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  • how to build an accumulator array in matlab

    - by schwiz
    I'm very new to matlab so sorry if this is a dumb question. I have to following matrices: im = imread('image.jpg'); %<370x366 double> [y,x] = find(im); %x & y both <1280x1 double> theta; %<370x366 double> computed from gradient of image I can currently plot points one at a time like this: plot(x(502) + 120*cos(theta(y(502),x(502))),y(502) + 120*sin(theta(y(502),x(502))),'*b'); But what I want to do is some how increment an accumulator array, something like this: acc = zeros(size(im)); acc(y,x) = acc(x + 120*cos(theta(y,x)),y + 120*sin(theta(y,x)),'*b')) + 1; It would be nice if the 120 could actually be another matrix containing different radius values as well.

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  • Can I directly use JAVA-sourcecode directly in SCILAB, or Is there another way to connect both?

    - by Andreas Hornig
    Hi, a friend of mine uses SCILAB for doing his mathematicall "homework" for his studies and he told me, that it should be possible to use JAVA-sourcecode diretly in SCILAB. The background is that I presented my current JAVA project and I would like to plot this in 3d, but I haven't done graphical output so far. And he proposed to let SCILAB do the 3d plotting, because there are some ready to use plot scemes implented. But he couldn't tell me how to achive this, so that's why I'm here :). So my first question is, IF this is possible to directly use JAVA-Source code in SCILAB or at least to some kind of connection between both? And how this is done! :) Thank you in advance, Andreas

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  • R heatmaps - non-text labels?

    - by Carl
    I am making a heatmap plot; currently the axes are labeled by index number. However, the index number corresponds to a series of 1/0s, which my group typically represents with a row of filled(1) or unfilled(0) boxes (think chessboard, though not strictly alternating colors). I'd like to use that representation instead of the index numbers. Any suggestions? I've considered simply making the labels as a plot, and positioning that adjacent to the heatmap, but I'm not finding a convenient way to do that either. I will also appreciate answers that are more generically applicable. edit - current code: map <- data.matrix(read.csv("./heatmap.out", header=F, sep=" ")) # ...some clean-up p<-heatmap(map, Rowv=NA, Colv=NA, col=grey(10:0 / 10)) this simply labels the heatmap rows/cols by index number. heatmap.out is raw numeric data.

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  • Rotation Matrix calculates by column not by row

    - by pinnacler
    I have a class called forest and a property called fixedPositions that stores 100 points (x,y) and they are stored 250x2 (rows x columns) in MatLab. When I select 'fixedPositions', I can click scatter and it will plot the points. Now, I want to rotate the plotted points and I have a rotation matrix that will allow me to do that. The below code should work: theta = obj.heading * pi/180; apparent = [cos(theta) -sin(theta) ; sin(theta) cos(theta)] * obj.fixedPositions; But it wont. I get this error. ??? Error using == mtimes Inner matrix dimensions must agree. Error in == landmarkslandmarks.get.apparentPositions at 22 apparent = [cos(theta) -sin(theta) ; sin(theta) cos(theta)] * obj.fixedPositions; When I alter forest.fixedPositions to store the variables 2x250 instead of 250x2, the above code will work, but it wont plot. I'm going to be plotting fixedPositions constantly in a simulation, so I'd prefer to leave it as it, and make the rotation work instead. Any ideas? Also, fixed positions, is the position of the xy points as if you were looking straight ahead. i.e. heading = 0. heading is set to 45, meaning I want to rotate points clockwise 45 degrees. Here is my code: classdef landmarks properties fixedPositions %# positions in a fixed coordinate system. [x, y] heading = 45; %# direction in which the robot is facing end properties (Dependent) apparentPositions end methods function obj = landmarks(numberOfTrees) %# randomly generates numberOfTrees amount of x,y coordinates and set %the array or matrix (not sure which) to fixedPositions obj.fixedPositions = 100 * rand([numberOfTrees,2]) .* sign(rand([numberOfTrees,2]) - 0.5); end function obj = set.apparentPositions(obj,~) theta = obj.heading * pi/180; [cos(theta) -sin(theta) ; sin(theta) cos(theta)] * obj.fixedPositions; end function apparent = get.apparentPositions(obj) %# rotate obj.positions using obj.facing to generate the output theta = obj.heading * pi/180; apparent = [cos(theta) -sin(theta) ; sin(theta) cos(theta)] * obj.fixedPositions; end end end P.S. If you change one line to this: obj.fixedPositions = 100 * rand([2,numberOfTrees]) .* sign(rand([2,numberOfTrees]) - 0.5); Everything will work fine... it just wont plot.

