Difference between revisions of "Grep binary files for ascii text"
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| − | The phasta files (restart and geombc) | + | The phasta files (restart and geombc) include ascii headers, potentially (but not necessarily) followed by an associated binary block of data. A good example is the solution field in a restart file whose header typically looks like this: |
| − | Listing the headers included in your phasta files may be very useful. | + | |
| + | solution : < 60193 > 1254 6 0 | ||
| + | |||
| + | For the short story, | ||
| + | * if the number between <> is larger than 0, it means this header is followed by a data block in binary format. In this case, this number between <> represents the size of the data block in bytes -1. | ||
| + | * The following numbers are peculiar to the header but for most of the fields in the restart files, the first number after the > sign represents the number of vertices in the considered mesh part (here 1254). | ||
| + | * Then, 6 represents the number of variables per nodes. | ||
| + | * Finally the last number (0 here) is the time step. | ||
| + | Do the math: 1254 vertices * 6 variables per vertex * 8 bytes for a double = 60194. | ||
| + | |||
| + | Listing the headers included in your phasta files may be very useful. For that purpose, use the following command for instance: | ||
| + | |||
| + | grep -a ' : < ' restart.0.1 | ||
| + | |||
| + | It will search for the ascii text ' : < ' (space : space < space) in the hybrid ascii - binary file restart.0.1. The output will look like this for instance: | ||
| + | |||
| + | byteorder magic number : < 5 > 1 | ||
| + | number of modes : < 0 > 1254 | ||
| + | number of variables : < 0 > 6 | ||
| + | solution : < 60193 > 1254 6 0 | ||
| + | mapping_partid : < 10033 > 1254 1 0 | ||
| + | mapping_vtxid : < 10033 > 1254 1 0 | ||
Revision as of 18:09, 26 February 2015
The phasta files (restart and geombc) include ascii headers, potentially (but not necessarily) followed by an associated binary block of data. A good example is the solution field in a restart file whose header typically looks like this:
solution : < 60193 > 1254 6 0
For the short story,
- if the number between <> is larger than 0, it means this header is followed by a data block in binary format. In this case, this number between <> represents the size of the data block in bytes -1.
- The following numbers are peculiar to the header but for most of the fields in the restart files, the first number after the > sign represents the number of vertices in the considered mesh part (here 1254).
- Then, 6 represents the number of variables per nodes.
- Finally the last number (0 here) is the time step.
Do the math: 1254 vertices * 6 variables per vertex * 8 bytes for a double = 60194.
Listing the headers included in your phasta files may be very useful. For that purpose, use the following command for instance:
grep -a ' : < ' restart.0.1
It will search for the ascii text ' : < ' (space : space < space) in the hybrid ascii - binary file restart.0.1. The output will look like this for instance:
byteorder magic number : < 5 > 1 number of modes : < 0 > 1254 number of variables : < 0 > 6 solution : < 60193 > 1254 6 0 mapping_partid : < 10033 > 1254 1 0 mapping_vtxid : < 10033 > 1254 1 0
