I deleted the .txt file header file but nothing good happened ! On the other hand, I transformed the .txt file into a .csv file and it worked fine.Note that when saving a matrix to .txt with gretl, it seems the only
"problematic" part of the file is the header line like "mymatrix (2x2)".
Otherwise it's an almost perfect csv file. So as a workaround you could
comment out or delete the header.
The problem is with matrix whose rows' number exceeds the number of observation in the data file. You can't save the rows as series.But what do you really want to do? If your matrices really represent
data series / variables, I think you can convert them to series via a
console command (check the user guide) and then normally save them as
series to a .gdt file.