ESM4714
Scientific Visual Data Analysis and Multimedia

Assignment #5:
Glyph Representation of Eigenvalue Problems

Due: one week for the day it was assigned


Part I (100pts):
Generate three different ellipsoid glyphs

GIVEN: Exercise#10: Examples of a rotating cube ("box") and tetrahedron glyphs written with PV-Wave procedure files. Also there is a FORTRAN program for generating vertices and polygon files and several PV-Wave procedure files that read the vertices and polygon files which are then used to generate the shaded surface glyphs. The procedure files that rotate these shaded glyphs give the viewer's "mind's eye" an opportunity to view the third dimension. These files are located in the directory /optical/ESM4714/examples/poly/sphere on your optical disk. Study the maketp.f FORTRAN program, listed below, which you will need to modify in this assignment to include a subroutine function that varies the radius as a function of dimensions: a,b and c and angles: phi and theta. A schematic figure showing these geometrical glyph parameters is also provided in the class handout that will help you understand how to modify the maketp.f program to include the case when a, b, c, are not all equal to the radius.

FORTRAN program maketp.f
____________________________________________________________________________
Program maketp
open(6,file='maketp.out',status='unknown',err=8888)
open(7,file='vert.dat',status='unknown',err=8888)
open(8,file='poly.dat',status='unknown',err=8888)
comment: set geometric parameters
nphi=9
rphi=360.0
ntheta=9
rtheta=180.0
comment: comment out statement radius=1.0 (radius of a sphere)
pi=acos(-1.)
dthetar=(rtheta/(ntheta-1))*pi/180.0
dphir=(rphi/(nphi-1))*pi/180.0
comment: start do loops
ivert=0
phir=0.0
do 200 iphi=1,nphi
thetar=0.0
do 100 itheta=1,ntheta
comment: modify the radius where "e" is a function of phir,thetar,a,b,c
radius=e(phir,thetar,a,b,c)
comment:
vert1=radius*sin(thetar)*cos(phir)
vert2=radius*sin(thetar)*sin(phir)
vert3=radius*cos(thetar)
write(7,250)vert1,vert2,vert3
(etc.)

CONSTRUCT: a glyph of an ellipsoid with three different axes corresponding to the three eigenvalues a,b,c: (a,b,c)=(1.0,1.0,1.0), (5.0,1.0,1.0), (1.0,2.0,3.0). Make a PV-Wave procedure file for each of the three cases where the glyph rotates 360 degrees similar to the sphere example.

POST YOUR RESULTS
Logon to username: homework, password: to be handed out in class. Create a directory with your lastname: (~homework/assign#5/lastname).

Put a copy of your files, lastname.pro , in your lastname directory. Also put a copy of a text file lastname.txt with your comments on homework assignment#5. Print a copy of your files and also hand these copies in at class on the due date.

Your grade will be based on your observations and conclusions in addition to how well your procedure files work when I rotate your three glyphs. In other words, how clearly can I see the three eigenvalues ("visual display of quantitative information": physics) as the glyph rotates. Your grade will not be based on your programming skills although brevity, clarity, and meaningful comment statements will be appreciated as I review your procedure files.


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Ronald D. Kriz
College of Engineering
Virginia Tech
Revised 01/10/99

http://www.sv.vt.edu/classes/ESM4714/Assign/assign5.html