Matlab

about scalar and Sparse Matrix multiplication
I met a strange problem about the scalar and Sparse Matrix Multiplication. The following expression: v=0.25*M*w is equivalent to v=M*w; v=0.25*v; where M is a sparse matrix However, the latter is much faster way than the former way (about ten time). Why? Thanks ... 19 Jan 2010 03:34

finding the four corners pixel location values of a small reectangular image in a large image
hi , can anybody help me in finding the edges(4 corners) of a small rectangular image in a large image. i have to find the both the index value of the four corners and their corresponding x and y pixel location. the small imagew is look like arectangle but it is not an exact rectangle. please help me to find the co... 18 Jan 2010 23:14

State Space Model Parameter Estimation
I have a state space model of a thermal system for which I am trying to design a temperature estimator. There are a few parameters within my state matrix that are difficult to calculate offline very percisely, and for which I currently have estimated values as place holders. I also have test data with which to cor... 5 Feb 2010 17:18

how to do a running max efficiently in Matlab?
Here is an simple implementation. But I need to run this as an inner loop millions of times... How to make it more efficient? Hopefully without the for loop? Thanks! nMax=data(1); for i=2: length(data) nMax=max(data(i), nMax); end; ... 20 Jan 2010 17:25

Shape recognition
How to determine the specific shape with more object in the background.For example, There have 6 different object,how to recognize only one object via their shape? Thanks ... 23 Jan 2010 08:43

Position of xtick marks
I would like to move the xtick marks so that they do no appear at the center of a data point but on the boundary between points. That is, if I create a plot using a = [1,2,3,4,5,6,7,8,9,10] a = repmat(a,5,1) imagen(a) I will get a plot of 10 evenly spaced vertical color bars. The default behavior of Matlab is ... 18 Jan 2010 22:08

Position of xtick marks
I would like to move the xtick marks so that they do no appear at the center of a data point but on the boundary between points. That is, if I create a plot using a = [1,2,3,4,5,6,7,8,9,10] a = repmat(a,5,1) imagen(a) I will get a plot of 10 evenly spaced vertical color bars. The default behavior of Matlab is ... 18 Jan 2010 22:08

code for reverse arrangements test
Does anyone have the code for this test? If yes, please share it with me. ... 23 Jan 2010 01:13

changing files using a for loop
All, Its probably a very simple answer, but its eluded me for hours. I have multiple large files that cannot all be open in the workspace due to memory requirements. I have the user input which file to load from the current directory. As each file is loaded I then attempt to us operate on the variables just loaded... 19 Jan 2010 05:44

Matlab crashes on image/surf
Hi. Whenever I try to do image or surf, there is about a 1 in 10 chance that matlab will simply close with the standard windows "this program has encountered an error" dialog. I suspect opengl problems based on google results, but no suggested fixes work for me. I am running matlab 2009a and 2009b on a Windows 2... 8 Feb 2010 00:11