Update docs

README.fakedata.md

@@ -7,7 +7,7 @@ it generates fake sizes messages and can be scaled to run on any number of MPI
 ranks.
 
 ```
-Usage: ./swiftmpifakestepsim [options] nr_messages logfile.dat
+Usage: ./swiftmpifakestepsim [vds:rgx:c:o:f:z] nr_messages logfile.dat
  options: -v verbose, -d data check, -s size (bytes/scale), 
          -f <1|2> randomize injection order, 1 == just sends, 2 == sends and recvs
         [-r uniform random from 1 to size, | 
@@ -15,6 +15,7 @@ Usage: ./swiftmpifakestepsim [options] nr_messages logfile.dat
         -r -c <file> use cdf from file, size is a scale factor., |
         -r -o <file> use occurence sample of values in a file, size is a scale factor.,] 
         -x random seed
+        -z output log in standard format, i.e. can be used as input to swiftmpistepsim
 ```
 
 To use a fixed message size just use `-s`.
@@ -46,5 +47,9 @@ sizes of the packets, this is used to form a cdf:
 Other options are useful to make sure that the randoms are different, `-x` and
 that they run in different order `-f <1|2>`.
 
+The output from this program can be used as logs for the standard
+swiftmpistepsim program using -z flag. This drops some new fields.
+
+
 Peter W. Draper 24 Apr 2023
 ---------------------------