SUBROUTINE PSSVDCMP( M, N, JOBTYPE, S, SC, U, UC, IU, JU, DESCU, $ VT, VTC, IVT, JVT, DESCVT, THRESH, RESULT, $ DELTA, WORK, LWORK ) * * -- ScaLAPACK routine (version 1.7) -- * University of Tennessee, Knoxville, Oak Ridge National Laboratory, * and University of California, Berkeley. * May 1, 1997 * * .. Scalar Arguments .. INTEGER IU, IVT, JOBTYPE, JU, JVT, LWORK, M, N REAL DELTA, THRESH * .. * .. Array Arguments .. INTEGER DESCU( * ), DESCVT( * ), RESULT( * ) REAL S( * ), SC( * ), U( * ), UC( * ), VT( * ), $ VTC( * ), WORK( * ) * .. * * Purpose * ======== * Testing how accurately "full" and "partial" decomposition options * provided by PSGESVD correspond to each other. * * Notes * ===== * * Each global data object is described by an associated description * vector. This vector stores the information required to establish * the mapping between an object element and its corresponding process * and memory location. * * Let A be a generic term for any 2D block cyclicly distributed array. * Such a global array has an associated description vector DESCA. * In the following comments, the character _ should be read as * "of the global array". * * NOTATION STORED IN EXPLANATION * --------------- -------------- -------------------------------------- * DTYPE_A(global) DESCA( DTYPE_ )The descriptor type. In this case, * DTYPE_A = 1. * CTXT_A (global) DESCA( CTXT_ ) The BLACS context handle, indicating * the BLACS process grid A is distribu- * ted over. The context itself is glo- * bal, but the handle (the integer * value) may vary. * M_A (global) DESCA( M_ ) The number of rows in the global * array A. * N_A (global) DESCA( N_ ) The number of columns in the global * array A. * MB_A (global) DESCA( MB_ ) The blocking factor used to distribute * the rows of the array. * NB_A (global) DESCA( NB_ ) The blocking factor used to distribute * the columns of the array. * RSRC_A (global) DESCA( RSRC_ ) The process row over which the first * row of the array A is distributed. * CSRC_A (global) DESCA( CSRC_ ) The process column over which the * first column of the array A is * distributed. * LLD_A (local) DESCA( LLD_ ) The leading dimension of the local * array. LLD_A >= MAX(1,LOCr(M_A)). * * Let K be the number of rows or columns of a distributed matrix, * and assume that its process grid has dimension p x q. * LOCr( K ) denotes the number of elements of K that a process * would receive if K were distributed over the p processes of its * process column. * Similarly, LOCc( K ) denotes the number of elements of K that a * process would receive if K were distributed over the q processes of * its process row. * The values of LOCr() and LOCc() may be determined via a call to the * ScaLAPACK tool function, NUMROC: * LOCr( M ) = NUMROC( M, MB_A, MYROW, RSRC_A, NPROW ), * LOCc( N ) = NUMROC( N, NB_A, MYCOL, CSRC_A, NPCOL ). * An upper bound for these quantities may be computed by: * LOCr( M ) <= ceil( ceil(M/MB_A)/NPROW )*MB_A * LOCc( N ) <= ceil( ceil(N/NB_A)/NPCOL )*NB_A * * Arguments * ========== * * M (global input) INTEGER * Number of rows of the distributed matrix, for which * SVD was calculated * * N (global input) INTEGER * Number of columns of the distributed matrix, for which * SVD was calculated * * JOBTYPE (global input) INTEGER * Depending on the value of this parameter, * the following comparisons are performed: * * JOBTYPE | COMPARISON * ------------------------------------------- * 2 | | U - UC | / ( M ulp ) > THRESH, * 3 | | VT - VTC | / ( N ulp ) > THRESH * * In addition, for JOBTYPE = 2:4 comparison * | S1 - S2 | / ( SIZE ulp |S| ) > THRESH * is performed. Positive result of any of the comparisons * typically indicates erroneous computations and sets * to one corresponding element of array RESULT * * S (global input) REAL array of singular values * calculated for JOBTYPE equal to 1 * * SC (global input) REAL array of singular values * calculated for JOBTYPE nonequal to 1 * * U (local input) REAL array of left singular * vectors calculated for JOBTYPE equal to 1, local * dimension (MP, SIZEQ), global dimension (M, SIZE) * * UC (local input) REAL array of left singular * vectors calculated for JOBTYPE non equal to 1, local * dimension (MP, SIZEQ), global dimension (M, SIZE) * * IU (global input) INTEGER * The row index in the global array U indicating the first * row of sub( U ). * * JU (global input) INTEGER * The column index in the global array U indicating the * first column of sub( U ). * * DESCU (global input) INTEGER array of dimension DLEN_ * The array descriptor for the distributed matrix U and UC * * V (local input) REAL array of right singular * vectors calculated for JOBTYPE equal to 1, local * dimension (SIZEP, NQ), global dimension (SIZE, N) * * VC (local input) REAL array of right singular * vectors calculated for JOBTYPE non equal to 1, local * dimension (SIZEP, NQ), global dimension (SIZE, N) * * IVT (global input) INTEGER * The row index in the global array VT indicating the first * row of sub( VT ). * * JVT (global input) INTEGER * The column index in the global array VT indicating the * first column of sub( VT ). * * DESCVT (global input) INTEGER array of dimension DLEN_ * The array descriptor for the distributed matrix VT and * VTC * * THRESH (global input) REAL * The threshold value for the test ratios. A result is * included in the output file if RESULT >= THRESH. The test * ratios are scaled to be O(1), so THRESH should be a small * multiple of 1, e.g., 10 or 100. To have every test ratio * printed, use THRESH = 0. * * RESULT (global input/output) INTEGER array. * Every nonzero entry corresponds to erroneous computation. * * DELTA (global output) REAL * maximum of the available of the following three values * | U - UC | / ( M ulp THRESH ), * | VT - VT | / ( N ulp THRESH ), * | S1 - S2 | / ( SIZE ulp |S| THRESH ) * * WORK (local workspace/output) REAL array, * dimension (LWORK) * On exit, WORK(1) returns the optimal LWORK. * * LWORK (local input) INTEGER * The dimension of the array WORK. * * ====================================================================== * * .. Parameters .. INTEGER BLOCK_CYCLIC_2D, DLEN_, DTYPE_, CTXT_, M_, N_, $ MB_, NB_, RSRC_, CSRC_, LLD_ PARAMETER ( BLOCK_CYCLIC_2D = 1, DLEN_ = 9, DTYPE_ = 1, $ CTXT_ = 2, M_ = 3, N_ = 4, MB_ = 5, NB_ = 6, $ RSRC_ = 7, CSRC_ = 8, LLD_ = 9 ) * .. * .. Local Scalars .. INTEGER COLPTR, I, INFO, J, LWMIN, MYCOL, MYROW, NPCOL, $ NPROW, NQ, RESULTS, SIZE, SIZEPOS, SIZEQ REAL ACCUR, CMP, NORMDIFS, NORMDIFU, NORMDIFV, $ NORMS, ULP * .. * .. External Functions .. INTEGER NUMROC REAL SLANGE, PSLAMCH, PSLANGE EXTERNAL NUMROC, SLANGE, PSLAMCH, PSLANGE * .. * .. External Subroutines .. EXTERNAL BLACS_GRIDINFO, CHK1MAT, PXERBLA * .. * .. Intrinsic Functions .. INTRINSIC MAX, MIN * .. * .. Executable Statements .. * This is just to keep ftnchek happy IF( BLOCK_CYCLIC_2D*CSRC_*DLEN_*DTYPE_*MB_*M_*N_*RSRC_.LT.0 ) $ RETURN * RESULTS = 0 NORMDIFS = 0 NORMDIFU = 0 NORMDIFV = 0 SIZE = MIN( M, N ) * * Sizepos is a number of parameters to pdsvdcmp plus one. It's used * for the error reporting. * SIZEPOS = 17 INFO = 0 CALL BLACS_GRIDINFO( DESCU( CTXT_ ), NPROW, NPCOL, MYROW, MYCOL ) IF( NPROW.EQ.-1 ) THEN INFO = -607 ELSE CALL CHK1MAT( M, 1, SIZE, SIZEPOS, 1, 1, DESCU, 8, INFO ) CALL CHK1MAT( SIZE, SIZEPOS, N, 2, 1, 1, DESCVT, 11, INFO ) END IF * IF( INFO.EQ.0 ) THEN * * Calculate workspace. * SIZEQ = NUMROC( SIZE, DESCU( NB_ ), MYCOL, 0, NPCOL ) NQ = NUMROC( N, DESCVT( NB_ ), MYCOL, 0, NPCOL ) LWMIN = MAX( SIZEQ, NQ ) + 4 WORK( 1 ) = LWMIN IF( LWORK.EQ.-1 ) $ GO TO 60 IF( LWORK.LT.LWMIN ) THEN INFO = -16 ELSE IF( THRESH.LE.0 ) THEN INFO = -12 END IF END IF * IF( INFO.NE.0 ) THEN CALL PXERBLA( DESCU( CTXT_ ), 'PSSVDCMP', -INFO ) RETURN END IF * ULP = PSLAMCH( DESCU( CTXT_ ), 'P' ) * * Make comparison of singular values. * NORMS = SLANGE( '1', SIZE, 1, S, SIZE, WORK ) DO 10 I = 1, SIZE SC( I ) = S( I ) - SC( I ) 10 CONTINUE * NORMDIFS = SLANGE( '1', SIZE, 1, SC, SIZE, WORK ) ACCUR = ULP*SIZE*NORMS*THRESH * IF( NORMDIFS.GT.ACCUR ) $ RESULTS = 1 IF( NORMDIFS.EQ.0 .AND. ACCUR.EQ.0 ) THEN NORMDIFS = 0 ELSE NORMDIFS = NORMDIFS / ACCUR END IF * IF( JOBTYPE.EQ.2 ) THEN * RESULT( 5 ) = RESULTS ACCUR = ULP*M*THRESH DO 30 J = 1, SIZEQ COLPTR = DESCU( LLD_ )*( J-1 ) DO 20 I = 1, DESCU( LLD_ ) UC( I+COLPTR ) = U( I+COLPTR ) - UC( I+COLPTR ) 20 CONTINUE 30 CONTINUE * NORMDIFU = PSLANGE( '1', M, SIZE, UC, IU, JU, DESCU, WORK ) * IF( NORMDIFU.GE.ACCUR ) $ RESULT( 6 ) = 1 IF( NORMDIFU.EQ.0 .AND. ACCUR.EQ.0 ) THEN NORMDIFU = 0 ELSE NORMDIFU = NORMDIFU / ACCUR END IF * ELSE IF( JOBTYPE.EQ.3 ) THEN * RESULT( 7 ) = RESULTS ACCUR = ULP*N*THRESH DO 50 J = 1, NQ COLPTR = DESCVT( LLD_ )*( J-1 ) DO 40 I = 1, DESCVT( LLD_ ) VTC( I+COLPTR ) = VT( I+COLPTR ) - VTC( I+COLPTR ) 40 CONTINUE 50 CONTINUE * NORMDIFV = PSLANGE( '1', SIZE, N, VTC, IVT, JVT, DESCVT, WORK ) * IF( NORMDIFV.GE.ACCUR ) $ RESULT( 8 ) = 1 * IF( NORMDIFV.EQ.0 .AND. ACCUR.EQ.0 ) THEN NORMDIFV = 0 ELSE NORMDIFV = NORMDIFV / ACCUR END IF * ELSE IF( JOBTYPE.EQ.4 ) THEN * RESULT( 9 ) = RESULTS * END IF * CMP = MAX( NORMDIFV, NORMDIFU ) DELTA = MAX( CMP, NORMDIFS ) * 60 CONTINUE * * End of PSSVDCMP * RETURN END