transmesh generates significantly larger binary file from the original ASCII file

[CsatiZoltan]

Hi,

We have a dummy.sol file, with the following content:

MeshVersionFormatted 2

Dimension 3

SolAtVertices
47594
5 1 1 1 1 1
0 0 0 101300 1.20387216431
...
End

Replace the ... with the previous line 47593 times for the real content. In fact, this file represents the (uniform) initial field of a simulation. Its size is

$ du dummy.sol
1256    dummy.sol

Calling transmesh (version TRANSMESH v4.0, feb 27 2014) on it results in the binary file dummy.solb, which is much larger:

$ du dummy.solb
1860    dummy.solb

Tested it with the version from the master branch too ( TRANSMESH v5.2, july 19 2017, Loic MARECHAL / INRIA), no change:

$ du dummy2.solb
1860    dummy2.solb

What is the reason for the significant file size increase in the binary format?

[LoicMarechal]

Hi Zoltan,
your binary file is bigger than the ASCII one because it is full of zeroes.
Usually ASCII files are bigger than binary ones except when using small integers which take 2 or 3 bytes while still using 8 bytes in double precision binary.
Your file if full of 0 that take two bytes (the "0" and the following space separator.
A binary "0" uses 8 bytes ...

[CsatiZoltan]

Thank you.