dbteps()

double precision function dbteps

Definition at line 13135 of file blacstest.f.

*
*     .. External Functions ..
      INTEGER IBTMYPROC, IBTNPROCS, IBTMSGID
      DOUBLE PRECISION DLAMCH
      EXTERNAL ibtmyproc, ibtnprocs, ibtmsgid, dlamch
*     ..
*     .. Local Scalars ..
      INTEGER I, IAM, NNODES
      DOUBLE PRECISION EPS, EPS2
      SAVE eps
      DATA eps /-22.0d0/
*     ..
*     .. Executable Statements ..
*
*     First time called, must get max epsilon possessed by any
*     participating process
*
      IF( eps .EQ. -22.0d0 ) THEN
         iam = ibtmyproc()
         nnodes = ibtnprocs()
         eps = dlamch('epsilon')
         IF( iam .EQ. 0 ) THEN
            IF( nnodes .GT. 1 ) THEN
               DO 10 i = 1, nnodes-1
                  CALL btrecv( 6, 1, eps2, i, ibtmsgid()+20 )
                  IF( eps .LT. eps2 ) eps = eps2
   10          CONTINUE
            END IF
            CALL btsend( 6, 1, eps, -1, ibtmsgid()+20 )
         ELSE
            CALL btsend( 6, 1, eps, 0, ibtmsgid()+20 )
            CALL btrecv( 6, 1, eps, 0, ibtmsgid()+20 )
         ENDIF
      END IF
      dbteps = eps
      RETURN
*
*     End DBTEPS
*

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