.TH "diststream" 2rheolef "Version 7.2" "rheolef" \" -*- nroff -*-
.ad l
.nh
.SH NAME
diststream \- i/o streams in distributed environment (rheolef-7\&.2)
.PP
 
.SH "DESCRIPTION"
.PP
The \fCidiststream\fP and \fCodiststream\fP classes provide a stream input and output interface for parallel and distributed codes\&. The main difference Recall that, with the usual \fCstd::istream\fP and \fCstd::ostream\fP, any i/o operation are executed on all processes: e\&.g\&. the output is printed many times\&. In contrast, \fCidiststream\fP and \fCodiststream\fP manage nicely the distributed environment\&.
.PP
For small data, e\&.g\&. \fCint\fP, \fCdouble\fP or \fCstring\fP, a specific processor is selected for i/o operations\&. For large data, the i/o operations are delegated to a specific class member functions when available\&.
.PP
For convenience, the standard streams \fCcin\fP, \fCcout\fP, \fCclog\fP and \fCcerr\fP are extended as \fCdin\fP, \fCdout\fP, \fCdlog\fP and \fCderr\fP, respectively\&.
.SH "FILE SUFFIXES"
.PP
Finally, optional suffix extension to the file name is automatically handled: 
.PP
.nf
    odiststream foo('NAME', 'suffix');

.fi
.PP
 is similar 
.PP
.nf
    ofstream foo('NAME\&.suffix')\&.

.fi
.PP
 Conversely, 
.PP
.nf
    irheostream foo('NAME','suffix');

.fi
.PP
 is similar to 
.PP
.nf
    ifstream foo('NAME\&.suffix')\&.

.fi
.PP
 
.SH "FILE SEARCH"
.PP
Recursive search in a directory list is provided for finding the input file\&. However, we look at a search path environment variable \fCRHEOPATH\fP in order to find \fCNAME\fP while the suffix is assumed\&. Moreover, \fCgzip\fP compressed files, ending with the \fC\&.gz\fP suffix are handled, and decompression is done automatically on the fly in that case\&.
.SH "COMPRESSION"
.PP
File compression/decompresion is handled on the fly, thanks to the \fCgzip\fP library\&. The data compression is assumed by default for output: it can be deactivated while opening a file by an optional argument: 
.PP
.nf
    odiststream foo('NAME', 'suffix', io::nogz);

.fi
.PP
 
.SH "APPEND MODE"
.PP
An existing file, possibly compressed, can be reopen in \fCappend\fP mode\&. New results will be appended at the end of an existing file: 
.PP
.nf
    odiststream foo('NAME', 'suffix', io::app);

.fi
.PP
 
.SH "FLUSH"
.PP
The \fCflush\fP member function is nicely handled in compression mode: this feature allows intermediate results to be available during long computations\&. Buffers are flushed and data are available in the output file\&.
.SH "IMPLEMENTATION"
.PP
This documentation has been generated from file linalg/lib/diststream\&.h
.PP
.PP
.nf
class idiststream {
public:
  typedef std::size_t size_type;

// allocators/deallocators:
     
  idiststream();
  idiststream (std::istream& is, const communicator& comm = communicator());
  idiststream (std::string filename, std::string suffix = "",
             const communicator& comm = communicator());
  ~idiststream();

// modifiers:

  void open (std::string filename, std::string suffix = "",
             const communicator& comm = communicator());
  void close();

// accessors:

  const communicator& comm() const { return _comm; }
  bool good() const;
  operator bool() const { return good(); }
  static size_type io_proc();
.fi
.PP
 
.PP
.nf
};

.fi
.PP
 
.PP
.nf
class odiststream {
public:
  typedef std::size_t size_type;

// allocators/deallocators:

  odiststream();
  odiststream (std::string filename, std::string suffix = "",
              io::mode_type mode = io::out, const communicator& comm = communicator());
  odiststream (std::string filename,
              io::mode_type mode, const communicator& comm = communicator());
  odiststream (std::string filename, std::string suffix, const communicator& comm);
  odiststream (std::string filename, const communicator& comm);
  odiststream(std::ostream& os, const communicator& comm = communicator());
  ~odiststream();

// modifiers:

   void open (std::string filename, std::string suffix = "",
             io::mode_type mode = io::out, const communicator& comm = communicator());
   void open (std::string filename, 
             io::mode_type mode, const communicator& comm = communicator());
   void open (std::string filename, std::string suffix,
             const communicator& comm);
   void open (std::string filename, const communicator& comm);
   void flush();
   void close();

// accessors:

   const communicator& comm() const { return _comm; }
   bool good() const;
   operator bool() const { return good(); }
   static size_type io_proc();

.fi
.PP
 
.PP
.nf
};

.fi
.PP
 
.SH AUTHOR
Pierre  Saramito  <Pierre.Saramito@imag.fr>
.SH COPYRIGHT
Copyright   (C)  2000-2018  Pierre  Saramito  <Pierre.Saramito@imag.fr>
GPLv3+: GNU GPL version 3 or later  <http://gnu.org/licenses/gpl.html>.
This  is  free  software:  you  are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.