Post-13

• Review all of Modules 15, 16, and 17.

• Complete in-class exercises 1-20 in Module 15, and 1-11 in Module 16, and 1-4 in Module 17. Don't forget to upload these in BB.

• In this part of the assignment, you will write a program called StarPlot.java. to, well, plot some stars and constellations. In doing so, you will get some practice in reading data from files.

  Let's start with the file stardata.txt (which you should download and save to the same directory where you are going to write StarPlot. The file has data for 3,526 stars labelled from 0 to 3525, with the data for each star on a single line. Here, for example, are the first 10 lines of the file:

  0 0.994772 0.023164 4.61 
  1 0.97249 0.024187 5.55 
  2 0.435119 0.012234 5.57 
  3 0.998442 0.033711 6.43 
  4 0.998448 0.035746 6.18 
  5 0.873265 0.031968 2.07 ALPHERATZ
  6 0.512379 0.020508 2.28 CAPH; CAS BETA
  7 0.949168 0.037455 5.57 
  8 0.882312 0.036017 5.42 
  9 0.69724 0.028641 3.88 
  

  Each line has four numbers and possibly a name that follows. The first number is the ID of the star, the second and third are (x,y) coordinates, and the fourth is the star's magnitude. In the first part of this assignment, you are to read this data from the file and plot the stars with the right magnitude.

  You'll need to use DrawTool, set the XY range to be [-1,1], set the background color to be black, and the point color to be white. (Later, we'll use yellow for the constellation lines.) You might be asking ... why isn't there a Z coordinate since stars are in 3D space? This is because the view has been simplified to plot a 2D view of the sky.

  The one number that needs some explanation is the magnitude. Somewhat counter-intuitively, the smaller the number, the brighter the star. Thus, you should draw a larger point for a brighter star, a smaller one for a less-bright star. You can set the size of a point in the new version of DrawTool. What you'll need to do is come up with a rule to convert the given magnitude (which ranges from -1.44 to 10.5) to a point size so that the brightest star (with magnitude -1.44) is largest. If you're curious about why this sort of "upside down" scale is used, read about it here.

• The three files cassiopeia.txt, bigdipper.txt, and ursaminor.txt represent three well-known constellations. For example, let's take a look at the Big Dipper:

  2032 1987 
  1987 1929 
  1929 1813 
  1813 1778 
  1778 1687 
  1687 1690
  1813 1690
  

  Each line has two numbers, and each number is a star ID. Thus, the two numbers 2032, 1987, on a line represent a straight line to be drawn from the star with ID 2032 to the star with ID 1987. Draw these lines in yellow. Add your code for this part to StarPlot in a separate method called plotConstellation with the following signature

    static void plotConstellation (String filename, double[] x, double[] y)
    {
        // Read the data from the given file
        // and plot the constellation using yellow lines.
    }
  

  that, after plotting the stars, reads the given constellation's data and plots the lines corresponding to the constellation. Then, in main you can call this method three times for the three constellations.

• In an earlier Post, you wrote a program called Diagonal.java with a nested for-loop to print this output:

       5
      4
     3
    2
   1
  

  Note: there are five spaces before the 5, four spaces before the 4, ... etc. Change that program to use nested while-loops. Call your new program DiagonalWithWhile.java

Recommended, but not required: This week's theme: neurocomputing

• See this video on how a more brain-like computing device could be built.
• See this video on a project that seeks to simulate a real brain on a computer.