diff --git a/code/spectral_damage.f90 b/code/spectral_damage.f90
index 3803d482e..adbab4f16 100644
--- a/code/spectral_damage.f90
+++ b/code/spectral_damage.f90
@@ -283,10 +283,10 @@ subroutine spectral_damage_formResidual(in,x_scal,f_scal,dummy,ierr)
  DMDALocalInfo, dimension(DMDA_LOCAL_INFO_SIZE) :: &
    in
  PetscScalar, dimension( &
-   XG_RANGE,YG_RANGE,ZG_RANGE) :: &
+   XG_RANGE,YG_RANGE,ZG_RANGE), intent(in) :: &
    x_scal
  PetscScalar, dimension( &
-   X_RANGE,Y_RANGE,Z_RANGE) :: &
+   X_RANGE,Y_RANGE,Z_RANGE), intent(out) :: &
    f_scal
  PetscObject :: dummy
  PetscErrorCode :: ierr
diff --git a/code/spectral_mech_AL.f90 b/code/spectral_mech_AL.f90
index f74d76ead..ebbe212be 100644
--- a/code/spectral_mech_AL.f90
+++ b/code/spectral_mech_AL.f90
@@ -368,10 +368,10 @@ subroutine AL_formResidual(in,x_scal,f_scal,dummy,ierr)
    DMDA_LOCAL_INFO_SIZE) :: &
    in
  PetscScalar, target, dimension(3,3,2, &
-   XG_RANGE,YG_RANGE,ZG_RANGE) :: &
+   XG_RANGE,YG_RANGE,ZG_RANGE), intent(in) :: &
    x_scal
  PetscScalar, target, dimension(3,3,2, &
-   X_RANGE,Y_RANGE,Z_RANGE) :: &
+   X_RANGE,Y_RANGE,Z_RANGE), intent(out) :: &
    f_scal
  PetscScalar, pointer, dimension(:,:,:,:,:) :: &
    F, &
diff --git a/code/spectral_mech_Basic.f90 b/code/spectral_mech_Basic.f90
index 7b8c7996f..8d3e18263 100644
--- a/code/spectral_mech_Basic.f90
+++ b/code/spectral_mech_Basic.f90
@@ -330,10 +330,10 @@ subroutine BasicPETSC_formResidual(in,x_scal,f_scal,dummy,ierr)
  DMDALocalInfo, dimension(DMDA_LOCAL_INFO_SIZE) :: &
    in
  PetscScalar, dimension(3,3, &
-   XG_RANGE,YG_RANGE,ZG_RANGE) :: &
+   XG_RANGE,YG_RANGE,ZG_RANGE), intent(in) :: &
    x_scal
  PetscScalar, dimension(3,3, &
-   X_RANGE,Y_RANGE,Z_RANGE) :: &
+   X_RANGE,Y_RANGE,Z_RANGE), intent(out) :: &
    f_scal
  PetscInt :: &
    PETScIter, &
diff --git a/code/spectral_mech_Polarisation.f90 b/code/spectral_mech_Polarisation.f90
index 2c309bc69..882d13c75 100644
--- a/code/spectral_mech_Polarisation.f90
+++ b/code/spectral_mech_Polarisation.f90
@@ -368,10 +368,10 @@ subroutine Polarisation_formResidual(in,x_scal,f_scal,dummy,ierr)
    DMDA_LOCAL_INFO_SIZE) :: &
    in
  PetscScalar, target, dimension(3,3,2, &
-   XG_RANGE,YG_RANGE,ZG_RANGE) :: &
+   XG_RANGE,YG_RANGE,ZG_RANGE), intent(in) :: &
    x_scal
  PetscScalar, target, dimension(3,3,2, &
-   X_RANGE,Y_RANGE,Z_RANGE) :: &
+   X_RANGE,Y_RANGE,Z_RANGE), intent(out) :: &
    f_scal
  PetscScalar, pointer, dimension(:,:,:,:,:) :: &
    F, &
diff --git a/code/spectral_thermal.f90 b/code/spectral_thermal.f90
index e440fcf26..a3e02dfe1 100644
--- a/code/spectral_thermal.f90
+++ b/code/spectral_thermal.f90
@@ -283,10 +283,10 @@ subroutine spectral_thermal_formResidual(in,x_scal,f_scal,dummy,ierr)
  DMDALocalInfo, dimension(DMDA_LOCAL_INFO_SIZE) :: &
    in
  PetscScalar, dimension( &
-   XG_RANGE,YG_RANGE,ZG_RANGE) :: &
+   XG_RANGE,YG_RANGE,ZG_RANGE), intent(in) :: &
    x_scal
  PetscScalar, dimension( &
-   X_RANGE,Y_RANGE,Z_RANGE) :: &
+   X_RANGE,Y_RANGE,Z_RANGE), intent(out) :: &
    f_scal
  PetscObject :: dummy
  PetscErrorCode :: ierr