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GETNTYPE(2)		      LAM NETWORK LIBRARY		   GETNTYPE(2)

NAME
       getnodeid, getnodetype, getorigin, getncomp, getnotb, getnall, getntype
       - Get information on LAM nodes.

SYNOPSIS
       #include <net.h>

       int getnodeid ();
       int getnodetype ();
       int getorigin ();

       int getnall ();
       int getncomp ();
       int getnjones ();
       int getnotb ();
       int getntype (int nodetype, int typemask);

FORTRAN SYNOPSIS
       integer function IGNDID ()
       integer function IGNDTP ()
       integer function IGORGN ()

       integer function IGNALL ()
       integer function IGNCMP ()
       integer function IGNJON ()
       integer function IGNOTB ()
       integer function IGNTP (nodetype, typemask)

       integer nodetype, typemask

DESCRIPTION
       These functions return node information obtained from the  local	 route
       daemon,	a modular component of the LAM daemon, regarding the currently
       running LAM network.  A node is defined by its identifier, an arbitrary
       32 bit value, and its type, a combination of flags describing the capa‐
       bilities of the node.  These flags (see	CONSTANTS(5)  and/or  <net.h>)
       are:

       NT_ITB	   node running LAM natively

       NT_CAST	   node multicast, a group of nodes

       NT_WASTE	   node not part of main computing group

       NT_DISK	   node has a disk

       NT_TUBE	   node has a video display unit

       NT_JONES	   node is a neighbour of the local node

       NT_BOOT	   node is booted by the local node

       getnodeid()  returns  the local node identifier.	 getnodetype() returns
       the local node type.  getorigin() returns the origin  node  identifier,
       from which LAM was booted.

       getncomp()  returns  the number of nodes marked for the "main" computa‐
       tion.  A typical application will use most (maybe all) of the nodes  in
       a parallel machine to compute portions of decomposed data.  Programmers
       frequently need to know the number of  these  "compute"	nodes.	 Other
       nodes  may be present in the multicomputer to handle peripherals or se‐
       quential portions of an application.

       getnotb() returns the total number of OTB nodes.	 getnall() returns the
       total  number of nodes in the system.  getnjones() returns the caller's
       number of neighbour (directly connected) nodes.

       getntype() is a general function that is used to determine  the	number
       of  nodes  whose	 node  types  have certain bits set to certain values.
       This is a flexible tool which allows the user to obtain	very  specific
       information about the capabilities of nodes in the system.

   Type Inquiries
       You may need more detailed information on the number and types of nodes
       in the system than provided by the convenience functions.  You may, for
       example, want to know the number of computing nodes with attached video
       displays.  The getntype() function is used for this purpose.

       Node types are interpreted as bit fields, and each node type has a dif‐
       ferent  bit set.	 A bitmask having all bits set, NT_ALL, is also avail‐
       able.  Note that NT_ALL does not include	 NT_JONES  nor	NT_BOOT	 since
       these node characteristics are not inherent to the nodes, but depend on
       the node from which the query is made.  The node types are thus:

       Nodetype	    Value     Bitmask

       NT_ITB	    1	      ...00000001
       NT_CAST	    2	      ...00000010
       NT_WASTE	    4	      ...00000100
       NT_DISK	    8	      ...00001000
       NT_TUBE	    16	      ...00010000
       NT_ALL	    31	      ...00011111
       NT_JONES	    32	      ...00100000
       NT_BOOT	    64	      ...01000000

       The typemask argument to getntype() is used to specify which  bits  are
       of  interest.   These are set to 1, all others are set to 0.  The node‐
       type argument is used to specify what values these  bits	 should	 take.
       getntype()  then	 compares the relevant bits (as specified by typemask)
       in the node type of each node in the system, to see if  they  have  the
       appropriate value (as specified by nodetype).

       To  learn the number of nodes that have video capabilities, the bits of
       interest are NT_WASTE and NT_TUBE, thus typemask is 20.	NT_WASTE  must
       be  0  and NT_TUBE must be 1, which combined gives nodetype as 16.  The
       complete call to getntype() is:

       nnodes = getntype(NT_TUBE, NT_TUBE | NT_WASTE);

       To learn the number of compute nodes that have an attached  video  dis‐
       play,  but  no  other capabilities, all bits must be considered and all
       bits except NT_TUBE must be clear (0).  The complete function call is:

       nnodes = getntype(NT_TUBE, NT_ALL);

C RETURN VALUE
       getnodeid() and getorigin() both return	node  identifiers.   NOTNODEID
       (defined in <net.h>) is returned if an error occurred.  Likewise, getn‐
       odetype() returns a valid node type or NOTNODETYPE in the case  of  er‐
       ror.   The  return  values upon successful completion for the remaining
       functions are described above; they return -1 if an error  occurs.   In
       all  cases of error, the global error variable errno is set to indicate
       the error.

FORTRAN RETURN VALUE
       IGNDID() and IGORGN() both return  node	identifiers.   NOTNODEID  (see
       CONSTANTS(5)) is returned if an error occurred.	Likewise, IGNDTP() re‐
       turns a valid node type or NOTNODETYPE in the case of error.   The  re‐
       turn  values upon successful completion for the remaining functions are
       described above; they return -1 if an error occurs.

SEE ALSO
       getroute(2), CONSTANTS(5)

LAM 7.1.2			  March, 2006			   GETNTYPE(2)
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