Spatial Experience

Spatial provides ForEach as a map operator over memory. You can write:

Foreach(1 until 16 par 1){i => s(i) = s(i - 1) + 1}

which is equivalent to the following in Seashell

for (let i = 1..16) unroll 1 {
  s[i] := s[i - 1] + 1;
}

Note that this seashell program doesn’t typecheck, but is compiled by Spatial. However, Spatial doesn’t stop the programmer from writing:

Foreach(1 until 16 par 3){i => s(i) = s(i - 1) + 1}

and naively the following when s is all 0:

0 1 1 1 2 1 1 2 1 1 2 1 1 2 1 1

This shouldn’t happen in Seashell. The larger theorem we want is: