SUBROUTINE ZLATM1( MODE, COND, IRSIGN, IDIST, ISEED, D, N, INFO ) * * -- LAPACK auxiliary test routine (version 3.1) -- * Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. * November 2006 * * .. Scalar Arguments .. INTEGER IDIST, INFO, IRSIGN, MODE, N DOUBLE PRECISION COND * .. * .. Array Arguments .. INTEGER ISEED( 4 ) COMPLEX*16 D( * ) * .. * * Purpose * ======= * * ZLATM1 computes the entries of D(1..N) as specified by * MODE, COND and IRSIGN. IDIST and ISEED determine the generation * of random numbers. ZLATM1 is called by CLATMR to generate * random test matrices for LAPACK programs. * * Arguments * ========= * * MODE - INTEGER * On entry describes how D is to be computed: * MODE = 0 means do not change D. * MODE = 1 sets D(1)=1 and D(2:N)=1.0/COND * MODE = 2 sets D(1:N-1)=1 and D(N)=1.0/COND * MODE = 3 sets D(I)=COND**(-(I-1)/(N-1)) * MODE = 4 sets D(i)=1 - (i-1)/(N-1)*(1 - 1/COND) * MODE = 5 sets D to random numbers in the range * ( 1/COND , 1 ) such that their logarithms * are uniformly distributed. * MODE = 6 set D to random numbers from same distribution * as the rest of the matrix. * MODE < 0 has the same meaning as ABS(MODE), except that * the order of the elements of D is reversed. * Thus if MODE is positive, D has entries ranging from * 1 to 1/COND, if negative, from 1/COND to 1, * Not modified. * * COND - DOUBLE PRECISION * On entry, used as described under MODE above. * If used, it must be >= 1. Not modified. * * IRSIGN - INTEGER * On entry, if MODE neither -6, 0 nor 6, determines sign of * entries of D * 0 => leave entries of D unchanged * 1 => multiply each entry of D by random complex number * uniformly distributed with absolute value 1 * * IDIST - CHARACTER*1 * On entry, IDIST specifies the type of distribution to be * used to generate a random matrix . * 1 => real and imaginary parts each UNIFORM( 0, 1 ) * 2 => real and imaginary parts each UNIFORM( -1, 1 ) * 3 => real and imaginary parts each NORMAL( 0, 1 ) * 4 => complex number uniform in DISK( 0, 1 ) * Not modified. * * ISEED - INTEGER array, dimension ( 4 ) * On entry ISEED specifies the seed of the random number * generator. The random number generator uses a * linear congruential sequence limited to small * integers, and so should produce machine independent * random numbers. The values of ISEED are changed on * exit, and can be used in the next call to ZLATM1 * to continue the same random number sequence. * Changed on exit. * * D - COMPLEX*16 array, dimension ( MIN( M , N ) ) * Array to be computed according to MODE, COND and IRSIGN. * May be changed on exit if MODE is nonzero. * * N - INTEGER * Number of entries of D. Not modified. * * INFO - INTEGER * 0 => normal termination * -1 => if MODE not in range -6 to 6 * -2 => if MODE neither -6, 0 nor 6, and * IRSIGN neither 0 nor 1 * -3 => if MODE neither -6, 0 nor 6 and COND less than 1 * -4 => if MODE equals 6 or -6 and IDIST not in range 1 to 4 * -7 => if N negative * * ===================================================================== * * .. Parameters .. DOUBLE PRECISION ONE PARAMETER ( ONE = 1.0D0 ) * .. * .. Local Scalars .. INTEGER I DOUBLE PRECISION ALPHA, TEMP COMPLEX*16 CTEMP * .. * .. External Functions .. DOUBLE PRECISION DLARAN COMPLEX*16 ZLARND EXTERNAL DLARAN, ZLARND * .. * .. External Subroutines .. EXTERNAL XERBLA, ZLARNV * .. * .. Intrinsic Functions .. INTRINSIC ABS, DBLE, EXP, LOG * .. * .. Executable Statements .. * * Decode and Test the input parameters. Initialize flags & seed. * INFO = 0 * * Quick return if possible * IF( N.EQ.0 ) $ RETURN * * Set INFO if an error * IF( MODE.LT.-6 .OR. MODE.GT.6 ) THEN INFO = -1 ELSE IF( ( MODE.NE.-6 .AND. MODE.NE.0 .AND. MODE.NE.6 ) .AND. $ ( IRSIGN.NE.0 .AND. IRSIGN.NE.1 ) ) THEN INFO = -2 ELSE IF( ( MODE.NE.-6 .AND. MODE.NE.0 .AND. MODE.NE.6 ) .AND. $ COND.LT.ONE ) THEN INFO = -3 ELSE IF( ( MODE.EQ.6 .OR. MODE.EQ.-6 ) .AND. $ ( IDIST.LT.1 .OR. IDIST.GT.4 ) ) THEN INFO = -4 ELSE IF( N.LT.0 ) THEN INFO = -7 END IF * IF( INFO.NE.0 ) THEN CALL XERBLA( 'ZLATM1', -INFO ) RETURN END IF * * Compute D according to COND and MODE * IF( MODE.NE.0 ) THEN GO TO ( 10, 30, 50, 70, 90, 110 )ABS( MODE ) * * One large D value: * 10 CONTINUE DO 20 I = 1, N D( I ) = ONE / COND 20 CONTINUE D( 1 ) = ONE GO TO 120 * * One small D value: * 30 CONTINUE DO 40 I = 1, N D( I ) = ONE 40 CONTINUE D( N ) = ONE / COND GO TO 120 * * Exponentially distributed D values: * 50 CONTINUE D( 1 ) = ONE IF( N.GT.1 ) THEN ALPHA = COND**( -ONE / DBLE( N-1 ) ) DO 60 I = 2, N D( I ) = ALPHA**( I-1 ) 60 CONTINUE END IF GO TO 120 * * Arithmetically distributed D values: * 70 CONTINUE D( 1 ) = ONE IF( N.GT.1 ) THEN TEMP = ONE / COND ALPHA = ( ONE-TEMP ) / DBLE( N-1 ) DO 80 I = 2, N D( I ) = DBLE( N-I )*ALPHA + TEMP 80 CONTINUE END IF GO TO 120 * * Randomly distributed D values on ( 1/COND , 1): * 90 CONTINUE ALPHA = LOG( ONE / COND ) DO 100 I = 1, N D( I ) = EXP( ALPHA*DLARAN( ISEED ) ) 100 CONTINUE GO TO 120 * * Randomly distributed D values from IDIST * 110 CONTINUE CALL ZLARNV( IDIST, ISEED, N, D ) * 120 CONTINUE * * If MODE neither -6 nor 0 nor 6, and IRSIGN = 1, assign * random signs to D * IF( ( MODE.NE.-6 .AND. MODE.NE.0 .AND. MODE.NE.6 ) .AND. $ IRSIGN.EQ.1 ) THEN DO 130 I = 1, N CTEMP = ZLARND( 3, ISEED ) D( I ) = D( I )*( CTEMP / ABS( CTEMP ) ) 130 CONTINUE END IF * * Reverse if MODE < 0 * IF( MODE.LT.0 ) THEN DO 140 I = 1, N / 2 CTEMP = D( I ) D( I ) = D( N+1-I ) D( N+1-I ) = CTEMP 140 CONTINUE END IF * END IF * RETURN * * End of ZLATM1 * END