TESTING/MATGEN/dlatm7.f(3)

NAME
TESTING/MATGEN/dlatm7.f

SYNOPSIS

  Functions/Subroutines
subroutine dlatm7 (mode, cond, irsign, idist, iseed, d, n, rank, info)
DLATM7

Function/Subroutine Documentation

  subroutine dlatm7 (integer mode, double precision cond, integer irsign, integer idist, integer, dimension( 4 ) iseed, double precision, dimension( * ) d, integer n, integer rank, integer info)

DLATM7

Purpose:

    !>
    !>    DLATM7 computes the entries of D as specified by MODE
    !>    COND and IRSIGN. IDIST and ISEED determine the generation
    !>    of random numbers. DLATM7 is called by DLATMT to generate
    !>    random test matrices.
    !>

    !>  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:RANK)=1.0/COND
    !>           MODE = 2 sets D(1:RANK-1)=1 and D(RANK)=1.0/COND
    !>           MODE = 3 sets D(I)=COND**(-(I-1)/(RANK-1)) I=1:RANK
    !>
    !>           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 1 or -1 with probability .5
    !>
    !>  IDIST  - CHARACTER*1
    !>           On entry, IDIST specifies the type of distribution to be
    !>           used to generate a random matrix .
    !>           1 => UNIFORM( 0, 1 )
    !>           2 => UNIFORM( -1, 1 )
    !>           3 => NORMAL( 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 DLATM7
    !>           to continue the same random number sequence.
    !>           Changed on exit.
    !>
    !>  D      - DOUBLE PRECISION 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.
    !>
    !>  RANK   - INTEGER
    !>           The rank of matrix to be generated for modes 1,2,3 only.
    !>           D( RANK+1:N ) = 0.
    !>           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 3
    !>           -7  => if N negative
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 120 of file dlatm7.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.