[Dart-dev] [6927] DART/trunk/random_seq/test_diff.f90: fixed up to return correct values.

[nancy at ucar.edu]

Revision: 6927
Author:   nancy
Date:     2014-04-25 08:19:30 -0600 (Fri, 25 Apr 2014)
Log Message:
-----------
fixed up to return correct values.

Modified Paths:
--------------
    DART/trunk/random_seq/test_diff.f90

-------------- next part --------------
Modified: DART/trunk/random_seq/test_diff.f90
===================================================================
--- DART/trunk/random_seq/test_diff.f90	2014-04-24 16:45:41 UTC (rev 6926)
+++ DART/trunk/random_seq/test_diff.f90	2014-04-25 14:19:30 UTC (rev 6927)
@@ -3,6 +3,15 @@
 ! http://www.image.ucar.edu/DAReS/DART/DART_download
 !
 ! $Id$
+!
+! FIXME:  the origins of this test program are lost to time.
+! i can see that it is trying to verify that the gaussian distribution
+! generator is working as expected, and it's also testing out the
+! computation at various (well, 2) precisions.  but i do not
+! believe that the computed and expected values are being computed
+! right.  the original code was computing the sqrt(distance**2) but
+! these are 1d values, not 2d, so the distance is simply abs(r1-r2)
+! without squares.  
 
 program test_diff
 
@@ -24,24 +33,16 @@
 integer :: i, iunit, io
 type (random_seq_type) :: r
 
-double precision ::  dpr1,  dpr2,  dpdist,  dpmean_dist
-real(digits12)   :: d12r1, d12r2, d12dist, d12mean_dist
-real(r8)         ::  r8r1,  r8r2,  r8dist,  r8mean_dist
-real(r4)         ::  r4r1,  r4r2,  r4dist,  r4mean_dist
+real(r8) :: r1, r2, dist2, mean_dist2
 
 !-----------------------------------------------------------------------------
 ! Namelist with default values
 
-double precision :: mean = 0.0d0, sd1 = 1.0d0, sd2 = 2.0d0
+real(r8) :: mean = 0.0, sd1 = 1.0, sd2 = 2.0, predicted
 integer :: iseed = 123
 
 namelist /test_diff_nml/ mean, sd1, sd2, iseed
 
-write(*, *) 'double precision       is ', kind(dpr1)
-write(*, *) 'digits12 is defined to be ', digits12
-write(*, *) 'r8       is defined to be ', r8
-write(*, *) 'r4       is defined to be ', r4
-
 call initialize_utilities('test_diff')
 call register_module(source,revision,revdate)
 
@@ -50,78 +51,25 @@
 read(iunit, nml = test_diff_nml, iostat = io)
 call check_namelist_read(iunit, io, "test_diff_nml")
 
-
-call init_random_seq(r,iseed)
-!-----------------------------------------------------------------------------
-write(*, *) 'double precision test:'
-!-----------------------------------------------------------------------------
-
-dpmean_dist = 0.0d0
-do i = 1, n
-   dpr1        = random_gaussian(r, 0.0d0, sd1)
-   dpr2        = random_gaussian(r,  mean, sd2)
-   dpdist      = dabs(dpr1 - dpr2)**2
-   dpmean_dist = dpmean_dist + dpdist
-end do
-
-write(*, *) 'sample mean distance  ', dpmean_dist / n
-write(*, *) 'predicted distance    ', sqrt(mean**2 + sd1**2 + sd2**2)
+write(*, *) 'sample size = ', n
+write(*, *) 'mean 1, 2 = ', 0.0, mean
+write(*, *) 'stddev 1, 2  = ', sd1, sd2
+write(*, *) 'predicted distance = ', sqrt(mean**2 + sd1**2 + sd2**2)
 write(*, *) ''
 
 
-!-----------------------------------------------------------------------------
-write(*, *) 'digits12 test:'
-!-----------------------------------------------------------------------------
-
 call init_random_seq(r,iseed)
-d12mean_dist = 0.0_digits12
+mean_dist2 = 0.0d0
 do i = 1, n
-   d12r1        = random_gaussian(r, 0.0d0, sd1)
-   d12r2        = random_gaussian(r,  mean, sd2)
-   d12dist      = abs(d12r1 - d12r2)**2
-   d12mean_dist = d12mean_dist + d12dist
+   r1 = random_gaussian(r, 0.0d0, sd1)
+   r2 = random_gaussian(r,  mean, sd2)
+   dist2 = (r1 - r2)**2
+   mean_dist2 = mean_dist2 + dist2
 end do
 
-write(*, *) 'sample mean distance  ', d12mean_dist / n
-write(*, *) 'predicted distance    ', sqrt(mean**2 + sd1**2 + sd2**2)
+write(*, *) 'sample mean distance = ', sqrt(mean_dist2 / n)
 write(*, *) ''
 
-!-----------------------------------------------------------------------------
-write(*, *) 'r8 test:'
-!-----------------------------------------------------------------------------
-
-call init_random_seq(r,iseed)
-r8mean_dist = 0.0_r8
-do i = 1, n
-   r8r1        = random_gaussian(r, 0.0d0, sd1)
-   r8r2        = random_gaussian(r,  mean, sd2)
-   r8dist      = abs(r8r1 - r8r2)**2
-   r8mean_dist = r8mean_dist + r8dist
-end do
-
-write(*, *) 'sample mean distance  ', r8mean_dist / n
-write(*, *) 'predicted distance    ', sqrt(mean**2 + sd1**2 + sd2**2)
-write(*, *) ''
-
-!-----------------------------------------------------------------------------
-write(*, *) 'r4 test:'
-!-----------------------------------------------------------------------------
-
-call init_random_seq(r,iseed)
-r4mean_dist = 0.0_r4
-do i = 1, n
-   r4r1        = random_gaussian(r, 0.0d0, sd1)
-   r4r2        = random_gaussian(r,  mean, sd2)
-   r4dist      = abs(r4r1 - r4r2)**2
-   r4mean_dist = r4mean_dist + r4dist
-end do
-
-write(*, *) 'sample mean distance  ', r4mean_dist / n
-write(*, *) 'predicted distance    ', sqrt(mean**2 + sd1**2 + sd2**2)
-write(*, *) ''
-
-call error_handler(E_MSG, 'test_diff', 'Finished successfully.',&
-                   source,revision,revdate)
 call finalize_utilities()