how can antares surport loop which index doesn't start with 0

[lethean1]

I'm trying to use antares to express the loop like this:

for(int64_t i=1; i < domain_size; ++i) {
      for(int64_t j=1; j < domain_size; ++j) {
        out(i,j) = flx(i-1,j) - flx(i,j) + fly(i,j-1) - fly(i,j);
      }
 }

and the loop indeces i and j don't start with 0. flx[N-1,M].when([-1 + N >= 0], 0.0) is not a possible solution as it violates the semantics. Any help to express this loop is appreciated !!!

[sebastienwood]

Decrease it by 1 maybe ?

for(int64_t i=0; i <= domain_size; ++i) {
      for(int64_t j=0; j <= domain_size; ++j) {
        out(i-1,j-1) = flx(i-2,j-1) - flx(i-1,j-1) + fly(i-1,j-2) - fly(i-1,j-1);
      }
 }

[ghostplant]

Hi, does this work for you?

out[N, M] = (flx[N - 1, M] - flx[N, M] + fly[N, M - 1] - fly[N, M]).when([N >= 1, M >= 1], const(0, dtype=flx.dtype()), merge_op=`any`) where N in {domain_size}, M in {domain_size}

[lethean1]

Decrease it by 1 maybe ?

for(int64_t i=0; i <= domain_size; ++i) {
      for(int64_t j=0; j <= domain_size; ++j) {
        out(i-1,j-1) = flx(i-2,j-1) - flx(i-1,j-1) + fly(i-1,j-2) - fly(i-1,j-1);
      }
 }

It seems that out(i-1,j-1) is not legal in antares, it only allows form like this : out(i,j).

[lethean1]

Hi, does this work for you?

out[N, M] = (flx[N - 1, M] - flx[N, M] + fly[N, M - 1] - fly[N, M]).when([N >= 1, M >= 1], const(0, dtype=flx.dtype()), merge_op=`any`) where N in {domain_size}, M in {domain_size}

This can work, but will result in the calculation of redundancy. Is there any other way?

[ghostplant]

Is out[N, 0] and out[0, M] not used by following operations? If they're useful, they are not regarded as redundant computation. If they are not useful, why don't you even remove those unsed space for that, making it:

out[N, M] = flx[N, M + 1] - flx[N + 1, M + 1] + fly[N + 1, M] - fly[N + 1, M + 1] where N in {domain_size - 1}, M in {domain_size - 1}