matfile objects containing cell arrays of large sparse matrices
I have a custom function that consumes O(n^2) RAM in intermediate steps and generates very sparse outputs. The current strategy ...

11 months ago | 0 answers | 0

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Equivalent of A&(~B) without using ~
Hat tip to @David Goodmanson and @Stephen23. I found 4 solutions: A=rand(5)<0.6;B=rand(5)>0.2; ref=A&(~B); Method1=A; Me...

12 months ago | 0

| accepted

Question

Equivalent of A&(~B) without using ~
I am looking for a way to generate the same output as A&(~B) w/o using the ~ operator. The problem is both A and B are very larg...

12 months ago | 1 answer | 0

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Question

Slicing matrices to fit in memory
I have a custom vectorized function whose space (and time) complexity is O(n^2). The problem is that n is very large, ~1e6, and ...

12 months ago | 0 answers | 0

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implicit expansion for arrayfun
Apparently arrayfun is a build-in function and I cannot access its source code. Here is what I come up with. [a,b,c,d]=Implicit...

1 year ago | 0

Question

implicit expansion for arrayfun
I want to do something similar to bsxfun, but for more than 2 arrays. For example arrayfun(@f, A,B,C,D) where A is a m-by-...

1 year ago | 2 answers | 0

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Question

Find the index range of ones/trues?
For example, given a logical vector: [0,0,1,0,0,1,1,0,1,1,1,0,0...] I need a two-column matrix: [3,3; 6,7; 9,11;...] tha...

2 years ago | 2 answers | 0

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I want to construct a vector xq (the query vector) from xs (sample point vector) for use in interp1. Ideally, xq would: contain...

2 years ago | 1 answer | 0

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Why does this vectorized version does return the same as a for loop?
I am trying to sum the inter-electrostatic forces of n points at r=[rx,ry,rz] However, the vectorized version does not return...

2 years ago | 0 answers | 0

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Question

Does event location terminate ODE solver at tspan?
I just wonder what's the behavior of this edge case: a event location is setup to terminate the intergration, however the event ...

2 years ago | 0 answers | 0

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Warning: Matrix is singular, close to singular or badly scaled. Results may be inaccurate. RCOND = NaN. when switching to stiff solvers
OK, I am going to answer my own question here. After providing Jpattern, the ode15s works normally, but does not display any ...

2 years ago | 0

| accepted

Question

Warning: Matrix is singular, close to singular or badly scaled. Results may be inaccurate. RCOND = NaN. when switching to stiff solvers
I am solving a system of ODE to model electrospinning, which could be described as n Viscoelastically connected point charge ...

2 years ago | 1 answer | 0

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Question

Solving vectorized ODE (Solving same ODE with many initial conditions at once).
I am tring to apply 2nd newton law to many points, where m,r,v,f is a n-by-1, n-by-3, n-by-3, n-by-3, n-by-3, matrixes for mass,...

2 years ago | 2 answers | 0

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Question

Logical indexing 3D array to get a 2D slice
I have a piece of code that calculates potential for 3D space. Now I want to extract the potential at the YOZ plane: [X,Y,Z]=me...

2 years ago | 1 answer | 0

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I am tring to reconstruct a surface in cylinderical coordinate space from set of points. theta,R,z represents azimuthal, radial,...

2 years ago | 0 answers | 0

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I have been using scaled MAD in isoutlier and it has done a wonderful job. However, I wonder what's the mathematical basis of th...

2 years ago | 1 answer | 0

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Question

Compare 2 regression models
I wonder if there is any tool to compare 2 regression models on the same sample pool. In general more terms you put into the mod...

2 years ago | 1 answer | 0

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Question

Finding the ranges where scatteredInterpolant is above threshold
I have been using scatteredInterpolant to reconstruct surfaces from actual measured data points. To address the slight misplacem...

2 years ago | 1 answer | 0

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Question

Assign different marker to different errorbar lines
h=errorbar(cell2mat(X2D),cell2mat(Y2D),cell2mat(E2D)); legend(Grouplabel); mkrs=['o';'d';'s';'^';'+';'x']; I use the above co...

2 years ago | 0 answers | 0

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Question

How do I add labels next to the 3 180 xticks? Like sampleA for the first one, sampleB for the second, etc. Thanks! >> xt = xt...

2 years ago | 1 answer | 0

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Question

Function to output multiple figures
I am trying to write a function that could output multiple figures function [fig1,fig2] = FunctionName(Input1,Input2,Input3) ...

3 years ago | 0 answers | 0