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  • Help understanding how to make a bar chart using ggplot2

    - by celenius
    I'm trying to use the bar_geom function of ggplot2, but I can't understand how to use it. I've made a small sample of my code to show what I am trying to do: library(ggplot2) # sample data sampleData = data.frame( v1=c('a','b','c','d','e', 'f','g', 'h', 'i','j'), v2=c(1:10) ) sampleData$Names = data.frame( Names = paste(sampleData$v1, sampleData$v2, sep="") ) sampleData$Values = c(1:10) # make plot x = sampleData$Values y = sampleData$Names qplot( x, y, data = sampleData, geom="bar" ) I want sampleData$Names to be on the x-axis of my graph, labeling each bar and and sampleData$Values to scale the bar height. I want the y-axis to be specified as a range. I realize that I don't understand how ggplot2 functions as this small example does not work, yet my other example is generating a plot but I cannot specify a y-range as it considers the variables to be categorical.

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  • unevenly centered subplots in matplotlib in Python?

    - by user248237
    I am plotting a simple pair of subplots in matplotlib that are for some reason unevenly centered. I plot them as follows: plt.figure() # first subplot s1 = plt.subplot(2, 1, 1) plt.bar([1, 2, 3], [4, 5, 6]) # second subplot s2 = plt.subplot(2, 1, 2) plt.pcolor(rand(5,5)) # add colorbar plt.colorbar() # square axes axes_square(s1) axes_square(s2) where axes_square is simply: def axes_square(plot_handle): plot_handle.axes.set_aspect(1/plot_handle.axes.get_data_ratio()) The plot I get is attached. The top and bottom plots are unevenly centered. I'd like their yaxis to be aligned and their boxes to be aligned. If I remove the plt.colorbar() call, the plots become centered. How can I have the plots centered while the colorbar of pcolor is still shown? I want the axes to be centered and have the colorbar be outside of that alignment, either to the left or to the right of the pcolor matrix. image of plots link thanks.

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  • Variable alpha blending in pylab

    - by Hooked
    How does one control the transparency over a 2D image in pylab? I'd like to give two sets of values (X,Y,Z,T) where X,Y are arrays of positions, Z is the color value, and T is the transparency to a function like imshow but it seems that the function only takes alpha as a scalar. As a concrete example, consider the code below that attempts to display two Gaussians. The closer the value is to zero, the more transparent I'd like the plot to be. from pylab import * side = linspace(-1,1,100) X,Y = meshgrid(side,side) extent = (-1,1,-1,1) Z1 = exp(-((X+.5)**2+Y**2)) Z2 = exp(-((X-.5)**2+(Y+.2)**2)) imshow(Z1, cmap=cm.hsv, alpha=.6, extent=extent) imshow(Z2, cmap=cm.hsv, alpha=.6, extent=extent) show() Note: I am not looking for a plot of Z1+Z2 (that would be trivial) but for a general way to specify the alpha blending across an image.

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  • Matlab wont extract first row & column because of matrix dimensions !

