Adds nonallocating versions of fftshift and ifftshift with the

corresponding tests. Fixes #62.

Author: Grigorii Starkov

src/definitions.jl

@@ -364,6 +364,17 @@ function fftshift(x, dim = 1:ndims(x))
     circshift(x, s)
 end
 
+"""
+	fftshift!(dest, src, [dim])
+
+Nonallocating version of [`fftshift`](@ref). Stores the result of the shift of the `src` array into the `dest` array.
+"""
+function fftshift!(dest, src, dim = 1:ndims(src))
+	@assert size(dest)==size(src)
+    s = ntuple(d -> d in dim ? div(size(dest,d),2) : 0, Val(ndims(dest)))
+    circshift!(dest, src, s)
+end
+
 """
     ifftshift(x, [dim])
 
@@ -384,6 +395,17 @@ function ifftshift(x, dim = 1:ndims(x))
     circshift(x, s)
 end
 
+"""
+	ifftshift!(dest, src, [dim])
+
+Nonallocating version of [`ifftshift`](@ref). Stores the result of the shift of the `src` array into the `dest array`.
+"""
+function ifftshift!(dest, src, dim = 1:ndims(src))
+	@assert size(dest)==size(src)
+    s = ntuple(d -> d in dim ? -div(size(src,d),2) : 0, Val(ndims(src)))
+    circshift!(dest, src, s)
+end
+
 ##############################################################################
 
 

test/runtests.jl

@@ -103,20 +103,37 @@ end
     @test @inferred(AbstractFFTs.fftshift([1 2 3])) == [3 1 2]
     @test @inferred(AbstractFFTs.fftshift([1, 2, 3])) == [3, 1, 2]
     @test @inferred(AbstractFFTs.fftshift([1 2 3; 4 5 6])) == [6 4 5; 3 1 2]
+	a = [0 0 0]
+	b = [0, 0, 0]
+	c = [0 0 0; 0 0 0]
+	@test (AbstractFFTs.fftshift!(a, [1 2 3]); a == [3 1 2])
+	@test (AbstractFFTs.fftshift!(b, [1, 2, 3]); b == [3, 1, 2])
+    @test (AbstractFFTs.fftshift!(c, [1 2 3; 4 5 6]); c == [6 4 5; 3 1 2])
 
     @test @inferred(AbstractFFTs.fftshift([1 2 3; 4 5 6], 1)) == [4 5 6; 1 2 3]
     @test @inferred(AbstractFFTs.fftshift([1 2 3; 4 5 6], ())) == [1 2 3; 4 5 6]
     @test @inferred(AbstractFFTs.fftshift([1 2 3; 4 5 6], (1,2))) == [6 4 5; 3 1 2]
     @test @inferred(AbstractFFTs.fftshift([1 2 3; 4 5 6], 1:2)) == [6 4 5; 3 1 2]
+	@test (AbstractFFTs.fftshift!(c, [1 2 3; 4 5 6], 1); c == [4 5 6; 1 2 3])
+	@test (AbstractFFTs.fftshift!(c, [1 2 3; 4 5 6], ()); c == [1 2 3; 4 5 6])
+	@test (AbstractFFTs.fftshift!(c, [1 2 3; 4 5 6], (1,2)); c == [6 4 5; 3 1 2])
+	@test (AbstractFFTs.fftshift!(c, [1 2 3; 4 5 6], 1:2); c == [6 4 5; 3 1 2])
 
     @test @inferred(AbstractFFTs.ifftshift([1 2 3])) == [2 3 1]
     @test @inferred(AbstractFFTs.ifftshift([1, 2, 3])) == [2, 3, 1]
     @test @inferred(AbstractFFTs.ifftshift([1 2 3; 4 5 6])) == [5 6 4; 2 3 1]
+	@test (AbstractFFTs.ifftshift!(a, [1 2 3]); a == [2 3 1])
+    @test (AbstractFFTs.ifftshift!(b, [1, 2, 3]); b == [2, 3, 1])
+    @test (AbstractFFTs.ifftshift!(c, [1 2 3; 4 5 6]); c == [5 6 4; 2 3 1])
 
     @test @inferred(AbstractFFTs.ifftshift([1 2 3; 4 5 6], 1)) == [4 5 6; 1 2 3]
     @test @inferred(AbstractFFTs.ifftshift([1 2 3; 4 5 6], ())) == [1 2 3; 4 5 6]
     @test @inferred(AbstractFFTs.ifftshift([1 2 3; 4 5 6], (1,2))) == [5 6 4; 2 3 1]
     @test @inferred(AbstractFFTs.ifftshift([1 2 3; 4 5 6], 1:2)) == [5 6 4; 2 3 1]
+	@test (AbstractFFTs.ifftshift!(c, [1 2 3; 4 5 6], 1); c == [4 5 6; 1 2 3])
+	@test (AbstractFFTs.ifftshift!(c, [1 2 3; 4 5 6], ()); c == [1 2 3; 4 5 6])
+	@test (AbstractFFTs.ifftshift!(c, [1 2 3; 4 5 6], (1,2)); c == [5 6 4; 2 3 1])
+	@test (AbstractFFTs.ifftshift!(c, [1 2 3; 4 5 6], 1:2); c == [5 6 4; 2 3 1])
 end
 
 @testset "FFT Frequencies" begin