add squeeze and unsqueeze

source/mir/algorithm/iteration.d

@@ -60,7 +60,6 @@ import std.traits;
 
 @optmath:
 
-
 /+
 Bitslice representation for accelerated bitwise algorithm.
 1-dimensional contiguousitslice can be split into three chunks: head bits, body chunks, and tail bits.

source/mir/ndslice/topology.d

@@ -3918,7 +3918,7 @@ template byDim(Dimensions...)
  n-dimensional slice ipacked to allow iteration by dimension
  +/
  @optmath auto byDim(Iterator, size_t N, SliceKind kind)
-  (Slice!(Iterator, N, kind) slice)
+ (Slice!(Iterator, N, kind) slice)
  {
  import mir.ndslice.topology : ipack;
  import mir.ndslice.internal : DimensionsCountCTError;
@@ -4240,6 +4240,62 @@ version(mir_test) unittest
  assert(x == slice);
 }
 
+/++
+Adds outer dimension length of 1.
++/
+Slice!(Iterator, N + 1, kind) addOuterDim(Iterator, size_t N, SliceKind kind)(Slice!(Iterator, N, kind) slice)
+{
+ import mir.utility: swap;
+ typeof(return) ret;
+ ret._lengths[0 .. N] = slice._lengths;
+ ret._lengths[N] = 1;
+ static if (kind != SliceKind.contiguous)
+ ret._strides[0 .. $ - 1] = slice._strides;
+ swap(ret._iterator, slice._iterator);
+ return ret;
+}
+
+///
+version (mir_test) 
+@safe pure nothrow @nogc
+unittest
+{
+ // [0, 1, 2] -> [[0, 1, 2]]
+ assert([3].iota.addOuterDim == [3, 1].iota);
+ assert([3].iota.universal.addOuterDim == [3, 1].iota);
+ assert([3, 4].iota.addOuterDim == [3, 4, 1].iota);
+ assert([3, 4].iota.canonical.addOuterDim == [3, 4, 1].iota);
+ assert([3, 4].iota.universal.addOuterDim == [3, 4, 1].iota);
+}
+
+/++
+Adds inner dimension length of 1.
++/
+Slice!(Iterator, N + 1, kind) addInnerDim(Iterator, size_t N, SliceKind kind)(Slice!(Iterator, N, kind) slice)
+{
+ import mir.utility: swap;
+ typeof(return) ret;
+ ret._lengths[1 .. N + 1] = slice._lengths;
+ ret._lengths[0] = 1;
+ static if (kind != SliceKind.contiguous)
+ ret._strides[1 .. $] = slice._strides;
+ swap(ret._iterator, slice._iterator);
+ return ret;
+}
+
+///
+version (mir_test) 
+@safe pure nothrow @nogc
+unittest
+{
+ // [0, 1, 2] -> [[0], [1], [2]]
+ assert([3].iota.addInnerDim == [1, 3].iota);
+ assert([3].iota.universal.addInnerDim == [1, 3].iota);
+ assert([3, 4].iota.addInnerDim == [1, 3, 4].iota);
+ assert([3, 4].iota.canonical.addInnerDim == [1, 3, 4].iota);
+ assert([3, 4].iota.universal.addInnerDim == [1, 3, 4].iota);
+}
+
 /++
 Field (element's member) projection.