update pyramid indices to compile only once

pi.jl

@@ -1,16 +1,27 @@
 using Base.Cartesian
+using ResumableFunctions
 
-function pi2(dims::Int, tensize::Int)
-    multinds = Tuple{fill(Int, dims)...,}[]
+struct PyramidIndices{N}
+    size::Int
+end
+
+@generated function _all_indices(p::PyramidIndices{N}) where {N}
     quote
-        @nloops $dims i x -> (x==dims) ? (1:tensize) : (i_{x+1}:tensize) begin
-            @inbounds multind = @ntuple $dims x -> i_{dims-x+1}
-            push!($multinds, multind)
+        # multinds = Tuple{fill(Int, $N)...,}[]
+        tensize = p.size
+        @nloops $N i x -> (x==$N) ? (1:tensize) : (i_{x+1}:tensize) begin
+            @inbounds multind = @ntuple $N x -> i_{$N-x+1}
+            @yield multind
+            # push!(multinds, multind)
         end
+        # multinds
     end
-    multinds
 end
 
+function pi2(dims, tensize)
+    p = PyramidIndices{dims}(tensize)
+    return _all_indices(p)
+end
 
 a = rand(2,2,2)
 dims, tensize = ndims(a), size(a, 1)
@@ -23,11 +34,14 @@ dims, tensize = ndims(b), size(b, 1)
 @time pi2(dims, tensize)
 @time pi2(dims, tensize)
 
+@show pi2(dims, tensize)
+
 c = rand(4,4,4,4)
 dims, tensize = ndims(c), size(c, 1)
 @time pi2(dims, tensize)
 @time pi2(dims, tensize)
 
+@show "asdasd"
 @time d = rand(10, 100, 100, 100, 100)
 dims, tensize = ndims(d), size(d, 1)
 @time pi2(dims, tensize)
@@ -39,4 +53,3 @@ dims, tensize = ndims(e), size(e, 1)
 @time pi2(dims, tensize)
 
 
-@show pi2(dims, tensize)

src/symmetrictensor.jl

@@ -29,6 +29,22 @@ mutable struct SymmetricTensor{T <: AbstractFloat, N}
     end
 end
 
+struct PyramidIndices{N}
+  size::Int
+end
+
+@generated function _all_indices(p::PyramidIndices{N}) where {N}
+  quote
+      multinds = Tuple{fill(Int, $N)...,}[]
+      tensize = p.size
+      @nloops $N i x -> (x==$N) ? (1:tensize) : (i_{x+1}:tensize) begin
+          @inbounds multind = @ntuple $N x -> i_{$N-x+1}
+          push!(multinds, multind)
+      end
+      multinds
+  end
+end
+
 """
     unfold(ar::Array{T,N}, mode::Int)
 
@@ -123,14 +139,8 @@ julia> pyramidindices(2,3)
 ```
 """
 function pyramidindices(dims::Int, tensize::Int)
-  quote
-      multinds = Tuple{fill(Int, dims)...,}[]
-      @nloops $dims i x -> (x==$dims) ? (1:tensize) : (i_{x+1}:tensize) begin
-          @inbounds multind = @ntuple $dims x -> i_{$dims-x+1}
-          push!(multinds, multind)
-      end
-      multinds
-  end
+  p = PyramidIndices{dims}(tensize)
+  return _all_indices(p)
 end
 
 """