    - by ZaZu
    Hey guys, I am tracking an object that is thrown in air, and this object governs a parabolic pattern. Im tracking the object through a series of 30 images. I managed to exclude all the background and keep the object apparent, then used its centroid to get its coordinates and plot them. Now im supposed to predict where the object is going to fall, so I used polyfit & polyval .. the problem is, matlab says ??? Index exceeds matrix dimensions. Now the centroid creates its own structure with a row and 2 columns. Everytime the object moves in the loop, it updates the first row only .. Here is part of the code : For N=1:30 . . . x=centroid(1,1); % extract first row and column for x y=centroid(1,2); % extract secnd row and column for x plot_xy=plot(x,y) set(plot_xy,'XData',x(1:N),'YData',y(1:N)); fitting=polyfit(x(1:N),y(1:N),2); parabola=plot(x,nan(23,1)); evaluate=polyval(fitting,x); set(parabola,'YData',evaluate) . . end The error message I get is ??? Index exceeds matrix dimensions. It seems that (1:N) is causing the problems .. I honestly do not know why .. But when I remove N, the object is plotted along with its points, but polyfitting wont work, it gives me an error saying : Warning: Polynomial is not unique; degree >= number of data points. > In polyfit at 72 If I made it (1:N-1) or something, it plots more points before it starts giving me the same error (not unique ...) . Any ideas why ?? Thanks alot !!

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  • GNUPlot: change axis labels

    - by Robert
    Dear Guys, I have used the following statement to get the GNUPlot plot a grah for me: plot "force.dat" using 1:2 title "Detroit" with lines, \ "force.dat" u 1:3 t "US Avergae" w linepoints and the "force.dat" looks like 2005 0 0 2006 104 51 2007 202 101 It draws nice graph for me. However, I don't like the X-axis, because it is labelled as 2005, 2005.5, 2006, 2006.5, 2007 etc.. However, those are year identifiers, I only want the 2005, 2006, 2007 etc., how could I get rid of the 2005.5, 2006.5 etc. labels in my GNUPlot graph? Thank you very much for your ideas.

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  • Audio Detection in Matlab

    - by insane-36
    I am writing a matlab code that would be able to read the audio file and then compare it to the another audio and recognize if those audio are the voice of the same person. In both type of the audio, would have the same word utterance and the audio is about 1 minutes long. I have come to know that the approach of sliding windows using hamming window would work best on this approach but have a very little idea on this. The simple code to read an audio file and then display a portion of 10s is as below : [x,fs, nbits]= wavread('01-AudioTrack 01.wav'); subplot(211) plot(x) title('Entire Wave') smallRange = 1:100000; subplot(212) plot(smallRange,x(smallRange)) How do I make Hamming window each of 10ms in this case and what approaches should I take to deal with this problem ?

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  • is there a way to get a "subtree" from hclust ? (R)

    - by Tal Galili
    Hello all, I wish to create a "subtree" from an hclust object. For example, let's say I have the following object: a <- list() # initialize empty object a$merge <- matrix(c(-1, -2, -3, -4, 1, 2, -5,-6, 3,4), nc=2, byrow=TRUE ) a$height <- c(1, 1.5, 3,4,4.5) # define merge heights a$order <- 1:6 # order of leaves(trivial if hand-entered) a$labels <- 1:6# LETTERS[1:4] # labels of leaves class(a) <- "hclust" # make it an hclust object plot(a) # look at the result Now I wish the extract from it the following subtree: a <- list() # initialize empty object a$merge <- matrix(c(-1, -2, -3, -4, 1, 2 ), nc=2, byrow=TRUE ) a$height <- c(1, 1.5, 3) # define merge heights a$order <- 1:4 # order of leaves(trivial if hand-entered) a$labels <- 1:4# LETTERS[1:4] # labels of leaves class(a) <- "hclust" # make it an hclust object plot(a) # look at the result How could I access it? (I know that cutree could get me the objects of the sub tree, but not create an actual hclust object) Thanks for any help, Tal

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  • R: ca plotting text attributes

    - by chasec
    Does anyone know of a way to control the font size/color/weight of the row and column names when plotting a correspondence plot with the ca package? The following code will produce a very nice looking chart, though if there were more attributes (very heavy, super heavy, something more than super heavy) or more classes of workers (peons, underlings, etc) then the graph will get a little cluttered and hard to tell what was what. It would be nice if you could list all the attributes in a separate color than the categories of workers. library(ca) data("smoke") plot(ca(smoke) , map = "symmetric" , what =c("active","active") , mass = c(T,T) , contrib = "absolute" , col = c("red","blue") , pch = c(15,17,15,17) , labels = c(2,2) , arrows = c(T,F) ) Alternatively, does anyone know if there is a way to reproduce something along these lines with ggplot2? I didn't find anything on the website that seemed comparable, but I don't know much about the package. Thanks, -Chase

