Change softmax iterator, also make example compile

Author: mratsim

examples/ex06_shakespeare_generator.nim

@@ -56,7 +56,7 @@ const
 #
 # ################################################################
 
-func strToTensor(str: string|TaintedString): Tensor[PrintableIdx] =
+proc strToTensor(str: string|TaintedString): Tensor[PrintableIdx] =
   result = newTensor[PrintableIdx](str.len)
 
   # For each x in result, map the corresponding char index

src/arraymancer/laser/strided_iteration/foreach_common.nim

@@ -46,7 +46,6 @@ proc aliasTensor(id: int, tensor: NimNode): tuple[alias: NimNode, isVar: NimNode
     for i in 2 ..< tensor.len:
       t.add tensor[i]
 
-  var alias = ""
   let isVar = block:
     # Handle slicing cases like foo[0..<1, 0..<2]
     # that do not return `var` but are technically `var`
@@ -57,16 +56,18 @@ proc aliasTensor(id: int, tensor: NimNode): tuple[alias: NimNode, isVar: NimNode
     else:
       quote do: isVar(`t`)
 
-  while t.kind in {nnkDotExpr, nnkBracketExpr}:
-    if t[0].kind notin {nnkIdent, nnkSym}:
-      error "Expected a field name but found \"" & t[0].repr()
-    alias.add $t[0]
-    if t.kind == nnkBracketExpr and validIdentifier(t[1].repr()):
-      alias.add $t[1]
-    alias.add "_"
-    t = t[1]
+  proc flattenedName(node: NimNode): string =
+    if node.kind in {nnkDotExpr, nnkBracketExpr}:
+      result = flattenedName(node[0])
+      result &= '_'
+      result &= flattenedName(node[1])
+    elif node.kind in {nnkIdent, nnkSym}:
+      result = $node
+    else:
+      error "Expected a field nameor dot expression or array access but found \"" &
+        t.repr()
 
-  alias &= $t
+  let alias = flattenedName(t)
 
   return (newIdentNode($alias & "_alias" & $id & '_'), isVar)
 

src/arraymancer/nn_primitives/nnp_softmax.nim

@@ -29,10 +29,11 @@ proc softmax*[T](input: Tensor[T]): Tensor[T] {.noInit.} =
   let batch_size = input.shape[0]
   result = zeros_like(input)
 
+  # TODO: the performance of nested parallel regions is highly suspect
   for i in 0||(batch_size-1):
     let (max, sumexp) = input[i, _].streaming_max_sumexp
 
     var res_slice = result[i, _]
 
-    apply2_inline(res_slice, input[i, _]):
-      stable_softmax(y, max, sumexp)
+    forEachSerial r in res_slice, inpi in input[i, _]:
+      r = stable_softmax(inpi, max, sumexp)

src/arraymancer/nn_primitives/nnp_softmax_cross_entropy.nim

@@ -185,13 +185,14 @@ proc sparse_softmax_cross_entropy_backward*[T; Idx: SomeNumber or byte or char o
   for i, truth_idx in enumerate(target):
     result[i, int(truth_idx)] = -1
 
+  # TODO: the performance of nested parallel regions is highly suspect
   for i in 0||(batch_size-1):
     let (max, sumexp) = cached_tensor[i, _].streaming_max_sumexp
 
     var res_slice = result[i, _]
 
-    apply2_inline(res_slice, cached_tensor[i, _]):
-      grad * (stable_softmax(y, max, sumexp) + x) / T(batch_size)
+    forEachSerial r in res_slice, ci in cached_tensor[i, _]:
+      r = grad * (stable_softmax(ci, max, sumexp) + r) / T(batch_size)
 
 
 # ################################################