Fix some aliasing issues, and allow mul! to mutate its input since FFTW

does

Author: gaurav-arya

src/TestUtils.jl

@@ -84,7 +84,7 @@ function test_fft_backend(array_constructor; test_real=true, test_inplace=true)
             plans_to_test = [plan_fft(x, dims), inv(plan_ifft(x, dims)), 
                              AbstractFFTs.plan_inv(plan_ifft(x, dims))]
             for P in plans_to_test
-                @test mul!(similar(y), P, x_complex) ≈ fftw_fft
+                @test mul!(similar(y), P, copy(x_complex)) ≈ fftw_fft
             end
             test_inplace && (plans_to_test = vcat(plans_to_test, plan_fft!(similar(x_complex), dims)))
             for P in plans_to_test 
@@ -100,7 +100,7 @@ function test_fft_backend(array_constructor; test_real=true, test_inplace=true)
             test_inplace && (@test AbstractFFTs.bfft!(copy(y), dims) ≈ fftw_bfft)
             plans_to_test = [plan_bfft(similar(y), dims)]
             for P in plans_to_test
-                @test mul!(similar(x_complex), P, y) ≈ fftw_bfft
+                @test mul!(similar(x_complex), P, copy(y)) ≈ fftw_bfft
             end
             test_inplace && (plans_to_test = vcat(plans_to_test, plan_bfft!(similar(y), dims)))
             for P in plans_to_test
@@ -117,7 +117,7 @@ function test_fft_backend(array_constructor; test_real=true, test_inplace=true)
             plans_to_test = [plan_ifft(x, dims), inv(plan_fft(x, dims)), 
                              AbstractFFTs.plan_inv(plan_fft(x, dims))]
             for P in plans_to_test
-                @test mul!(similar(x_complex), P, y) ≈ fftw_ifft
+                @test mul!(similar(x_complex), P, copy(y)) ≈ fftw_ifft
             end
             test_inplace && (plan_to_test = vcat(plans_to_test, plan_ifft!(similar(x_complex), dims)))
             for P in plans_to_test
@@ -137,31 +137,31 @@ function test_fft_backend(array_constructor; test_real=true, test_inplace=true)
                 ]
                 ry = AbstractFFTs.rfft(x_real, dims)
                 @test ry ≈ fftw_rfft
-                for P in [plan_rfft(x_real, dims), inv(plan_irfft(ry, size(x, first(dims)), dims)), 
-                          AbstractFFTs.plan_inv(plan_irfft(ry, size(x, first(dims)), dims))]
+                for P in [plan_rfft(similar(x_real), dims), inv(plan_irfft(similar(ry), size(x, first(dims)), dims)), 
+                          AbstractFFTs.plan_inv(plan_irfft(similar(ry), size(x, first(dims)), dims))]
                     @test eltype(P) <: Real
                     @test P * x_real ≈ fftw_rfft
-                    @test mul!(similar(ry), P, x_real) ≈ fftw_rfft
+                    @test mul!(similar(ry), P, copy(x_real)) ≈ fftw_rfft
                     @test P \ (P * x_real) ≈ x_real
                     @test fftdims(P) == dims
                 end
 
                 # BRFFT
                 fftw_brfft = prod(size(x_real, d) for d in dims) .* x_real
                 @test AbstractFFTs.brfft(ry, size(x_real, first(dims)), dims) ≈ fftw_brfft
-                P = plan_brfft(ry, size(x_real, first(dims)), dims)
+                P = plan_brfft(similar(ry), size(x_real, first(dims)), dims)
                 @test P * ry ≈ fftw_brfft
-                @test mul!(similar(x_real), P, ry) ≈ fftw_brfft
+                @test mul!(similar(x_real), P, copy(ry)) ≈ fftw_brfft
                 @test P \ (P * ry) ≈ ry
                 @test fftdims(P) == dims
 
                 # IRFFT
-                fftw_irfft = x_complex
+                fftw_irfft = x_real
                 @test AbstractFFTs.irfft(ry, size(x, first(dims)), dims) ≈ fftw_irfft
-                for P in [plan_irfft(ry, size(x, first(dims)), dims), inv(plan_rfft(x_real, dims)), 
-                          AbstractFFTs.plan_inv(plan_rfft(x_real, dims))]
+                for P in [plan_irfft(similar(ry), size(x, first(dims)), dims), inv(plan_rfft(similar(x_real), dims)), 
+                          AbstractFFTs.plan_inv(plan_rfft(similar(x_real), dims))]
                     @test P * ry ≈ fftw_irfft
-                    @test mul!(similar(x_real), P, ry) ≈ fftw_irfft
+                    @test mul!(similar(x_real), P, copy(ry)) ≈ fftw_irfft
                     @test P \ (P * ry) ≈ ry
                     @test fftdims(P) == dims
                 end