Re: InFile

[Pietro Terna]

        Thanks a lot, Pietro

At 16.01 11/09/99 -0700, you wrote:
>>>>>> "PT" == Pietro Terna <address@hidden> writes:
>
>PT>    Reading the documentation I see that InFile and OutFile
>PT> protocol are now deprecated.
>
>PT>    What is the easy alternative? My need is to read and write the
>PT> contents of some arrays of float.
>
>I suggest you use either the Lisp or HDF5 archivers.  (FYI, InFile and
OutFile
>won't go away any time soon for Objective C users.)
>
>Suppose you have a floating point matrix in a file like below that you
>want to load into a Swarm object.
>
>$ cat ary.txt
>1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0
>10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.0
>
>The first thing to do it to convert this data into a format Swarm can load. 
>Swarm currently knows about two formats: a Scheme-like format and HDF5.
>
>To create HDF5 for Swarm, the procedure to load this file involves running 
>a script in R like this:
>
>$ cat saveary.R
>v <- scan("ary.txt") # load vector of data
>m <- matrix(v, nrow=2,byrow=TRUE) # convert vector to array
>myObject <- list(ary=m) # wrap array in an object
>attr(myObject,"type") <- "MyObject" # identify as a MyObject class (for
Swarm)
>hdf5save("ary.hdf",myObject) # save it to HDF5
>
>Which you can run like this:
>
>$ R BATCH saveary.R
>
>The result is the file ary.hdf (not itself human-readable).  Note that
>HDF5 is a standalone library that has a well-defined API; it's not
>necessary to use R if you have another tool or application that makes
>calls to the HDF5 library.
>
>Here is what the text file above would look like converted to Scheme:¹
>
>$ cat ary.scm
>(list
> (cons 'myObject
>       (make-instance 'MyObject 
>                      #:ary
>                      #2((1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0) 
>                         (10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0
100.0))
>                      )))
>
>This format is list of pairs where the first member of the pair
>(a.k.a. a "cons") is a key the the second is a value.  The key,
>"myObject" is the name you give to the object (an instance of MyObject
>that contains an array).
>
>Once you've created either ary.hdf or ary.scm, then you can use either
>the HDF5Archiver or LispArchiver to load it.  The crucial thing to
>look at in the program below are the "#ifdef USE_HDF5" alternatives and
>the call to getObject: that follows.
>
>#import <simtools.h>
>#import <defobj/Create.h>
>#import <defobj.h>
>
>#define ROWS 2
>#define COLUMNS 10
>
>@interface MyObject: CreateDrop
>{
>  double ary[ROWS][COLUMNS];
>}
>@end
>
>@implementation MyObject
>- (void)describe: outputCharStream
>{
>  unsigned i;
>
>  for (i = 0; i < ROWS; i++)
>    {
>      unsigned j;
>
>      for (j = 0; j < COLUMNS; j++)
>        printf (" %f", ary[i][j]);
>      putchar ('\n');
>    }
>}
>@end
>
>@interface Controller: CreateDrop
>{
>  id ary;
>}
>+ createBegin: aZone;
>@end
>
>@implementation Controller
>
>+ createBegin: aZone
>{
>  Controller *obj = [super createBegin: aZone];
>
>  obj->ary = [MyObject create: globalZone];
>  return obj;
>}
>
>@end
>
>int
>main (int argc, const char **argv) 
>{
>
>  initSwarmBatch (argc, argv);
>
>  {
>    id archiver;
>    id controller;
>
>#ifdef USE_HDF5
>    archiver = [[[HDF5Archiver createBegin: globalZone]
>                  setPath: "ary.hdf"]
>                 createEnd];
>#else
>    archiver = [[[LispArchiver createBegin: globalZone]
>                  setPath: "ary.scm"]
>                 createEnd];
>#endif
>    
>    xprint ([archiver getObject: "myObject"]);
>    controller = [Controller create: globalZone];
>  }
>  return 0;
>}
>
>/*
>Local Variables:
>compile-command: "$SWARMHOME/bin/libtool-swarm --mode=link gcc -DUSE_HDF5
-o ary -g -Wno-import -I$SWARMHOME/include -L$SWARMHOME/lib ary.m -lswarm
-lobjc"
>End:
>*/
>
>
>
>¹ Instead reformatting by hand, you can also use program to do it for you.
>Here's a Scheme program that converts a text file to the right Scheme format.
>
>$ cat convert-ary.sc
>(define (load-text text-file)
>    (with-input-from-file text-file
>      (lambda ()
>        (let join-strings ((expr ""))
>             (let ((line (read-line)))
>               (if (eof-object? line)
>                   (call-with-input-string (string-append "#2(" expr ")")
>                                           read)
>                   (join-strings (string-append expr "(" line ")"))))))))
>
>(define (wrap filename ary)
>    (with-output-to-file filename
>      (lambda ()
>        (write `(list
>                 (cons 'myObject
>                  (make-instance 'MyObject #:ary ,ary)))))))
>
>$ guile -l convert-ary.scm -c '(wrap "ary.scm" (load-text "ary.txt"))'
>
>
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