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MathGroup Archive 1996

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TRYING to read ASCII data with Mathematica

  • Subject: [mg3079] TRYING to read ASCII data with Mathematica
  • From: mek at guinan.arl.psu.edu (Mark E. Kotanchek)
  • Date: 30 Jan 1996 05:04:25 -0600
  • Approved: usenet@wri.com
  • Distribution: local
  • Newsgroups: wri.mathgroup
  • Organization: Penn State University, Center for Academic Computing
  • Sender: daemon at wri.com

(Apologies for posting this here rather than *.soft-sys.*; however, I was 
hoping for a quick response before I lose the few remaining hairs on my 
scalp.)

I have some sizable data files (>40MB) to which I'd like to apply some 
subspace processing algorithms. Alas, Mma is being quite adament about not 
letting me load the data in reasonable segments and, thereby, avoid running 
out of memory. I've been trying various permutations and currently have "the 
bible", Shaw&Tigg, Blachman's Quick Refernce, Gray's Mastering Mathematica, 
and Gayloard's Programming w/ Mma open on my desk as well as the function 
browser. After all that, I have no idea as to why I cannot achive my 
objective -- other than to assume some innate malevolence in Mma 2.2 when 
running under NEXTSTEP 3.3/Intel.

That said, I have one small (2 MB) file I've been using as a test case and 

   In[75]:=
      !!test15.mts

yields the correct response of a three column by umpteen row ascii response:

   97.957191	-1.1539974	-9207.8301
   97.967194	-1.1536527	-8654.8857
   97.977196	-1.1431384	-3954.8635
   97.98719	-1.1343479	-997.78583
   97.997192	-1.142449	-4124.4697
   :

After some fussing, I discovered that 

   ReadList[deflectionFile,Real,
   	RecordLists -> True,
   	RecordSeparators -> {"\r"}]

will read in the file. Alas, I cannot (nor, do I want to) handle the entire 
file in one humongous chunk. Thus, we try the approach...

   In[43]:=
      strm = OpenRead[deflectionFile]
      Read[strm,Real]
      Read[strm,Real]
      Read[strm,Real]
      Read[strm,Real]
      Close[strm]
   
   Out[43]=
      InputStream[test15.mts, 9]
   Out[44]=
      97.957191
   Out[45]=
      -1.1539974
   Out[46]=
      -9207.8301
   Out[47]=
      EndOfFile
   Out[48]=
      test15.mts
   
along with the error message:

   From In[43]:=
      Read::readn: Syntax error reading a real number from test15.mts.
   
Trying various options for RecordSeparators, etc. doesn't seem to do anything 
positive. I don't think what I'm trying to should be all that difficult; 
however, after fussing for three hours at what should be a trivial task I'm 
at wits end. Maybe I've just run into a "feature" of the NEXTSTEP/Intel 
version of Mma? (I hear a bug-fix version should be out in August!!)

Thanks for any help,

Mark.
-- 
Dr. Mark Kotanchek
Signal Processing Dept - 363 ASB
Applied Research Lab/Penn State
P.O. Box 30
State College, PA 16804

e-mail:	kotanchek at psu.edu (NeXTmail, MIME-mail)
TEL:	(814)863-0682
FAX:	(814)863-0753


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