No input is required, other than the command line with file assignments.
mtztona4 can optionally produce a run-length-encoded (RLE) format that is more compact than the original NA4 format; however the old version of na4tomtz cannot read the new format (it will echo the input data to standard output without converting it). Only the current version of na4tomtz can convert the RLE format back to MTZ (of course the current na4tomtz can also convert the old NA4 format to MTZ).
To select the RLE option in mtztona4, define the environment variable: CCP4_RLENA4 (na4tomtz does not require this to be defined as it detects automatically NA4 or RLE format).
N.B. With the current version of the CCP4 library there is little need for the NA4 format since MTZ files may be read transparently on different architectures (though it is useful for sending data by e-mail).
After an ASCII readable header is output to HKLOUT the reflection data are stored as characters. A sample of an output file is given below:
u000200000002Kk0eU0000000000000000000000000000000000 u000200040005ts0B000000000007hc07w000000000000000000 u000200080003Kk0K80000000000000000000000000000000000
If the MTZ file is converted so that unmeasured items are flagged (F's with zero sigmas changed to NaN's), and the CCP4_RLENA4 option is activated, the same piece of output looks like this:
u%02*22Kk0eU%.7 u%02%04%05ts0B%0.17hc07w%.3 u%02%08%03Kk0K8%.7
-rw-r--r-- 1 programs 169684 Mar 2 13:14 toxd.mtz -rw-r--r-- 1 programs 172130 Mar 3 12:12 toxd.na4 -rw-r--r-- 1 programs 110437 Mar 3 12:14 toxd_flag.rle
mtztona4 hklin toxd hklout toxd.na4 na4tomtz hklin toxd.na4 hklout toxd