Remove unnecessary array allocations and devil numbers

[zhaog6]

With KSPSolve, it is unnecessary to manually allocate memory when declaring FreeFEM array variables.

[prj-]

Is there a specific reason why you'd want not to specify the sizes? It will still be done down the road (in the .cpp) if it's not done sooner (in the .edp). Also, just FYI, you don't need to close a PR and reopen a new one just to change branch destination, you can just edit the original PR, cf. GitHub documentation.

[zhaog6]

Is there a specific reason why you'd want not to specify the sizes? It will still be done down the road (in the .cpp) if it's not done sooner (in the .edp)

Because sometimes I can't remember whether I need to manually allocate memory for these arrays before using some functions such as ChangeNumbering, MatMult and KSPSolve, when I encounter this situation, I often have to write another example to test. But a short break in the middle may make the program not very smooth. So I want to have a unified declaration with these arrays and the allocation of array memory is handled by KSPSolve. This is just a feeling for me.

[zhaog6]

you don't need to close a PR and reopen a new one just to change branch destination, you can just edit the original PR, cf. GitHub documentation.

Okay.

[zhaog6]

Thanks for your review and advice.