Added parallel fftshift

doc/fftw3.html

@@ -661,7 +661,7 @@ <h1><a class="toc-backref" href="#12">Procs</a></h1>
 <dt><pre><span class="Keyword">proc</span> <a href="#circshift%2CTensor%5BT%5D%2Cseq%5Bint%5D"><span class="Identifier">circshift</span></a><span class="Other">[</span><span class="Identifier">T</span><span class="Other">]</span><span class="Other">(</span><span class="Identifier">t</span><span class="Other">:</span> <span class="Identifier">Tensor</span><span class="Other">[</span><span class="Identifier">T</span><span class="Other">]</span><span class="Other">;</span> <span class="Identifier">shift</span><span class="Other">:</span> <span class="Identifier">seq</span><span class="Other">[</span><span class="Identifier">int</span><span class="Other">]</span><span class="Other">)</span><span class="Other">:</span> <span class="Identifier">Tensor</span><span class="Other">[</span><span class="Identifier">T</span><span class="Other">]</span></pre></dt>
 <dd>
 
-Circshift
+Generic Circshift
 
 </dd>
 <a id="fftshift,Tensor[T]"></a>
@@ -1440,7 +1440,7 @@ <h1><a class="toc-backref" href="#12">Procs</a></h1>
       <div class="twelve-columns footer">
         <span class="nim-sprite"></span>
         <br/>
-        <small style="color: var(--hint);">Made with Nim. Generated: 2020-06-07 15:21:42 UTC</small>
+        <small style="color: var(--hint);">Made with Nim. Generated: 2020-06-10 12:19:53 UTC</small>
       </div>
     </div>
   </div>

fftw3.nimble

@@ -1,6 +1,6 @@
 # Package
 
-version       = "0.2.2"
+version       = "0.2.3"
 author        = "rcaillaud"
 description   = "Nim FFTW bindings"
 license       = "LGPL-2.1"

src/fftw3.nim

@@ -98,10 +98,44 @@ type
   fftw_plan* = pointer
 
 # Utility procedures
+proc circshift_impl[T](t: Tensor[T], xshift: int, yshift: int, zshift: int): Tensor[T]=
+  assert(t.rank == 3)
+  var X = t.shape[0]
+  var Y = t.shape[1]
+  var Z = t.shape[2]
 
-proc circshift*[T](t: Tensor[T], shift: seq[int]): Tensor[T]=
-  ## Circshift
-  assert(t.rank == shift.len)
+  result = newTensor[T](t.shape.toSeq)
+  for i in 0||(X-1):
+    var ii = (i + xshift) mod X
+    for j in 0||(Y-1):
+      var jj = (j + yshift) mod Y
+      for k in 0||(Z-1):
+        var kk = (k + zshift) mod Z
+        result[ii, jj, kk] = t[i, j, k]
+
+proc circshift_impl[T](t: Tensor[T], xshift: int, yshift: int): Tensor[T]=
+  assert(t.rank == 2)
+  var X = t.shape[0]
+  var Y = t.shape[1]
+
+  result = newTensor[T](t.shape.toSeq)
+  for i in 0||(X-1):
+    var ii = (i + xshift) mod X
+    for j in 0||(Y-1):
+      var jj = (j + yshift) mod Y
+      result[ii, jj] = t[i, j]
+
+proc circshift_impl[T](t: Tensor[T], xshift: int): Tensor[T]=
+  assert(t.rank == 1)
+  var X = t.shape[0]
+
+  result = newTensor[T](t.shape.toSeq)
+  for i in 0||(X-1):
+    var ii = (i + xshift) mod X
+    result[ii] = t[i]
+
+# TODO : Generic implementation in parallel
+proc circshift_impl[T](t: Tensor[T], shift: seq[int]): Tensor[T]=
   let shape = t.shape.toSeq
   result = newTensor[T](t.shape.toSeq)
   for coord, values in t:
@@ -110,6 +144,19 @@ proc circshift*[T](t: Tensor[T], shift: seq[int]): Tensor[T]=
       newcoord[i] = (coord[i]+shift[i]) mod shape[i]
     result.atIndexMut(newcoord, values)
 
+proc circshift*[T](t: Tensor[T], shift: seq[int]): Tensor[T]=
+  ## Generic Circshift
+  assert(t.rank == shift.len)
+  case t.rank
+  of 1:
+    result = circshift_impl(t, shift[0])
+  of 2:
+    result = circshift_impl(t, shift[0], shift[1])
+  of 3:
+    result = circshift_impl(t, shift[0], shift[1], shift[2])
+  else:
+    result = circshift_impl(t, shift)
+
 proc fftshift*[T](t: Tensor[T]): Tensor[T]=
   ## Calculate fftshift using circshift
   let xshift = t.shape[0] div 2