SCALAPACK 2.2.2
LAPACK: Linear Algebra PACKage
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◆ pslamr1d()

subroutine pslamr1d ( integer  n,
real, dimension( * )  a,
integer  ia,
integer  ja,
integer, dimension( * )  desca,
real, dimension( * )  b,
integer  ib,
integer  jb,
integer, dimension( * )  descb 
)

Definition at line 1 of file pslamr1d.f.

2*
3* -- ScaLAPACK routine (version 1.7) --
4* University of Tennessee, Knoxville, Oak Ridge National Laboratory,
5* and University of California, Berkeley.
6* October 15, 1999
7*
8* .. Scalar Arguments ..
9 INTEGER IA, IB, JA, JB, N
10* ..
11* .. Array Arguments ..
12 INTEGER DESCA( * ), DESCB( * )
13 REAL A( * ), B( * )
14* ..
15*
16* Bugs
17* ====
18*
19* I am not sure that this works correctly when IB and JB are not equal
20* to 1. Indeed, I suspect that IB should always be set to 1 or ignored
21* with 1 used in its place.
22*
23* PSLAMR1D has not been tested except withint the contect of
24* PSSYPTRD, the prototype reduction to tridiagonal form code.
25*
26* Purpose
27*
28* =======
29*
30* PSLAMR1D redistributes a one-dimensional row vector from one data
31* decomposition to another.
32*
33* This is an auxiliary routine called by PSSYTRD to redistribute D, E
34* and TAU.
35*
36* Notes
37* =====
38*
39* Although all processes call PSGEMR2D, only the processes that own
40* the first column of A send data and only processes that own the
41* first column of B receive data. The calls to SGEBS2D/SGEBR2D
42* spread the data down.
43*
44* Arguments
45* =========
46*
47* N (global input) INTEGER
48* The size of the matrix to be transposed.
49*
50* A (local output) COMPLEX*16 pointer into the
51* local memory to an array of dimension (LOCc(JA+N-1)).
52* On output, A is replicated across all processes in
53* this processor column.
54*
55* IA (global input) INTEGER
56* A's global row index, which points to the beginning of
57* the submatrix which is to be operated on.
58*
59* JA (global input) INTEGER
60* A's global column index, which points to the beginning of
61* the submatrix which is to be operated on.
62*
63* DESCA (global and local input) INTEGER array of dimension DLEN_.
64* The array descriptor for the distributed matrix A.
65*
66* B (local input/local output) COMPLEX*16 pointer into the
67* local memory to an array of dimension (LOCc(JB+N-1)).
68*
69* IB (global input) INTEGER
70* B's global row index, NOT USED
71*
72* JB (global input) INTEGER
73* B's global column index, which points to the beginning of
74* the submatrix which is to be operated on.
75*
76* DESCB (global and local input) INTEGER array of dimension DLEN_.
77* The array descriptor for the distributed matrix B.
78*
79* WORK (local workspace) COMPLEX*16 array, dimension ( LWORK )
80*
81* LWORK (local input) INTEGER
82* The dimension of the array WORK.
83* LWORK is local input and must be at least
84* LWORK >= NB * NUMROC( N, 1, 0, 0, NPROW )
85*
86* =====================================================================
87*
88* .. Parameters ..
89 INTEGER BLOCK_CYCLIC_2D, DLEN_, DTYPE_, CTXT_, M_, N_,
90 $ MB_, NB_, RSRC_, CSRC_, LLD_
91 parameter( block_cyclic_2d = 1, dlen_ = 9, dtype_ = 1,
92 $ ctxt_ = 2, m_ = 3, n_ = 4, mb_ = 5, nb_ = 6,
93 $ rsrc_ = 7, csrc_ = 8, lld_ = 9 )
94* ..
95* .. Local Scalars ..
96 INTEGER I, ICTXT, MYCOL, MYROW, NPCOL, NPROW, NQ
97* ..
98* .. Local Arrays ..
99 INTEGER DESCAA( DLEN_ ), DESCBB( DLEN_ )
100* ..
101* .. External Subroutines ..
102 EXTERNAL blacs_gridinfo, psgemr2d, sgebr2d, sgebs2d
103* ..
104* .. External Functions ..
105 INTEGER NUMROC
106 EXTERNAL numroc
107* ..
108* .. Executable Statements ..
109* This is just to keep ftnchek and toolpack/1 happy
110 IF( block_cyclic_2d*csrc_*ctxt_*dlen_*dtype_*lld_*mb_*m_*nb_*n_*
111 $ rsrc_.LT.0 )RETURN
112*
113* Quick return if possible
114*
115 IF( n.LE.0 )
116 $ RETURN
117*
118 DO 10 i = 1, dlen_
119 descaa( i ) = desca( i )
120 descbb( i ) = descb( i )
121 10 CONTINUE
122*
123 descaa( m_ ) = 1
124 descbb( m_ ) = 1
125 descaa( lld_ ) = 1
126 descbb( lld_ ) = 1
127*
128 ictxt = descb( ctxt_ )
129 CALL psgemr2d( 1, n, a, ia, ja, descaa, b, ib, jb, descbb, ictxt )
130*
131 CALL blacs_gridinfo( ictxt, nprow, npcol, myrow, mycol )
132 nq = numroc( n, descb( nb_ ), mycol, 0, npcol )
133*
134 IF( myrow.EQ.0 ) THEN
135 CALL sgebs2d( ictxt, 'C', ' ', nq, 1, b, nq )
136 ELSE
137 CALL sgebr2d( ictxt, 'C', ' ', nq, 1, b, nq, 0, mycol )
138 END IF
139*
140 RETURN
141*
142* End of PSLAMR1D
143*
numroc
integer function numroc(n, nb, iproc, isrcproc, nprocs)
Definition numroc.f:2
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