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daviddoria (340) 158 Articles, 182 Replies, 340 Points

Since 5/20/2012 12:59:05 AM, daviddoria has written 158 articles and participated in 182 conversations.
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daviddoria

daviddoria's articles:
 Items(158) /16 Next >> Last >| Changing the font size changes the axes limits? 7 50 (8/9/2013 1:18:07 PM) comp.soft-sys.matlabConsider 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 axis is from .1 to 1.1. The function is displayed from one edge of the white pa...David roifill equation 0 70 (7/7/2012 2:00:07 PM) comp.soft-sys.matlabUsually the documentation is very specific about the underlying mathematics, but this function: http://www.mathworks.com/help/toolbox/images/ref/roifill.html just says "by solving Laplace's equation". Does ...David Height and shape of FFT peaks 2 72 (7/25/2011 4:43:09 PM) comp.soft-sys.matlabI made this very simple program to convince myself of a few things: % Create a summed wave, with a sampling rate of 1e-4 seconds (sampling frequency 1/1e-4=1e4=10kHz). Fs = 1e4; t=0:1/Fs:.1; % create .1 secon...David Call for volunteers: GlobalText Image Processing Book 1 43 (6/28/2010 3:00:31 PM) comp.soft-sys.matlabHi Matlab users, I have offered to head up a book called "A Practical Introduction to Image Processing" for the GlobalText project http://globaltext.terry.uga.edu/ . Their mission is to have people write "open...David Numerical gradient 5 48 (11/23/2009 2:26:19 PM) comp.soft-sys.matlabAll the examples in the gradient() documentation seem to be interested in computing the gradient over a grid. Is there a way to find the gradient at a single point? I.e. Rather than this: v = -2:0.2:2; [x,y] =...David blank ezplot? 2 44 (10/30/2009 4:10:19 PM) comp.soft-sys.matlabIf 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) * y^2; %doesn't work %f = W(1) + W(2) * x + W(3) * y + W(4) * x^2; %works ezplot(...David Ezplot constants? 3 78 (10/17/2009 3:47:03 PM) comp.soft-sys.matlabI want to plot some quadratic functions with varying coefficients, for example: syms x syms y ezplot('2*x^2 + 3*y^2 = 1') but I want to iterate/vary the '2' and '3' in that expression, something like a = 2 b ...David Array of class objects? 3 36 (10/13/2009 6:50:18 PM) comp.soft-sys.matlabIf I have a class: classdef DataPoint properties Point ClassId end methods function DP = DataPoint(Point, ClassId) DP.Point = Point; DP.Cla...David missing 1/NM in corr2 documentation? 1 39 (5/8/2009 8:54:01 PM) comp.soft-sys.matlabShould 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 sum in the denominator is supposed to be a variance, so they should be divided by NM...David Problem with fit 4 34 (4/26/2009 5:25:03 PM) comp.soft-sys.matlabIf I generate some data, add some noise, and then fit it to the same model it was generated from, it works properly. %generate a set of points from an exponential function x = 0:.1:3; x=x'; y = 2* exp(-3*x)'; ...David

daviddoria's replies:
 Items(118) /12 Next >> Last >| Changing the font size changes the axes limits? 7 50 (8/9/2013 1:18:07 PM) comp.soft-sys.matlabConsider 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 axis is from .1 to 1.1. The function is displayed from one edge of the white pa...daviddoria (340) Numerical gradient 5 48 (11/23/2009 2:26:19 PM) comp.soft-sys.matlabAll the examples in the gradient() documentation seem to be interested in computing the gradient over a grid. Is there a way to find the gradient at a single point? I.e. Rather than this: v = -2:0.2:2; [x,y] =...daviddoria (340) blank ezplot? 2 44 (10/30/2009 4:10:19 PM) comp.soft-sys.matlabIf 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) * y^2; %doesn't work %f = W(1) + W(2) * x + W(3) * y + W(4) * x^2; %works ezplot(...daviddoria (340) Ezplot constants? 3 78 (10/17/2009 3:47:03 PM) comp.soft-sys.matlabI want to plot some quadratic functions with varying coefficients, for example: syms x syms y ezplot('2*x^2 + 3*y^2 = 1') but I want to iterate/vary the '2' and '3' in that expression, something like a = 2 b ...daviddoria (340) Array of class objects? 3 36 (10/13/2009 6:50:18 PM) comp.soft-sys.matlabIf I have a class: classdef DataPoint properties Point ClassId end methods function DP = DataPoint(Point, ClassId) DP.Point = Point; DP.Cla...daviddoria (340) Problem with fit 4 34 (4/26/2009 5:25:03 PM) comp.soft-sys.matlabIf I generate some data, add some noise, and then fit it to the same model it was generated from, it works properly. %generate a set of points from an exponential function x = 0:.1:3; x=x'; y = 2* exp(-3*x)'; ...daviddoria (340) Color a list of points with a list of colors 4 48 (3/22/2009 4:04:01 PM) comp.soft-sys.matlabI 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 ...daviddoria (340) Building a 3D surface by giving coordinates (in a struct) 5 37 (1/23/2009 6:55:04 AM) comp.soft-sys.matlabHey there!! I'm trying to build a 3D surface. I used a struct to build my data-base witch includes 3 fields "x", "y", "z". Now, after my bata base is built and ready and have all the coordinates I collected, I...dandul_d (4) need help with Error message 3 49 (12/17/2008 12:23:03 AM) comp.soft-sys.matlabDear all: I was trying to run the script, but keep getting the same error message. It happened everytime I run the "for" loop. Can anyone give any suggests what would be the problem? The script as follows: ---...yangzhuo_wu (7) plot data in multi dimensional space 5 51 (12/16/2008 9:42:02 AM) comp.soft-sys.matlabHi, In my project, I am trying to diagnose a disease from a set of symptoms. For diagnosing D1 disease I have a 25~30 input parameters (it differs for one according to the age, sex, race etc (nxm matrix, n sym...boomas (4)