# File handling

The FILE directive is used to open permanent files, which can be used for later restarts. The syntax in Molpro94 and later versions is

FILE,file,name,[status]

file is the logical Molpro file number (1-9). name is the file name (will be converted to lower case). status can be one of the following:

• UNKNOWN A permanent file is opened. If it exists, it is automatically restarted. This is the default.
• OLD Same effect as UNKNOWN. No error occurs if the file does not exist.
• NEW A permanent file is opened. If it already exists, it is erased and not restarted.
• ERASE Same effect as NEW.
• SCRATCH A temporary file is opened. If it already exists, it is erased and not restarted. After the job has finished, the file is no longer existent.
• DELETE Same effect as SCRATCH.

Note that RESTART is now the default for all permanent files. All temporary files are usually allocated automatically where needed. I/O buffers are allocated at the top of the dynamic memory, and the available memory decreases by the size of the buffers. The MEMORY card must therefore be presented before the first FILE card!

Examples:

• FILE,1,H2O.INT allocates permanent file 1 with name H2O.INT. Previous information on the file is recovered.
• FILE,2,H2O.WFU,NEW allocates permanent file 2 with name H2O.WFU. All previous information on the file is erased.

Note that filenames are converted to lower case on unix machines.

DELETE,file1, file2, …

Deletes the specified files. file refers to the logical Molpro file numbers as specified on the FILE card.

ERASE,file1, file2, …

Erases the specified files. file refers to the logical Molpro file numbers as specified on the FILE card.

The DATA command can be used to modify the Molpro binary files.

• UNIT Alias for NPL (should never be used)
• RENAME,rec1,rec2 used to rename rec1 to rec2. rec1 and rec2 must be given in the form name.ifil, where ifil is the number of a Molpro binary file (alias for NAME).
• TRUNCATE,nen used to truncate files after nen-1 records (alias for NEN).
• TRUNCATE,rec used to truncate before record rec. rec must be given in the form name.ifil, where ifil is the number of a Molpro binary file.
• COUNT Alias for NRE (presently not used)
• COPY,rec1,rec2 Copies record rec1 to rec2. rec1 and rec2 must be given in the form nam1.ifil1, nam2.ifil2. If nam2=0, nam2=nam1. If nam1=0, all records are copied from file ifil1 to file ifil2.

PUNCH,filename,[REWIND]

Opens punch file named filename. If this file already exists, it is appended, unless the REWIND or NEW option is specified; in that case, any previous information on the punch file is overwritten. See FILE for machine dependent interpretation of filename. The punch file contains all important results (geometries, energies, dipole, transition moments etc). It can be read by a separate program READPUN, which can produce tables in user supplied format.

Example:

• PUNCH,H2O.PUN allocates punch file H2O.PUN

Note that the file name is converted to lower case on unix machines.

The GPARAM card allows to change MOLPRO system parameters. This should only be used by experts!

GPARAM,option=value,$\ldots$

The following options can be given in any order.

• NOBUFF if present, disable system buffering
• LSEG disk sector length
• INTREL number of integer words per real word (should never be modified!)
• IBANK number of memory banks. Default is 2, which should always be o.k.
• IVECT 0=scalar, 1=vector machine
• MINVEC minimum vector length for call to mxmb
• LTRACK page size in buffer routines (must be multiple of lseg)
• LENBUF length of integral buffer (file 1)
• NTR length of integral records (must be multiple of $3 \cdot$ltrack)
• LTR disk sector length assumed in CI (default 1 is reasonable)
• NCACHE machine cache size in bytes
• IASYN if nonzero, use asynchronous I/O on CONVEX
• MXMBLK column/row block size for mxma
• MXMBLN link block size for mxma
• NCPUS maximum number of cpus to be used in multitasking
• MINBR1 min number of floating point ops per processor
• MXDMP highest file number to be treated as dump file with full functionality ($1 \le.$ MXDMP$\le.3$).

The MXDMP option is for experts only! This prevents basis and geometry information from being written to dump files with higher file number than the given value, and can sometimes be useful for counterpoise corrected geometry optimizations. Note that some functionality is lost by giving this option, and errors will result unless all input is correct!