David Epstein

Last seen: mer än ett år ago | Active since 2012

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Professional Interests: mathematics, scientific research

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Question

Display figure on screen
After I run my program, I have to click on the Window menu at the top of my screen, and select Figure 1. Figure 1 then displays...

mer än 5 år ago | 0 answers | 1

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answers

Question

Don't want my points on the boundary
This code puts my points on the boundary of the plot , which I don't want. Have tried setting xlim large, and various other ap...

mer än 5 år ago | 2 answers | 0

2

answers

Answered
Which files are read before startup.m?
The answer to my question is given at https://uk.mathworks.com/help/matlab/matlab_env/when-path-not-successfully-set-at-startup...

nästan 6 år ago | 1

| accepted

Question

Which files are read before startup.m?
Whenever I start Matlab, I get two lines of error message in red. I would like to find out what is causing them and how to get r...

nästan 6 år ago | 1 answer | 1

1

answer

Question

How to vectorise the code below
I have asked about fsurf two or three times on this platform, and received two replies, neither of which extracted me from my di...

nästan 6 år ago | 1 answer | 0

1

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Question

fsurf and function handles.
I rewrite my question in the hope of making it clearer. Let be a vertical half-plane in bounded by the vertical axis . In , w...

nästan 6 år ago | 0 answers | 0

0

answers

Answered
Create image matrix by choosing pixels interactively.
I solved this using a Matlab plot with ginput in a loop collecting one click each time it went through the loop. This built up t...

ungefär 6 år ago | 0

| accepted

Question

Create image matrix by choosing pixels interactively.
Given a positive integer n (say n=50), I want to make an n x n white box with black boundary, and black grid lines, dividing it ...

ungefär 6 år ago | 1 answer | 0

1

answer

Question

window for several figures.
MATLAB Version: 9.4.0.813654 (R2018a), running under MacOS 10.13.6. I run a script that computes 3 figures. This produces 3 thu...

mer än 6 år ago | 1 answer | 0

1

answer

Question

"Linear" algorithm for griddedInterpolant
Try this M=rand(2,3); disp(M); F=griddedInterpolant(M); disp([F(1,1),F(1.5,2.5),F(2,3),F(50,19),F(-50,19)]); Wh...

mer än 6 år ago | 1 answer | 0

1

answer

Question

What is M(I) where M is a real matrix and I is a matrix of indices.
M is a 67x67 matrix of doubles. I is a 441x2 matrix, with I = [xc,yc]. Each row is a pair i,j of indices of M. I want to apply...

mer än 6 år ago | 1 answer | 0

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Question

getting an image matrix when I have the image.
My code to produce a white F on a black background: f_shape = [0,0;1,0;1,2;2,2;2,3;1,3;1,5;3,5;3,6;0,6;0,0]*[1,0;0,...

mer än 6 år ago | 1 answer | 0

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Question

is it possible to vectorise the following. I want to construct all pairs of integers (I,j) with i^2 + j^2 <= r^2, This includes negative i and j. Ideally I want a 2 by k matrix listing my pairs in lexicographic order. At the moment I use for loops.
Given r, I want to construct all pairs of integers (i,j) with i^2 + j^2 <= r^2, This includes negative i and j. Ideally I want ...

mer än 6 år ago | 1 answer | 0

1

answer

Question

cross-correlation one large image and many small images
I have one large NxN image (grey scale), and many small nxn images (n always the same). Both N and n are powers of two. Padding ...

nästan 8 år ago | 0 answers | 0

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answers

Question

MSER conventions for the direction of increase of the y-variable
I have found what I think is a clash of conventions in Matlab's treatment of MSERs. When using pixel coordinates, it is conventi...

mer än 8 år ago | 0 answers | 0

0

answers

Question

Argument to dynamic structure reference must evaluate to a valid field name
Here is a code snippet that results in the error message recorded in my question. The program passes the if clause that starts ...

mer än 8 år ago | 1 answer | 0

1

answer

Question

error detection when reading in text
I have a long file of which this is a typical sample 11-Aug-2015 102.3 12-Aug-2015 103.4 14-Aug-2015 101.7 15-Aug-...

ungefär 9 år ago | 1 answer | 1

1

answer

Solved

Make the vector [1 2 3 4 5 6 7 8 9 10]
In MATLAB, you create a vector by enclosing the elements in square brackets like so: x = [1 2 3 4] Commas are optional, s...

mer än 12 år ago

Solved

Column Removal
Remove the nth column from input matrix A and return the resulting matrix in output B. So if A = [1 2 3; 4 5 6]; and ...

mer än 12 år ago

Solved

Determine if input is odd
Given the input n, return true if n is odd or false if n is even.

mer än 12 år ago

Solved

Times 2 - START HERE
Try out this test problem first. Given the variable x as your input, multiply it by two and put the result in y. Examples:...

mer än 12 år ago