matlab

ploting 3d graph in matlab?

Hello, I am currently a begineer, and i am using matlab to do a data analysis. I have a a text file with data at the first row is formatted as follow: time;wave height 1;wave height 2;....... I have column until wave height 19 and rows total 4000 rows. Data in the first column is time in second. From 2nd column onwards, it is wave heig...

MATLAB command for exporting geometry from pdetool

I'm writing a MATLAB script which solves for the eigenmodes of a defined polygon. MATLAB's PDE toolbox lets me define the geometry using the command pdepoly() but I need to export the geometry description matrix manually to the workspace through the GUI before I can decompose, mesh, and solve the pde. Does anyone know either a command to...

Octave / Matlab: How to plot the roots of a polynomial

Hi everyone, Im trying to plot the roots of a polynomial, and i just cant get it. First i create my polynomial p5 = [1 0 0 0 0 -1] %x^5 - 1 r5 = roots(p5) stem (p5) Im using the stem function, but I would like to remove the stems, and just get the circle around the roots. Is this possible, is stem the right command? Thanks in adva...

Uniform distribution of binary values in Matlab

I have a requirement for the generation of a given number N of vectors of given size each consistent of a uniform distribution of 0s and 1s. This is what I am doing at the moment, but I noticed that the distribution is strongly peaked at half 1s and half 0s, which is no good for what I am doing: a = randint(1, sizeOfVector, [0 1]); ...

Finding whether a value is equal to the value of any array element in MATLAB

Can anyone tell me if there is a way (in MATLAB) to check whether a certain value is equal to any of the values stored within another array? The way I intend to use it is to check whether an element index in one matrix is equal to the values stored in another array (where the stored values are the indices of the elements which meet a ce...

Interpolating 1D Gaussian into 2D Gaussian

Let's say I have a 1D Gaussian function. Its length is 600 for that matter. I want to Interpolate it into 2D Gaussian of the size 600 X 600. This is the code I wrote (OTFx is the Gaussian Function, OTF - 2d Interpolated Function): [x, y] = meshgrid([-300:299], [-300:299]); r = sqrt((x .^ 2) + (y .^ 2)); OTF = interp1([-300:299], OTFx...

MATLAB arbitrary code execution

I am writing an automatic grader program under linux. There are several graders written in MATLAB, so I want to tie them all together and let students run a program to do an assignment, and have them choose the assignment. I am using a C++ main program, which then has mcc-compiled MATLAB libraries linked to it. Specifically, my progra...

Plotting multi-colored line in Matlab

I would like to plot a vertical line (I'd prefer any orientation, but I'd be happy with just vertical right now) with two-color dashes, say red-blue-red-blue-... I know I could do it like this: plot([1,1],[0,1],'r'), hold on, plot([1,1],[0,1],'--b') However, since I need to be able to move the line, among others, it should only have ...

matlab plot and line

What's the difference between function plot and line in matlab? Are they doing the same thing? Thanks! ...

Problem with averaging corrupted images to eliminate the noise in MATLAB

I want to average some .jpg images which are corrupted by zero-mean Gaussian additive noise. After searching around, I figured out to add the image matrices and divide the sum by the number of matrices. However, the resultant image is totally black. Normally when the number of image increases then the resultant image gets better. But whe...

Matlab and MrVista

I'm new to MATLAB and mrVista. I'm running Matlab Version 7.8.0.347 (R2009a) 32-bit(win32) from February 12, 2009 OS is Windows 7 Professional I downloaded the most recent MrVista_hourly.zip and extracted it into my C:\Program_Files_(x86)\MATLAB directory. I think I need to run mrvInstall, but when I do, I get the following: EDU>> ...

Calculating the maximum distance between elements of vector in MATLAB

Let's assume that we have a vector like x = -1:0.05:1; ids = randperm(length(x)); x = x(ids(1:20)); I would like to calculate the maximum distance between the elements of x in some idiomatic way. It would be easy to just iterate over all possible combinations of x's elements but I feel like there could be a way to do it with MATLAB's ...

In MATLAB can I convert a java boolean to a MATLAB logical?

In MATLAB I'm using a couple of java routines I've written to interface with a MyQSL database. One routine returns a boolean value result <1x1 java.lang.Boolean> >> result result = true When I then use it in a conditional statement I get an error message. >> if result, disp('result is true') end ??? Conversion to logical from java....

Tidying up a list

I'm fairly sure there should be an elegant solution to this (in MATLAB), but I just can't think of it right now. I have a list with [classIndex, start, end], and I want to collapse consecutive class indices into one group like so: This 1 1 40 2 46 53 2 55 55 2 57 64 2 67 67 3 68 91 1 94 ...

Changing scaling of MATLAB Figure

I have a figure that displays 20,000 points on the x-axis. So it labels the x-axis from 0 ... 20,000. However, now I would like to scale it from 0 to 50. But when I try to do this in the plot window it just shows me the first 50 points, instead of changing the scale. Is there any straightforward way to do that in MATLAB? ...

How to parse the file name and rename in Matlab

I am reading a .xls file and then procesing it inside and rewriting it in the end of my program. I was wondering if someone can help me to parse the dates as my input file name is like file_1_2010_03_03.csv and i want my outputfile to be newfile_2010_03_03.xls is there a way to incorporate in matlab program so i do not have to m...

How can I get a list of all the defined variables in Matlab or Octave?

I'm used to working in Matlab using its full GUI environment. Due to license issues I went and installed Octave, but it appears that it doesn't have a GUI, at least not one that's installed by default. I transferred the variables from Matlab to Octave by saveing them in Matlab and loading them in Octave. Thing is, I don't remember the...

Graph/tree representation and recursion.

Hey there, I'm currently writing an optimization algorithm in MATLAB, at which I completely suck, therefore I could really use your help. I'm really struggling to find a good way of representing a graph (or well more like a tree with several roots) which would look more or less like this: Basically 11/12/13 are our roots (stage 0), 2...

Octave / Matlab: Extend a vector making it repeat itself?

Hi everyone, Is there a way to extend a vector by making it repeat itself? >v = [1 2]; >v10 = v x 5; %x represents some function. Something like "1 2" x 5 in perl Then v10 would be: >v10 1 2 1 2 1 2 1 2 1 2 This should work for the general case, not just for [1 2] Thanks in advance ! ...

MATLAB: image corner coordinates & referncing to cell arrays

I am having some problems comparing the elements in different cell arrays. The context of this problem is that I am using the bwboundaries function in MATLAB to trace the outline of an image. The image is of a structural cross section and I am trying to find if there is continuity throughout the section (i.e. there is only one outline ...