roskar@jhunix.HCF.JHU.EDU (Veljko Roskar) (09/29/90)
I am in dire need of help with Mathematica's 3D surface plotting
feature. I am a novice user of this impressive package and am also
finishing a Master's thesis in chemical engineering.
I would like to fit a surface to my data, where the third variable
is a function of the first two. Not just to impress my advisor,
but to really show what's going on as conditions change!
Fitting a second order polynomial while keeping one variable
constant was easy, but the Mathematica book is vague about 3D
surface fitting and plotting the results (I can plot my data
points in 3D
using the Table[Point[{}]] and Show[Graphics3D[%]] functions).
The other problem is reading my data from a (Mac) TAB delimited
text file. But if someone could help me with the first problem,
I can enter the data by hand, because I have to have this done
FAST!
This is what my data looks like, the third variable is a function
of the first two:
co1=List[{.807,1.0,22.84},{.575,1.0,12.36},{.417,1.0,7.43},{.267,1
.0,3.44},{0,1.0,1.23}]
co2=List[{.807,1.1,24.41},{.575,1.1,13.82},{.417,1.1,8.40},{.267,1
.1,3.85},{0,1.1,1.27}]
co3=List[{.807,1.2,25.97},{.575,1.2,15.29},{.417,1.2,9.37},{.267,1
.2,4.26},{0,1.2,1.31}]
co4=List[{.807,1.3,27.54},{.575,1.3,16.75},{.417,1.3,10.3},{.267,1
.3,4.67},{0,1.3,1.35}]
Note that the first variable repeats itself in every "co#" set,
and that the second one is constant in each set.
What kind of a Fit[{}] should I have? How do I combine the fits
for each "co#" curve to make a surface? Or should I enter the
variables in an array and do a direct surface fit from there?
And finally (if you had this much patience), how do I use the
Show[Graphics3D[]] function with the fitted surface. Is it
possible to show the points on the same graph also?
Boundless thanks for any help. Please send replies and I'll post
a summary.
Best regards,
--
Veljko Roskar | roskar@jhuvms.bitnet
Department of Chemical Engineering | roskar@jhuvms.hcf.jhu.edu
The Johns Hopkins University, Baltimore | uunet!mimsy!aplcen!jhunix!roskar