SUBROUTINE PSFILLPAD( ICTXT, M, N, A, LDA, IPRE, IPOST, CHKVAL )
*
* -- ScaLAPACK tools routine (version 1.7) --
* University of Tennessee, Knoxville, Oak Ridge National Laboratory,
* and University of California, Berkeley.
* May 1, 1997
*
* .. Scalar Arguments ..
INTEGER ICTXT, IPOST, IPRE, LDA, M, N
REAL CHKVAL
* ..
* .. Array Arguments ..
REAL A( * )
* ..
*
* Purpose
* =======
*
* PSFILLPAD surrounds a two dimensional local array with a guard-
* zone initialized to the value CHKVAL. The user may later call the
* routine PSCHEKPAD to discover if the guardzone has been
* violated. There are three guardzones. The first is a buffer of size
* IPRE that is before the start of the array. The second is the buffer
* of size IPOST which is after the end of the array to be padded.
* Finally, there is a guard zone inside every column of the array to
* be padded, in the elements of A(M+1:LDA, J).
*
* Arguments
* =========
*
* ICTXT (global input) INTEGER
* The BLACS context handle, indicating the global context of
* the operation. The context itself is global.
*
* M (local input) INTEGER
* The number of rows in the local array.
*
* N (local input) INTEGER
* The number of columns in the local array.
*
* A (local input/local output) REAL, array of
* dimension (LDA,N). A location IPRE elements in front of
* the matrix to be padded.
*
* LDA (local input) INTEGER
* The leading Dimension of the local array to be padded.
*
* IPRE (local input) INTEGER
* The size of the guard zone to put before the start of
* padded array.
*
* IPOST (local input) INTEGER
* The size of the guard zone to put after padded array.
*
* CHKVAL (local input) REAL
* The value to pad matrix with.
*
* =====================================================================
*
* .. Local Scalars ..
INTEGER I, J, K
* ..
* .. Executable Statements ..
*
* Put check buffer in front of A
*
IF( IPRE.GT.0 ) THEN
DO 10 I = 1, IPRE
A( I ) = CHKVAL
10 CONTINUE
ELSE
WRITE( *, FMT = * ) 'WARNING no pre-guardzone in PSFILLPAD'
END IF
*
* Put check buffer in back of A
*
IF( IPOST.GT.0 ) THEN
J = IPRE+LDA*N+1
DO 20 I = J, J+IPOST-1
A( I ) = CHKVAL
20 CONTINUE
ELSE
WRITE( *, FMT = * ) 'WARNING no post-guardzone in PSFILLPAD'
END IF
*
* Put check buffer in all (LDA-M) gaps
*
IF( LDA.GT.M ) THEN
K = IPRE + M + 1
DO 40 J = 1, N
DO 30 I = K, K + (LDA-M) - 1
A( I ) = CHKVAL
30 CONTINUE
K = K + LDA
40 CONTINUE
END IF
*
RETURN
*
* End of PSFILLPAD
*
END