ae.utils.parallelism: Add a questionable refactoring

CyberShadow · May 7, 2024 · 6e3cf4d · 6e3cf4d
1 parent 6d72314
commit 6e3cf4d
Showing 1 changed file with 19 additions and 22 deletions.
diff --git a/utils/parallelism.d b/utils/parallelism.d
@@ -94,35 94,37 @@ version(ae_unittest) unittest
  assert(!parallelEqual(a, b));
 }
 
 // ************************************************************************
 
 private auto parallelChunkOffsets(size_t length)
 {
  size_t numChunks = min(length, totalCPUs);
  return (numChunks   1).iota.map!(chunkIndex => chunkIndex * length / numChunks);
 }
 
 /// Split a range into chunks, processing each chunk in parallel.
 /// Returns a dynamic array containing the result of calling `fun` on each chunk.
 /// `fun` is called at most once per CPU core.
 T[] parallelChunks(R, T)(R range, scope T delegate(R) fun)
 if (isRandomAccessRange!R)
 {
- auto total = range.length;
- size_t numChunks = min(total, totalCPUs);
  auto offsets = parallelChunkOffsets(range.length);
  size_t numChunks = offsets.length - 1;
  auto result = new T[numChunks];
  foreach (chunkIndex; numChunks.iota.parallel(1))
- result[chunkIndex] = fun(range[
- (chunkIndex   0) * total / numChunks ..
- (chunkIndex   1) * total / numChunks
- ]);
  result[chunkIndex] = fun(range[offsets[chunkIndex] .. offsets[chunkIndex   1]]);
  return result;
 }
 
 /// ditto
 T[] parallelChunks(N, T)(N total, scope T delegate(N start, N end) fun)
 if (is(N : ulong))
 {
- size_t numChunks = min(total, totalCPUs);
  auto offsets = parallelChunkOffsets(total);
  size_t numChunks = offsets.length - 1;
  auto result = new T[numChunks];
  foreach (chunkIndex; numChunks.iota.parallel(1))
- result[chunkIndex] = fun(
- cast(N)((chunkIndex   0) * total / numChunks),
- cast(N)((chunkIndex   1) * total / numChunks),
- );
  result[chunkIndex] = fun(cast(N)offsets[chunkIndex], cast(N)offsets[chunkIndex   1]);
  return result;
 }
 
@@ -131,14 133,11 @@ auto parallelChunks(alias fun, R)(R range)
 if (isRandomAccessRange!R)
 {
  alias T = typeof(fun(range[0..0]));
- auto total = range.length;
- size_t numChunks = min(total, totalCPUs);
  auto offsets = parallelChunkOffsets(range.length);
  size_t numChunks = offsets.length - 1;
  auto result = new T[numChunks];
  foreach (chunkIndex; numChunks.iota.parallel(1))
- result[chunkIndex] = fun(range[
- (chunkIndex   0) * total / numChunks ..
- (chunkIndex   1) * total / numChunks
- ]);
  result[chunkIndex] = fun(range[offsets[chunkIndex] .. offsets[chunkIndex   1]]);
  return result;
 }
 
@@ -147,13 146,11 @@ auto parallelChunks(alias fun, N)(N total)
 if (is(N : ulong))
 {
  alias T = typeof(fun(N.init, N.init));
- size_t numChunks = min(total, totalCPUs);
  auto offsets = parallelChunkOffsets(total);
  size_t numChunks = offsets.length - 1;
  auto result = new T[numChunks];
  foreach (chunkIndex; numChunks.iota.parallel(1))
- result[chunkIndex] = fun(
- cast(N)((chunkIndex   0) * total / numChunks),
- cast(N)((chunkIndex   1) * total / numChunks),
- );
  result[chunkIndex] = fun(cast(N)offsets[chunkIndex], cast(N)offsets[chunkIndex   1]);
  return result;
 }