Contents

• NAME
• SYNOPSIS
• PURPOSE
• ARGUMENTS

NAME

     sgthrz - Gather and zero.

SYNOPSIS

      SUBROUTINE SGTHRZ(NZ, Y, X, INDX)

      REAL Y(*), X(*)
      INTEGER NZ
      INTEGER INDX(*)

      SUBROUTINE SGTHRZ_64(NZ, Y, X, INDX)

      REAL Y(*), X(*)
      INTEGER*8 NZ
      INTEGER*8 INDX(*)

     F95 INTERFACE
      SUBROUTINE GTHRZ([NZ], Y, X, INDX)

      REAL, DIMENSION(:) :: Y, X
      INTEGER :: NZ
      INTEGER, DIMENSION(:) :: INDX

      SUBROUTINE GTHRZ_64([NZ], Y, X, INDX)

      REAL, DIMENSION(:) :: Y, X
      INTEGER(8) :: NZ
      INTEGER(8), DIMENSION(:) :: INDX

PURPOSE

     SGTHRZ - Gathers the specified elements from a vector y in
     full storage form into a vector x in compressed form.  The
     gathered elements of y are set to zero.  Only the elements
     of y whose indices are listed in indx are referenced.

      do i = 1, n
        x(i) = y(indx(i))
        y(indx(i)) = 0
      enddo

ARGUMENTS

     NZ (input) - INTEGER
             Number of elements in the compressed form.
             Unchanged on exit.

     Y (input/output)
             Vector in full storage form.  Gathered elements are
             set to zero.
     X (output)
             Vector in compressed form.  Contains elements of y
             whose indices are listed in indx on exit.

     INDX (input) - INTEGER
             Vector containing the indices of the compressed
             form.  It is assumed that the elements in INDX are
             distinct and greater than zero.  Unchanged on exit.