CASTEP Error abort handling
An abnormal or premature exit from a CASTEP run can have three caus.
1. CASTEP has detected an error of some kind and chon to perform a controlled abort of
the run. This may occur if
1. There is a syntax or other error in your input files
2. some condition has occurred during the run which prevents it from continuing.
This might be a check on the validity of the physics assumptions or a如何提高口语表达能力
computational constraint.c)盖章英文
escape是什么意思3. CASTEP has requested an action of the operating system (via the Fortran
run-time library) which has returned a failure status to CASTEP
2. The operating system has chon to terminate the CASTEP run and killed it. In a batch
system this may be becau it exceeded some system resource or queue cputime limit.
3. There is a bug in CASTEP and the process, or one of the parallel process has terminated
with a "gmentation violation" or "bus error" signal (UNIX and Linux) or "access violation" (windows).诗句翻译
When trying to understand the cau of the error it is important to work out which of the above three cas has occurred. In ca (1) CASTEP always writes a (hopefully) explanatory error message into one of its stderr files. The have names of the form <edname>. where <edname> is the root name of your castep run, and nnnn is a 4-digit integer showing which parallel process issued the error message (always 0001 for a rial run). They are deleted on a normal end-of-run exit. If any of the files contains an informational message that proves that CASTEP cho a controlled abort. If on the other hand all of the <edname>. files are empty that proves that the running CASTEP process were killed externally, either becau of an operating system action (ca 2) or a bug (ca 3).汉语句子翻译成英语
Further diagnosis: Cas (2) and (3)
To understand the cas you should look at the logfiles written by the batch job manager (if you are using one) which should contain some information on the reason for aborting the run. The can sometimes be verbo and cryptic; it is usually best to study the output logs of a successful run and to look for differences. You may well have to ask your systems staff to interpret the for you.
A further indication of an external abort is the prence of "core" files, which are dumped on a signal. The can sometimes be uful to a guru in further diagnosis of a bug.
Running out of memory
This is such a common error with plane-wave calculations that it merits a ction of its own.diver
HEAP Memory exceeded
If any of the . files contain the messages
* Error in allocating /variable/ in /function/ (CASTEP versions <= 4.0.1) * Out of RAM for /variable/ in /function/ (CASTEP versions >= 4.1) this means that CASTEP requested some memory from the operating system (using Fortran's ALLOCATE statement) and the request was denied, usually becau available memory has been exhausted. After checking that your input ttin
gs do not contain an error, your options are
1. to u some of CASTEP's memory-saving options eg t parameter
OPT_STRATEGY=MEMORY (or OPT_STRATEGY_BIAS to 0 or -3) and PAGE_WVFNS=-1 or PAGE_WVFNS=/max-size/
2. to find a computer with more memory to run on, (or go to your local computer shop, buy
and install some additional memory)
3. If on a parallel system, increa the number of processors for the job. This way the total
memory needed will be distributed over a larger number of process, and the requirement per processor will be smaller
STACK Memory exceeded
Due to a design limitation of linux and most unix and microsoft operating systems, there is another "memory exceeded" condition which can not be trapped by CASTEP. This occurs when the stack me
mory is exhausted, and the result is the process is killed with a "gmentation fault" on unix/linux. This is harder to diagno, but be aware that there are O/S-enforced stack limits which might be much smaller than the physical memory in the system. Google for process stack limits stacksize for more information. the shell command ulimit -s unlimited can be ud to increa stack size (bash shells).
CASTEP error messages explained
It is intended that the error messages CASTEP writes to the <edname>.6 files are as far as possible lf-explanatory. Unfortunately it is not always possible to give uful "end-ur" explanations. Here are some commonly encountered abort messages with some explanation.
* ERROR: cell_read - failure to open freeform cell file /filename/
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* Error model_continuation: Failed to open file /filename/
CASTEP was unable to open the input files for the run specified on the command line, probably becau there is no file of that name. Check your command lines and input files.
* Error in allocating /variable/ in /function/ (CASTEP versions <= 4.0.1)
* Out of RAM for /variable/ in /function/ (CASTEP versions >= 4.1)
This common error means that CASTEP ran out of memory. See ction "Running out of memory" for more information
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* Error reading wavefunction coefficients from file in wave_read_all_r/par
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This or similar messages means that CASTEP was attempting to read a continuation file but the read failed. This is commonly becau the .check file is truncated or corrupt. The wavefunction coefficients are fairly far down the file, after the parameters and cell data, and if the read got that far before failing, it is likely that the file was truncated. This can happen if the previous CASTEP run crashed or was killed while writing the .check file. Check to e if the file size is consistent with any similar .check files you may have.
* Trapped SIGINT or SIGTERM. (CASTEP versions <= 4.0.1) This message is generated by an otherwi uless signal handler in earlier versions of CASTEP. It means that CASTEP was killed by an external signal. Diagnosis should proceed as for major ca (3)
* Error check_elec_ground_state : electronic_minimisation of initial cell failed. * Error calculate_finite_basis : Convergence failed when doing finite basis t correction.
* Error in /subroutine/ - electronic_minimisation of current_cell failedconquent
Any of the messages means that the SCF convergence loop did not converge in in the maximum allowed number of iterations. If you read the end of the .castep file it ought to be obvious whether the run only just failed to converge. In that ca specifying a larger value of MAX_SCF_CYCLES in the .param file ought to work. But sometimes it is apparent that the energy is unlikely ever to converge, for example it may oscillate, or be decreasing linearly and slowly. This may indicate that the system is in a poorly-bonded or co-ordinated state, and it's best to ask advice if you don't know how to preceed.
* Error in parameters_restore: missing END_GENERAL
This can occur on a continuation run where the .check file ud for restart is incompatible with the version of CASTEP you are using. We aim for nearly full compatibility, but there are always exceptions.
