id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
392	ifort14 anomalies	Ian Culverwell	Ian Culverwell	"ROPP8.0 beta reviewer Dave Offiler (UKMO) says

{{{
- ROPP_1DVAR: test t_1dvar_GRAS_05_bangle fails (ifort):

    Testing 1D-Var using GRAS bending angles with colocated ECMWF backgrounds
 
    Running t_1dvar_GRAS_05_bangle (1DVAR GRAS; default) ...
 
    ERROR (from ropp_io_fields_compare):  prof1%Lev1b%bangle_sigma differs from 
    prof2%Lev1b%bangle_sigma (max|diff| =  0.12532E-05 >  0.10000E-05)
 
    ERROR (from ropp_io_fields_compare):  prof1%Lev1b%bangle differs from 
    prof2%Lev1b%bangle (max|diff| =  0.75710E-05 >  0.10000E-05)
    INFO (from ropp_1dvar_compare):     2 elements of IT-1DVAR-05_bangle.1.nc 
    and ../data/IT-1DVAR-05_bangle.1_reference.nc differ significantly
    ****************************
    ********** *FAIL* **********
    ****************************
    ... examine t_1dvar_GRAS_05_bangle.log for details
       
  The first case looks a marginal excess difference, but the second is more 
  significant at 7x the threshold. The log shows only INFO messages; it would 
  be helpful if the profile number having the max. diff were output. 
  [severity: medium/high?]

  
- ROPP_1DVAR: test t_1dvar_GRAS_05_bangle fails (ifort):

    Running t_1dvar_GRAS_05newop_refrac (1DVAR GRAS; new interp) ...
 
    ERROR (from ropp_io_fields_compare):  prof1%Lev2a%refrac_sigma differs 
    from prof2%Lev2a%refrac_sigma (max|diff| =  0.12619E-01 >  0.10000E-02)
 
    ERROR (from ropp_io_fields_compare):  prof1%Lev2b%press differs from 
    prof2%Lev2b%press (max|diff| =  0.12473E+00 >  0.10000E+00)
 
    ERROR (from ropp_io_fields_compare):  prof1%Lev2b%geop differs from 
    prof2%Lev2b%geop (max|diff| =  0.10156E+01 >  0.10000E+01)
    INFO (from ropp_1dvar_compare):     3 elements of IT-1DVAR-05newop_refrac.1.nc and 
    ../data/IT-1DVAR-05newop_refrac.1_reference.nc differ significantly
    ****************************
    ********** *FAIL* **********
    ****************************
    ... examine t_1dvar_GRAS_05newop_refrac.log for details

   All cases (and especially the last) appear to be only marginally exceeding 
   the threshold. The log shows only INFO messages; it would be helpful if the
   profile number having the max. diff were output.
  [severity: medium/high?]
  
  
- ROPP_1DVAR: gfortran, g95 & sunf95 tests *all* PASS. so some compiler-
  dependency here. Diff'ing the gfortran, g95 & sunf95 logs shows them to be
  identical (apart from just one value, 0.0001 different). But while the ifort
  log has many differences, all are rather small and almost all in the last  1-2
  decimal places - no significant deviations such as additional  iterations, for
  instance, except that one profile in the second case has one  more iteration
  with ifort. But it's still to be noted that ifort is the odd compiler out of
  the four tested, and this needs futher investigation to tell whether the
  differences are significant in practice for the 1D-Var  output or not.
}}}

This is either an ifort14 bug, or a deep-rooted numerical deep rooted numerical ill-conditioning (like #301 and #349) which has only come to light with this compiler --- which would not be a ten minute job to fix. 

Fixing the log file to show which profile was causing the trouble would be relatively easy, however."	defect	closed	normal	9.0	ropp_1dvar	7.1	fixed	ifort14