Is it possible to save J results in some form other than a workspace?
Say some computations results in a large matrix and I want to export that
matrix to Mathematica.   How can I do it?   If I could write the matrix
as to a text file, great.  But what can I do with a workspace to make it
accessible to anything but J?

                thank you,
                David Cabana

   For example to write a noun from J you could use the following verb :

   Then ( x write <'b' ) writes x to filename b.

   And FYR, here is the counterpart to read which reads a textfile into J:

   So (z =. read 'textfile') makes z a character table in J (use ". to
   turn it into numbers).

 Most J programmers I know to don't use workspaces at all.
 However, a fellow name Mr. Frey wrote an article in VECTOR
 where he explains how workspaces can be used to provide
 object-oriented capabilities.

 If you have a lot of output and you want
 to organize your it so that it can be found with a key
 then you should check out MikePowell J programs for
 doing this or my C translation of his programs.

 Then you would want to write wrappers which convert Ma data
 structure into J's A struct, for when you are calling J from Ma, and visa
 versa, for when you are calling Ma from J. (Generally I would think it
 would be much more helpful to call Ma from J than visa versa.)  As far
 as learning the J structs is concerned, j.h and jt.h are about all you
 have to study.  If you want the names of the C programs which implement
 the primitive J verbs, then examine t.c.

 As to how do you do it. I recommend looking at the J-lapack interface
 at watserv1.waterloo.edu in languages/apl/j/workspaces (and there
 is an interface to vfftpack in the 1993.q2 archive).

 I recommend that you ftp to ftp.cs.ualberta.ca and get
 pub/smillie/intj.ps and intj.doc. This is paper provides a well
 written introduction to J for beginners.

 If you will be hacking the J source I suggest purchasing
 An Implementation of J.

 -emmett

tab=. 9{a.
lf=. 10{a.

cs=.{&('-',a.)&(('_',a.)&i.)

'cs' (I got from this newsgroup) converts j's '_' to '-'.
'clean' puts a tab after each numerical value in the array and
linefeeds at the beginning of each row.

Then I issue the following command "out =. }. , clean arrayname" to create
an output which can be written to a file. Then I use file write
"out (1!:2)  <'filename'" to actually write the file.

Maybe this will give you ideas.

--

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