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  • matplotlib: working with range in x-axis

    - by user324333
    Hey Guys, I'm trying to do a basic line graph here, but I can't seem to figure out how to adjust my x axis. And here is the error I get when I try adjusting my range. from pylab import * plot ( range(0,11),[9,4,5,2,3,5,7,12,2,3],'.-',label='sample1' ) plot ( range(0,11),[12,5,33,2,4,5,3,3,22,10],'o-',label='sample2' ) xlabel('x axis') ylabel('y axis') title('my sample graphs') legend(('sample1','sample2')) savefig("sampleg.png",dpi=(640/8)) show() File "C:\Python26\lib\site-packages\matplotlib\axes.py", line 228, in _xy_from_xy raise ValueError("x and y must have same first dimension") ValueError: x and y must have same first dimension I want my range to be a list of strings: ["12/1/2007","12/1/2008", "12/1/2009","12/1/2010"] Any suggestions?

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  • How can I manipulate the strip text of facet plots in ggplot2?

    - by briandk
    I'm wondering how I can manipulate the size of strip text in facetted plots. My question is similar to a question on plot titles, but I'm specifically concerned with manipulating not the plot title but the text that appears in facet titles (strip_h). As an example, consider the mpg dataset. library(ggplot2) qplot(hwy, cty, data = mpg) + facet_grid( . ~ manufacturer) The resulting output produces some facet titles that don't fit in the strip. I'm thinking there must be a way to use grid to deal with the strip text. But I'm still a novice and wasn't sure from the grid appendix in Hadley's book how, precisely, to do it. Also, I was afraid if I did it wrong it would break my washing machine, since I believe all technology is connected through The Force :-( Many thanks in advance.

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  • help with matlab and Discrete Fourier transform

    - by user504363
    Hi all I have previous experience with Matlab, but the problem that I face some problems in apply a problem in (DSP : Digital signal processing) which is not my study field, but I must finish that problems in days to complete my project. all i want is help me with method and steps of solving this problem in matlab and then I can write the code with myself. the problem is about the signal x(t) = exp(-a*t); 1) what's the Discrete Fourier transform of the sampled signal with sample rate fs 2) if a=1 and fs =1 , plot the amplitude spectrum of sampled signal 3) fix the sampling frequency at fs = 1(hz) [what's it mean ?] and plot the magnitude of the Fourier Transform of the sampled signal at various values of a thanks

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  • Changing ylim (axis limits) drops data falling outside range. How can this be prevented?

    - by Alex Holcombe
    df <- data.frame(age=c(10,10,20,20,25,25,25),veg=c(0,1,0,1,1,0,1)) g=ggplot(data=df,aes(x=age,y=veg)) g=g+stat_summary(fun.y=mean,geom="point") Points reflect mean of veg at each age, which is what I expected and want to preserve after changing axis limits with the command below. g=g+ylim(0.2,1) Changing axis limits with the above command unfortunately causes veg==0 subset to be dropped from the data, yielding "Warning message: Removed 4 rows containing missing values (stat_summary)" This is bad because now the data plot (stat_summary mean) omits the veg==0 points. How can this be prevented? I simply want to avoid showing the empty part of the plot- the ordinate from 0 to .2, but not drop the associated data from the stat_summary calculation.

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  • numpy array C api

    - by wiso
    I have a C++ function returning a std::vector and I want to use it in python, so I'm using the C numpy api: static PyObject * py_integrate(PyObject *self, PyObject *args){ ... std::vector<double> integral; cpp_function(integral); // this change integral npy_intp size = {integral.size()}; PyObject *out = PyArray_SimpleNewFromData(1, &size, NPY_DOUBLE, &(integral[0])); return out; } when I call it from python, if I do import matplotlib.pyplot as plt a = py_integrate(parameters) print a fig = plt.figure() ax = fig.add_subplot(111) ax.plot(a) print a the first print is ok, the values are correct, but when I plot a they are not, and in particular in the second print I see very strange values like 1E-308 1E-308 ... or 0 0 0 ... as an unitialized memory. I don't understand why the first print is ok.

