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# Alec Jacobson

### University of Toronto

Last seen: 4 dagar ago Active since 2016

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Question

Why does abs cause bad matlabfunction evaluation?
If I run x = sym('x','real'); y = sym('y','real'); f = abs(((x - 1)^2 + y^2)^(1/2) - 1)^2 + ((x^2 + y^2)^(1/2) - 1)^2; d2fdx...

### 3

Weird behavior regarding pi in symbolic expressions
@Walter Roberson's syms pi Pi = sym('pi'); answers aren't 100% satisfying because they are not really associating that variab...

Question

Why does converting in and out of LongBits introduce error?
In Java, double value = 0.007168281523489443; double res = java.lang.Double.longBitsToDouble(java.lang.Double.doubleToLongBi...

ungefär ett år ago | 1 answer | 0

### 1

Question

How to imshow to display colors consistently with other mac apps?
This appears to be a long standing issue but the question from 2015 didn't make much progress or reproduce easily. Here's what I...

mer än ett år ago | 0 answers | 0

### 0

Question

Matlab equivalent of Maple's remove_RootOf
I have a symbolic expression of the form root(…). I'd to recover the operand as a symbolic expression itself. I believe this wou...

mer än ett år ago | 1 answer | 0

### 1

Discrete Laplacian on a triangle mesh
L discretizes the integrated discrete Laplacian in the sense that: x' * L * x discretizes Dirichlet energy: ∫ ‖∇x‖² dx. Via Gre...

mer än 2 år ago | 0

| accepted

Submitted

gptoolbox
Useful functions for geometry processing, constrainted optimization and image processing.

Using print to export matlab figures to pdf: How to KEEP borders (and not crop them)
This question has been asked many times with zero answers that I could find. Here's a hacky partial work around for 2D plots whe...

mer än 3 år ago | 0

Question

MATLAB 2020b does not reload .m file edited outside of matlab until after running
I typically edit .m files outside of the matlab ide (using vim). Up until 2020b this was never an issue. In 2020b, if I make a c...

mer än 3 år ago | 1 answer | 0

### 1

Question

Is it possible to recover *the* decomposition that's ultimately employed by mldivide (backslash)?
If I issue: spparms('spumoni',1); A\b; Then I can see the decision made by mldivide on how to solve against A. In my case it ...

mer än 3 år ago | 1 answer | 3

### 1

I ran into this issue copy-pasting data in excel into a new sheet and saving as .csv. Seems on mac, this maneuver triggers Exce...

nästan 4 år ago | 0

Wait a boolean variable becomes false
The accepted answer will cause your CPU to spin (wasting precious power and computational resources). Instead, I found a "hack"...

nästan 5 år ago | 0

Can imread input animated gifs written using imwrite?
It seems like this is broken ... on purpose. In /Applications/MATLAB_R2017a.app/toolbox/matlab/imagesci/private/readgif.m...

mer än 6 år ago | 1

Question

Can imread input animated gifs written using imwrite?
I've written an animated gif test.gif using imwrite: sphere frame = getframe(gcf); [SIf,cm] = rgb2ind(frame.cdata,256...

mer än 6 år ago | 1 answer | 0