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# David Doria

326 total contributions since 2007

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Responded

Re: Changing the font size changes the axes limits?
The placement of 'hold' doesn't seem to change anything. This does work as I'd expect, thanks. I agree, the default should b...

3 years ago | 4380 views

Responded

Re: Changing the font size changes the axes limits?
Steve, I tried: t=0.1:.1:1.1; data=exp(-1*t) ; line(t, data); hold on; set(gca,'YTickMode','manual') set(gca,'YLimMode','manua...

3 years ago | 4380 views

Posted

Changing the font size changes the axes limits?
Consider the simple plot: t=0.1:.1:1.1; data=exp(-1*t) ; line(t, data); At this point, the y axis is from .3 to 1, and the x ax...

3 years ago | 4380 views

Question

How to synchronize multiple timeseries
The synchronize() function only takes 2 timeseries arguments. What is the standard procedure if you need to sync more than 2 tim...

3 years ago | 1 Answers | 1

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Posted

roifill equation
Usually the documentation is very specific about the underlying mathematics, but this function: http://www.mathworks.com/help/to...

4 years ago | 1378 views

Question

second color of bar() always black?
I am trying to plot two bar plots on the same graph. When I do: bar(aout1, a1, 'r'); hold on; I see the red bars, as ex...

4 years ago | 2 Answers | 0

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Question

mex -setup doesn't seem to find my compilers?
I am trying to set mex to use gcc4.4 (my system default is 4.6, but I also have installed the 4.4 package). I read that 'mex -se...

5 years ago | 1 Answers | 0

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Posted

Height and shape of FFT peaks
I made this very simple program to convince myself of a few things: % Create a summed wave, with a sampling rate of 1e-4 second...

5 years ago | 2978 views

Posted

Finding the normal to a binary contour image
Consider a binary image of the outline of a circle (black background, black interior, white boundary). If you use a standard gra...

6 years ago | 2416 views

Posted

normxcorr2 documentation
http://www.mathworks.com/help/toolbox/images/ref/normxcorr2.html#bqkhmom-1 In the second term in the denominator of the only eq...

6 years ago | 1813 views

Posted

Call for volunteers: GlobalText Image Processing Book
Hi Matlab users, I have offered to head up a book called "A Practical Introduction to Image Processing" for the GlobalText proj...

6 years ago | 2143 views

Responded

I see. I was looking through the derivest_demo.m and saw this example: % Compute the numerical gradient vector of a 2-d function...

7 years ago | 5193 views

Responded

Actually I have one comment/suggestion. Is there a way to wrap this in a function? If you have a 10-D function, this would be a ...

7 years ago | 5193 views

Responded

Exactly what I was looking for - thanks and good work John! Dave

7 years ago | 5193 views

Posted

All the examples in the gradient() documentation seem to be interested in computing the gradient over a grid. Is there a way to ...

7 years ago | 5193 views

Responded

Re: blank ezplot?
Any thoughts? Dave

7 years ago | 3323 views

Posted

blank ezplot?
If I have this function: function PlotPolynomialClassifier(W) syms x; syms y; f = W(1) + W(2) * x + W(3) * y + W(4) * x^2 + W(5)...

7 years ago | 3323 views

Responded

Re: Ezplot constants?
Great - thanks all!

7 years ago | 3496 views

Responded

Re: Array of class objects?
Yep, that's the one - thanks!

7 years ago | 3291 views

Posted

Ezplot constants?
I want to plot some quadratic functions with varying coefficients, for example: syms x syms y ezplot('2*x^2 + 3*y^2 = 1') but ...

7 years ago | 3496 views

Posted

Array of class objects?
If I have a class: classdef DataPoint end And I want a bunch of DataPoint's in an array, I thought I would make a cell array ...

7 years ago | 3291 views

Posted

missing 1/NM in corr2 documentation?
Should there be a 1/NM term inside the square root in the corr2 documentation? r = corr(A,B)/(std(A) std(B)), so each double su...

7 years ago | 1985 views

Responded

Re: Problem with fit
The toolbox is capable of finding exp(bx) for b positive or negative without specifying a starting point. It was the same model ...

7 years ago | 2799 views

Responded

Re: Problem with fit
John, I see what you mean with rand(), but I was just trying to make it so that the model was not a perfect fit. A "lack of fit...

7 years ago | 2799 views

Posted

Problem with fit
If I generate some data, add some noise, and then fit it to the same model it was generated from, it works properly. %generate ...

7 years ago | 2799 views

Responded

Re: Color a list of points with a list of colors
Bruno, I was trying to avoid the loop because if you have a large number of points the GUI slows to a crawl unless all the point...

7 years ago | 1906 views

Posted

Color a list of points with a list of colors
I want to do something like this: plot([0 1],[0 2],'color',[.5 .3 .4; .1, .1, .2], 'marker', 'o') Is it possible? Thanks, Dave...

7 years ago | 1906 views

Responded

Re: Building a 3D surface by giving coordinates (in a struct)
X,Y] = meshgrid(x,y); Z = griddata(x,y,z, X, Y); figure; surf(X,Y,Z); Who knows why they don't provide a function to do this......

8 years ago | 21226 views

Responded

Re: plot data in multi dimensional space
To expand... PCA is principal component analysis. The idea is that you can see which dimensions out of those 30 are "most impo...

8 years ago | 5377 views

Responded

Re: need help with Error message
use the "step over" function of the debugger to figure out which line the problem occurs on and then use the size() function to ...

8 years ago | 858 views