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  • Using polyfit to predict where the object falls ?

    - by ZaZu
    Hi there, I have information of an object being thrown at a parabolic pattern. There are 30 images in total taken at specific intervals from the start position till the end. Now I have managed to extract the x,y coordinates of the object being thrown in all 30 images... I think that using polyfit (or maybe polyval ? ) may help me predict where the object will fall after the first 15 images ... I just want to know, how can polyfit be used with the 30 x,y coordinates I have ? ( I have a loop to extract each image from a mat file 1 row at a time until 30 .. and then plot that image .. so should I use polyfit in the same loop before/after the plot ??? Any ideas ?? Thanks !

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  • a small question on GNUPlot

    - by Robert
    Dear Guys, I have used the following statement to get the GNUPlot plot a grah for me: plot "force.dat" using 1:2 title "Detroit" with lines, \ "force.dat" u 1:3 t "US Avergae" w linepoints and the "force.dat" looks like 2005 0 0 2006 104 51 2007 202 101 It draws nice graph for me.However,I don't like the X-axis,because it is labelled as 2005,2005.5,2006,2006.5,2007..etc. However,those are year identifiers,I only want the 2005,2006,2007 etc,how could I get rid of the 2005.5,2006.5 etc labels in my GNUPlot graph? Thank you very much for your ideas.

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  • What's the fastest way to approximate the period of data using Octave?

    - by John
    I have a set of data that is periodic (but not sinusoidal). I have a set of time values in one vector and a set of amplitudes in a second vector. I'd like to quickly approximate the period of the function. Any suggestions? Specifically, here's my current code. I'd like to approximate the period of the vector x(:,2) against the vector t. Ultimately, I'd like to do this for lots of initial conditions and calculate the period of each and plot the result. function xdot = f (x,t) xdot(1) =x(2); xdot(2) =-sin(x(1)); endfunction x0=[1;1.75]; #eventually, I'd like to try lots of values for x0(2) t = linspace (0, 50, 200); x = lsode ("f", x0, t) plot(x(:,1),x(:,2)); Thank you! John

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  • problems with matlab wavrecord and wavread

    - by user504363
    Hi all I have a problem in matlab I want to record a speech for 2 seconds then read the recorded sound and plot it I use the code FS = 8000; new_wav = wavrecord(2*FS,FS,'int16'); x = wavread(new_wav); plot(x); but the error appears ??? Error using ==> fileparts at 20 Input must be a row vector of characters. Error in ==> wavread>open_wav at 193 [pat,nam,ext] = fileparts(file); Error in ==> wavread at 65 [fid,msg] = open_wav(file); Error in ==> test at 2 x = wavread(new_wav); I plotted correctly recorded sound files, but when I want to record new one through matlab I get this errors. I tried many ways by changing FS and 'int16' but nothing happens. thanks

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  • How to create plots in multiple windows and keep them seperate in R

    - by PaulHurleyuk
    Hello SOers, I'm sure this is an easy problem, but my google / help foo has failed me, so it's up to you. I have an R script that generates several plots, and I want to view all the plots on screen at once (in seperate windows), but I can't work out how to open multiple graphics windows. I'm using ggplot2, but I feel this is a more basic problem, so I'm just using base grapics for this simple example x<-c(1:10) y<-sin(x) z<-cos(x) dev.new() plot(y=y,x=x) dev.off() dev.new() plot(x=x,y=z) But this doesn't work. I'm on Windows if this matters (Windows + Eclipse + StatEt)

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  • gnuplot - multiple lines with different x ranges

