[Pw_forum] Issues running PWscf with long path names

[Layla Martin-Samos]

Dear Wiriwan, thank you for your notification and suggestions. I have
changed the dim of lines to 512. with -input the input file was already not
dumped (in the svn version).

best regards

Layla

2012/2/15 Wirawan Purwanto <wxpurw at wm.edu>

> (This is a re-send; I thought I already joined this forum before sending.)
>
> Hi,
>
> I found a trouble while running PWscf with long path names (e.g. wfcdir,
> or outdir), which I will explain below. I suffered the problem when running
> PWscf compiled with Intel Fortran (11 or 12, does not matter). I thought
> first that the problem was in the Intel Fortran itself, but it is not. Cf
> here:
>
> http://software.intel.com/en-us/forums/showthread.php?t=103025
>
> The root cause was the logic used in copying the input content in
> subroutine open_input_file_x() (file: Modules/open_close_input_file.f90).
> In official version 4.3.2 this correspond to lines 104-107 (some more lines
> printed below for context--it's the do while ...enddo block):
>
>        !
>        ! copy file
>        !
>        IF ( ierr == 0 ) THEN
>          lfound=.true.
>          dummy=""
>          do while (TRIM(dummy).ne."MAGICALME")         ! LINE 104
>            read(unit_loc,fmt='(A256)',END=10) dummy    ! LINE 105
>            write(stdtmp,*) trim(dummy)                 ! LINE 106
>          enddo                                         ! LINE 107
>
>
>
> Two problems I noted here:
>
> 1) the write statement with no formatting is troublesome: it adds a white
> space  at the beginning of each line. This manifests in the following
> symptom. One of my &CONTROL fields contain this line:
>
> outdir =
> '/mnt/lustre/wirawan0/BIGFILES.runtime/.qe-HACK-MnO/AFM2/rh.1x1x1/qe/Opium-GFRG/vol12.98'
> ,
>
> and PWscf, running this input, complains not being able to create subdir:
>
> '/mnt/lustre/wirawan0/BIGFILES.runtime/.qe-HACK-MnO/AFM2/rh.1x1x1/qe/O
> pium-GFRG/vol12.98'
>
> (notice stray whitespace between "O" and "pium"). Why is this? Because
> Intel Fortran library prepends a whitespace at each line of temporary input
> file (input_tmp.in), and happily truncates the output line to 80
> characters per line. Doing so, it continues the output in the next line
> (with an extra whitespace prepended *again*).
>
> Long story short, what you should have used for line 106 in the code above
> is:
>
>            write(stdtmp,'(A)') trim(dummy)
>
> It would not prepend any whitespace, and it would not truncate the output
> line every 80 characters.
>
>
> 2) In PWscf, path strings (such as outdir above) have a maximum length of
> 256 characters. However, format width in line 105 above could prevent all
> 256 characters to be read properly. To avoid this potential problem, the
> fmt width above should be greater than 256. '(A512)' would be a safe bet
> (and set length of `dummy' string to 512 as well). Otherwise there can be
> unexpected problem with input line truncation.
>
>
> The following suggestions err on safe side:
>
> 3) If "-input" parameter argument is used, there is no need for input file
> copying. Why is it still copied anyway?
>
> 4) Also, the name of the temporary file should probably be other than "
> input_tmp.in". It is better to use randomized filename (e.g. C function
> tmpnam or mkstemp) or make this file in "wfcdir" rather than current
> directory. This practice will get rid of possible race conditions or
> unintended overwriting of user's file by the same name.
>
> Thanks,
> --
> Wirawan Purwanto
> Research Scientist
> College of William and Mary
> Physics Department
> Williamsburg, VA 23187
>
>
>
>
> --
> Wirawan Purwanto
> Research Scientist
> College of William and Mary
> Physics Department
> Williamsburg, VA 23187
>
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>
>
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