| Re: How does REFORM work in PV-Wave [message #18077] |
Wed, 01 December 1999 00:00 |
jeyadev
Messages: 78
Registered: February 1995
|
Member |
|
|
In article <mgs-52612D.20571630111999@news.silcom.com>,
Mike Schienle <mgs@ivsoftware.com> wrote:
>
> You can probably find more than you wanted to know abot row and column
> order by visiting the IDL FAQ at <http://www.ivsoftware.com:8000/FAQ/>.
> Select the "Search FAQ" button. Enter the word "major" in the "Question"
> field and press the "Start Search" button. You'll be treated to a fairly
> detailed discussion on column- and row-major, as well as memory access
> into the arrays.
Found it, at last, by listing all the questions, but I know all *that*
stuff.
My question was what happens beyond 2 dimensions and how REFORM treats
a 2d to 3d coversion. I will simplify my question in the hope that some
kind soul will help me out.
Let us say that I have the data file
1 13
2 14
3 15
4 16
5 17
6 18
7 19
8 20
9 21
10 22
11 23
12 24
and that the first column represents data for a variable that is defined
on a 3 x 4 (i.e. 3 column and 4 rows) grid and the second column is for
another variable on the same grid. Assume that the data is stored in the
the array odat(2,12).
What is I want to do is the following: I want to create a 3 data array
with two planes of 3 x 4 elements so that each plane contains the the data
for one variable.
The REAL QUESTION: The command
data = reform(odat,2,3,4)
seems to do the job. For example
WAVE> a = data(0,*,*)
WAVE> info, a
A INT = Array(1, 3, 4)
WAVE> a = reform(a)
WAVE> info, a
A INT = Array(3, 4)
WAVE> print, a
1 2 3
4 5 6
7 8 9
10 11 12
which is exactly what I want. Now, what I would like to know is why the
number of planes (2) had to be the *first* index in the reform statement.
thanks
--
Surendar Jeyadev jeyadev@wrc.xerox.com
|
|
|
|
| Re: How does REFORM work in PV-Wave [message #18094 is a reply to message #18077] |
Tue, 30 November 1999 00:00  |
Mike Schienle
Messages: 37
Registered: May 1997
|
Member |
|
|
In article <8214p7$kcq$1@news.wrc.xerox.com>, jeyadev@wrc.xerox.com
wrote:
...
> I guess what I am missing is the *order* in which elements are stored.
> I think that PV-Wave stores 2d arrays in the 'row' format (first index
> varies fastest), but what about higher dimensional arrays?
You can probably find more than you wanted to know abot row and column
order by visiting the IDL FAQ at <http://www.ivsoftware.com:8000/FAQ/>.
Select the "Search FAQ" button. Enter the word "major" in the "Question"
field and press the "Start Search" button. You'll be treated to a fairly
detailed discussion on column- and row-major, as well as memory access
into the arrays.
Folks, as long as we're on the PV-WAVE subject, I have an old FAQ for
PV-WAVE that was done in 1995. It's at
<http://www.ivsoftware.com/pvwave_faq.html>. If someone would like to
take it over, drop me a line. If someone just wants to update it, I can
put it into the same format as the IDL FAQ and serve it from this site.
--
Mike Schienle Interactive Visuals, Inc.
mgs@ivsoftware.com Remote Sensing and Image Processing
http://www.ivsoftware.com/ Analysis and Application Development
|
|
|
|
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