    - by Aly
    Hi, I am using gnuplot to try and plot several lines but each have different x ranges. I am running the following script: # gnuplot script for 'omarConf2EvONLY-vs-everyone-gta-lag-lpas-omarConf1-random-tag-tpas.dat' plot "omarConf2EvONLY-vs-everyone-gta-lag-lpas-omarConf1-random-tag-tpas.dat" using 1:2 with lines title '1' replot "omarConf2EvONLY-vs-everyone-gta-lag-lpas-omarConf1-random-tag-tpas.dat" using 1:3 with lines title '2' replot "omarConf2EvONLY-vs-everyone-gta-lag-lpas-omarConf1-random-tag-tpas.dat" using 1:4 with lines title '3' replot "omarConf2EvONLY-vs-everyone-gta-lag-lpas-omarConf1-random-tag-tpas.dat" using 1:5 with lines title '4' replot "omarConf2EvONLY-vs-everyone-gta-lag-lpas-omarConf1-random-tag-tpas.dat" using 1:6 with lines title '5' replot "omarConf2EvONLY-vs-everyone-gta-lag-lpas-omarConf1-random-tag-tpas.dat" using 1:7 with lines title '6' replot "omarConf2EvONLY-vs-everyone-gta-lag-lpas-omarConf1-random-tag-tpas.dat" using 1:8 with lines title '7' set terminal png size 800,600 set output "omar_vs_everyone-EVONLY.png" replot and the .dat file is just a file with columns such as: 1 0.5 0.5 0.1 2 0.6 1.3 0.8 3 0.7 0.32 4 0.7 0.35 5 1.3 4.32 6 1.67 notice that the columns have different lengths as each line has different x ranges. The problem I have is that it plots funny as shown below:

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  • Statistics Question: Kernel Smoothing in R

    - by James Thompson
    I have data of this form: x y 1 0.19 2 0.26 3 0.40 4 0.58 5 0.59 6 1.24 7 0.68 8 0.60 9 1.12 10 0.80 11 1.20 12 1.17 13 0.39 I'm currently plotting a kernel-smoothed density estimate of the x versus y using this code: smoothed = ksmooth( d$resi, d$score, bandwidth = 6 ) plot( smoothed ) I simply want a plot of the x versus smoothed(y) values, which is ## Heading ## However, the documentation for ksmooth suggests that this isn't the best kernel-smoothing package available: This function is implemented purely for compatibility with S, although it is nowhere near as slow as the S function. Better kernel smoothers are available in other packages. What other kernel smoothers are better can these smoothers be found?

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  • Save/Load jFreechart TimeSeriesCollection chart from XML

    - by IMAnis_tn
    I'm working with this exemple wich put rondom dynamic data into a TimeSeriesCollection chart. My problem is that i can't find how to : 1- Make a track of the old data (of the last hour) when they pass the left boundary (because the data point move from the right to the left ) of the view area just by implementing a horizontal scroll bar. 2- Is XML a good choice to save my data into when i want to have all the history of the data? public class DynamicDataDemo extends ApplicationFrame { /** The time series data. */ private TimeSeries series; /** The most recent value added. */ private double lastValue = 100.0; public DynamicDataDemo(final String title) { super(title); this.series = new TimeSeries("Random Data", Millisecond.class); final TimeSeriesCollection dataset = new TimeSeriesCollection(this.series); final JFreeChart chart = createChart(dataset); final ChartPanel chartPanel = new ChartPanel(chart); final JPanel content = new JPanel(new BorderLayout()); content.add(chartPanel); chartPanel.setPreferredSize(new java.awt.Dimension(500, 270)); setContentPane(content); } private JFreeChart createChart(final XYDataset dataset) { final JFreeChart result = ChartFactory.createTimeSeriesChart( "Dynamic Data Demo", "Time", "Value", dataset, true, true, false ); final XYPlot plot = result.getXYPlot(); ValueAxis axis = plot.getDomainAxis(); axis.setAutoRange(true); axis.setFixedAutoRange(60000.0); // 60 seconds axis = plot.getRangeAxis(); axis.setRange(0.0, 200.0); return result; } public void go() { final double factor = 0.90 + 0.2 * Math.random(); this.lastValue = this.lastValue * factor; final Millisecond now = new Millisecond(); System.out.println("Now = " + now.toString()); this.series.add(new Millisecond(), this.lastValue); } public static void main(final String[] args) throws InterruptedException { final DynamicDataDemo demo = new DynamicDataDemo("Dynamic Data Demo"); demo.pack(); RefineryUtilities.centerFrameOnScreen(demo); demo.setVisible(true); while(true){ demo.go(); Thread.currentThread().sleep(1000); } } }

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