Merge pull request #31 from cval26/fftshift

Remove dynamic memory allocations in shift procedures

Author: zoziha

src/fftpack.f90

@@ -18,7 +18,7 @@ module fftpack
 
     public :: dcosti, dcost
     public :: dct, idct
-    
+
     public :: rk
 
     interface
@@ -276,11 +276,11 @@ end function dct_rk
     interface fftshift
         pure module function fftshift_crk(x) result(result)
             complex(kind=rk), intent(in) :: x(:)
-            complex(kind=rk), allocatable :: result(:)
+            complex(kind=rk), dimension(size(x)) :: result
         end function fftshift_crk
         pure module function fftshift_rrk(x) result(result)
             real(kind=rk), intent(in) :: x(:)
-            real(kind=rk), allocatable :: result(:)
+            real(kind=rk), dimension(size(x)) :: result
         end function fftshift_rrk
     end interface fftshift
 
@@ -291,11 +291,11 @@ end function fftshift_rrk
     interface ifftshift
         pure module function ifftshift_crk(x) result(result)
             complex(kind=rk), intent(in) :: x(:)
-            complex(kind=rk), allocatable :: result(:)
+            complex(kind=rk), dimension(size(x)) :: result
         end function ifftshift_crk
         pure module function ifftshift_rrk(x) result(result)
             real(kind=rk), intent(in) :: x(:)
-            real(kind=rk), allocatable :: result(:)
+            real(kind=rk), dimension(size(x)) :: result
         end function ifftshift_rrk
     end interface ifftshift
 

src/fftpack_fftshift.f90

@@ -5,7 +5,7 @@
     !> Shifts zero-frequency component to center of spectrum for `complex` type.
     pure module function fftshift_crk(x) result(result)
         complex(kind=rk), intent(in) :: x(:)
-        complex(kind=rk), allocatable :: result(:)
+        complex(kind=rk), dimension(size(x)) :: result
 
         result = cshift(x, shift=-floor(0.5_rk*size(x)))
 
@@ -14,7 +14,7 @@ end function fftshift_crk
     !> Shifts zero-frequency component to center of spectrum for `real` type.
     pure module function fftshift_rrk(x) result(result)
         real(kind=rk), intent(in) :: x(:)
-        real(kind=rk), allocatable :: result(:)
+        real(kind=rk), dimension(size(x)) :: result
 
         result = cshift(x, shift=-floor(0.5_rk*size(x)))
 

src/fftpack_ifftshift.f90

@@ -5,7 +5,7 @@
     !> Shifts zero-frequency component to beginning of spectrum for `complex` type.
     pure module function ifftshift_crk(x) result(result)
         complex(kind=rk), intent(in) :: x(:)
-        complex(kind=rk), allocatable :: result(:)
+        complex(kind=rk), dimension(size(x)) :: result
 
         result = cshift(x, shift=-ceiling(0.5_rk*size(x)))
 
@@ -14,7 +14,7 @@ end function ifftshift_crk
     !> Shifts zero-frequency component to beginning of spectrum for `real` type.
     pure module function ifftshift_rrk(x) result(result)
         real(kind=rk), intent(in) :: x(:)
-        real(kind=rk), allocatable :: result(:)
+        real(kind=rk), dimension(size(x)) :: result
 
         result = cshift(x, shift=-ceiling(0.5_rk*size(x)))