TESTING/MATGEN/dlatm7.f(3)                            Library Functions Manual

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.

LAPACK                          Version 3.12.0      TESTING/MATGEN/dlatm7.f(3)