You saved a Vec to the file, not a Mat.
> On Dec 3, 2018, at 1:38 PM, Sajid Ali via petsc-users
> <petsc-users@mcs.anl.gov> wrote:
>
> Hi,
>
> I ran ex10 from /vec/examples/tutorials and saved the matrix in binary format.
>
> Looking at the matrix in binary using xxd, I see
>
> [sajid@xrm temp]$ xxd -b vector.dat
> 0000000: 00000000 00010010 01111011 01001110 00000000 00000000 ..{N..
> 0000006: 00000000 00010100 00000000 00000000 00000000 00000000 ......
> 000000c: 00000000 00000000 00000000 00000000 00111111 11110000 ....?.
> 0000012: 00000000 00000000 00000000 00000000 00000000 00000000 ......
> 0000018: 01000000 00000000 00000000 00000000 00000000 00000000 @.....
> 000001e: 00000000 00000000 01000000 00001000 00000000 00000000 ..@...
> 0000024: 00000000 00000000 00000000 00000000 01000000 00010000 ....@.
> 000002a: 00000000 00000000 00000000 00000000 00000000 00000000 ......
> 0000030: 01000000 00010100 00000000 00000000 00000000 00000000 @.....
> 0000036: 00000000 00000000 01000000 00011000 00000000 00000000 ..@...
> 000003c: 00000000 00000000 00000000 00000000 01000000 00011100 ....@.
> 0000042: 00000000 00000000 00000000 00000000 00000000 00000000 ......
> 0000048: 01000000 00100000 00000000 00000000 00000000 00000000 @ ....
> 000004e: 00000000 00000000 01000000 00100010 00000000 00000000 ..@"..
> 0000054: 00000000 00000000 00000000 00000000 01000000 00100100 ....@$
> 000005a: 00000000 00000000 00000000 00000000 00000000 00000000 ......
> 0000060: 01000000 00100110 00000000 00000000 00000000 00000000 @&....
> 0000066: 00000000 00000000 01000000 00101000 00000000 00000000 ..@(..
> 000006c: 00000000 00000000 00000000 00000000 01000000 00101010 ....@*
> 0000072: 00000000 00000000 00000000 00000000 00000000 00000000 ......
> 0000078: 01000000 00101100 00000000 00000000 00000000 00000000 @,....
> 000007e: 00000000 00000000 01000000 00101110 00000000 00000000 ..@...
> 0000084: 00000000 00000000 00000000 00000000 01000000 00110000 ....@0
> 000008a: 00000000 00000000 00000000 00000000 00000000 00000000 ......
> 0000090: 01000000 00110001 00000000 00000000 00000000 00000000 @1....
> 0000096: 00000000 00000000 01000000 00110010 00000000 00000000 ..@2..
> 000009c: 00000000 00000000 00000000 00000000 01000000 00110011 ....@3
> 00000a2: 00000000 00000000 00000000 00000000 00000000 00000000 ......
>
>
> The format of the binary file is supposed to be
> MAT_FILE_CLASSID, num_rows, num_cols, -1 followed by data.
>
> Converting the first 4 bytes (32 bits) of binary to int, the number
> 00000000000100100111101101001110 becomes 1211214, but the value of
> MAT_FILE_CLASSID according to the header file petscmat.h is 1211216
> (petsc@3.10.2.1 built without complex support). What causes this discrepancy
> ?
>
> Also, what are the special characters at the end of every line ? Am i not
> reading the binary file correctly ?
>
>
> Thank You,
> Sajid Ali
> Applied Physics
> Northwestern University
