dlaset.f.html
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SUBROUTINE <a name="DLASET.1"></a><a href="dlaset.f.html#DLASET.1">DLASET</a>( UPLO, M, N, ALPHA, BETA, A, LDA )
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> -- LAPACK auxiliary routine (version 3.1) --
</span><span class="comment">*</span><span class="comment"> Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
</span><span class="comment">*</span><span class="comment"> November 2006
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> .. Scalar Arguments ..
</span> CHARACTER UPLO
INTEGER LDA, M, N
DOUBLE PRECISION ALPHA, BETA
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment"> .. Array Arguments ..
</span> DOUBLE PRECISION A( LDA, * )
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> Purpose
</span><span class="comment">*</span><span class="comment"> =======
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> <a name="DLASET.19"></a><a href="dlaset.f.html#DLASET.1">DLASET</a> initializes an m-by-n matrix A to BETA on the diagonal and
</span><span class="comment">*</span><span class="comment"> ALPHA on the offdiagonals.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> Arguments
</span><span class="comment">*</span><span class="comment"> =========
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> UPLO (input) CHARACTER*1
</span><span class="comment">*</span><span class="comment"> Specifies the part of the matrix A to be set.
</span><span class="comment">*</span><span class="comment"> = 'U': Upper triangular part is set; the strictly lower
</span><span class="comment">*</span><span class="comment"> triangular part of A is not changed.
</span><span class="comment">*</span><span class="comment"> = 'L': Lower triangular part is set; the strictly upper
</span><span class="comment">*</span><span class="comment"> triangular part of A is not changed.
</span><span class="comment">*</span><span class="comment"> Otherwise: All of the matrix A is set.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> M (input) INTEGER
</span><span class="comment">*</span><span class="comment"> The number of rows of the matrix A. M >= 0.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> N (input) INTEGER
</span><span class="comment">*</span><span class="comment"> The number of columns of the matrix A. N >= 0.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> ALPHA (input) DOUBLE PRECISION
</span><span class="comment">*</span><span class="comment"> The constant to which the offdiagonal elements are to be set.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> BETA (input) DOUBLE PRECISION
</span><span class="comment">*</span><span class="comment"> The constant to which the diagonal elements are to be set.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> A (input/output) DOUBLE PRECISION array, dimension (LDA,N)
</span><span class="comment">*</span><span class="comment"> On exit, the leading m-by-n submatrix of A is set as follows:
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> if UPLO = 'U', A(i,j) = ALPHA, 1<=i<=j-1, 1<=j<=n,
</span><span class="comment">*</span><span class="comment"> if UPLO = 'L', A(i,j) = ALPHA, j+1<=i<=m, 1<=j<=n,
</span><span class="comment">*</span><span class="comment"> otherwise, A(i,j) = ALPHA, 1<=i<=m, 1<=j<=n, i.ne.j,
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> and, for all UPLO, A(i,i) = BETA, 1<=i<=min(m,n).
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> LDA (input) INTEGER
</span><span class="comment">*</span><span class="comment"> The leading dimension of the array A. LDA >= max(1,M).
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> =====================================================================
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> .. Local Scalars ..
</span> INTEGER I, J
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment"> .. External Functions ..
</span> LOGICAL <a name="LSAME.63"></a><a href="lsame.f.html#LSAME.1">LSAME</a>
EXTERNAL <a name="LSAME.64"></a><a href="lsame.f.html#LSAME.1">LSAME</a>
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment"> .. Intrinsic Functions ..
</span> INTRINSIC MIN
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment"> .. Executable Statements ..
</span><span class="comment">*</span><span class="comment">
</span> IF( <a name="LSAME.71"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( UPLO, <span class="string">'U'</span> ) ) THEN
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> Set the strictly upper triangular or trapezoidal part of the
</span><span class="comment">*</span><span class="comment"> array to ALPHA.
</span><span class="comment">*</span><span class="comment">
</span> DO 20 J = 2, N
DO 10 I = 1, MIN( J-1, M )
A( I, J ) = ALPHA
10 CONTINUE
20 CONTINUE
<span class="comment">*</span><span class="comment">
</span> ELSE IF( <a name="LSAME.82"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( UPLO, <span class="string">'L'</span> ) ) THEN
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> Set the strictly lower triangular or trapezoidal part of the
</span><span class="comment">*</span><span class="comment"> array to ALPHA.
</span><span class="comment">*</span><span class="comment">
</span> DO 40 J = 1, MIN( M, N )
DO 30 I = J + 1, M
A( I, J ) = ALPHA
30 CONTINUE
40 CONTINUE
<span class="comment">*</span><span class="comment">
</span> ELSE
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> Set the leading m-by-n submatrix to ALPHA.
</span><span class="comment">*</span><span class="comment">
</span> DO 60 J = 1, N
DO 50 I = 1, M
A( I, J ) = ALPHA
50 CONTINUE
60 CONTINUE
END IF
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> Set the first min(M,N) diagonal elements to BETA.
</span><span class="comment">*</span><span class="comment">
</span> DO 70 I = 1, MIN( M, N )
A( I, I ) = BETA
70 CONTINUE
<span class="comment">*</span><span class="comment">
</span> RETURN
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> End of <a name="DLASET.112"></a><a href="dlaset.f.html#DLASET.1">DLASET</a>
</span><span class="comment">*</span><span class="comment">
</span> END
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