[Swift-devel] mappers on files that are inputs and outputs

[Ben Clifford]

Here's a code fragment:

  type volume {
      imagefile img;
      headerfile hdr;
  };

  volume atlas <simple_mapper;prefix="atlas">;
  atlas = softmean(slices);

  string directions[] = [ "x", "y", "z"];

  foreach direction in directions {
      giffile outputgif 
          <single_file_mapper;file=@strcat("atlas-",direction,".gif")>;
      string option = @strcat("-",direction);
      outputgif = slice_to_gif(atlas, option, ".5");
  }

When this is run as part of a workflow, there are no atlas.* files and the 
atlas = softmean(slices) line causes atlas.hdr and atlas.img files to be 
created and placed in my working directory, and also used in the 
subsequent slice_to_gif calls.

If I prune the program in a text editor so that the altas = ... line is 
not called, and leave the atlas.hdr and atlas.img files in place in my 
current directory (so that the files are now input files, rather than 
intermediate files), I get this error:

  $ swift -debug -tc.file tc.data play.swift 
  WARN   - Failed to configure log file name

  Swift v0.1-dev

  RunID: mx49u8a36d1m0
  Execution failed:
          java.lang.RuntimeException: Data set initialization failed for 
  true. Missing required field: img mapped to atlas


I think its probably a desirable feature that the same mapping that maps 
ok for intermediate files to map for input files too.

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