Intrinsic pack replaced by pointers in get_params and `get_gradie…

…nts` (#183)

* Replace intrinsic pack by pointers

* Dense layer: remove an avoidable reshape

* conv2d: avoid intrinsics pack and reshape

* replace a reshape by a pointer

* clean conv2d_layer_submodule

---------

Co-authored-by: Vandenplas, Jeremie <jeremie.vandenplas@wur.nl>
Co-authored-by: milancurcic <caomaco@gmail.com>

src/nf/nf_conv2d_layer.f90

@@ -89,19 +89,19 @@ pure module function get_num_params(self) result(num_params)
         !! Number of parameters
     end function get_num_params
 
-    pure module function get_params(self) result(params)
+    module function get_params(self) result(params)
       !! Return the parameters (weights and biases) of this layer.
       !! The parameters are ordered as weights first, biases second.
-      class(conv2d_layer), intent(in) :: self
+      class(conv2d_layer), intent(in), target :: self
         !! A `conv2d_layer` instance
       real, allocatable :: params(:)
         !! Parameters to get
     end function get_params
 
-    pure module function get_gradients(self) result(gradients)
+    module function get_gradients(self) result(gradients)
       !! Return the gradients of this layer.
       !! The gradients are ordered as weights first, biases second.
-      class(conv2d_layer), intent(in) :: self
+      class(conv2d_layer), intent(in), target :: self
         !! A `conv2d_layer` instance
       real, allocatable :: gradients(:)
         !! Gradients to get

src/nf/nf_conv2d_layer_submodule.f90

@@ -189,24 +189,32 @@ pure module function get_num_params(self) result(num_params)
   end function get_num_params
 
 
-  pure module function get_params(self) result(params)
-    class(conv2d_layer), intent(in) :: self
+  module function get_params(self) result(params)
+    class(conv2d_layer), intent(in), target :: self
     real, allocatable :: params(:)
 
+    real, pointer :: w_(:) => null()
+
+    w_(1:size(self % kernel)) => self % kernel
+
     params = [ &
-      pack(self % kernel, .true.), &
+      w_, &
       self % biases &
     ]
 
   end function get_params
 
 
-  pure module function get_gradients(self) result(gradients)
-    class(conv2d_layer), intent(in) :: self
+  module function get_gradients(self) result(gradients)
+    class(conv2d_layer), intent(in), target :: self
     real, allocatable :: gradients(:)
 
+    real, pointer :: dw_(:) => null()
+
+    dw_(1:size(self % dw)) => self % dw
+
     gradients = [ &
-      pack(self % dw, .true.), &
+      dw_, &
       self % db &
     ]
 
@@ -219,7 +227,7 @@ module subroutine set_params(self, params)
 
     ! Check that the number of parameters is correct.
     if (size(params) /= self % get_num_params()) then
-       error stop 'conv2d % set_params: Number of parameters does not match'
+      error stop 'conv2d % set_params: Number of parameters does not match'
     end if
 
     ! Reshape the kernel.
@@ -229,10 +237,9 @@ module subroutine set_params(self, params)
     )
 
     ! Reshape the biases.
-    self % biases = reshape( &
-      params(product(shape(self % kernel)) + 1:), &
-      [self % filters] &
-    )
+    associate(n => product(shape(self % kernel)))
+      self % biases = params(n + 1 : n + self % filters)
+    end associate
 
   end subroutine set_params
 

src/nf/nf_dense_layer.f90

@@ -87,19 +87,19 @@ pure module function get_num_params(self) result(num_params)
          !! Number of parameters in this layer
     end function get_num_params
 
-    pure module function get_params(self) result(params)
+    module function get_params(self) result(params)
       !! Return the parameters (weights and biases) of this layer.
       !! The parameters are ordered as weights first, biases second.
-      class(dense_layer), intent(in) :: self
+      class(dense_layer), intent(in), target :: self
         !! Dense layer instance
       real, allocatable :: params(:)
         !! Parameters of this layer
     end function get_params
 
-    pure module function get_gradients(self) result(gradients)
+    module function get_gradients(self) result(gradients)
       !! Return the gradients of this layer.
       !! The gradients are ordered as weights first, biases second.
-      class(dense_layer), intent(in) :: self
+      class(dense_layer), intent(in), target :: self
         !! Dense layer instance
       real, allocatable :: gradients(:)
         !! Gradients of this layer
@@ -110,7 +110,7 @@ module subroutine set_params(self, params)
       !! The parameters are ordered as weights first, biases second.
       class(dense_layer), intent(in out) :: self
         !! Dense layer instance
-      real, intent(in) :: params(:)
+      real, intent(in), target :: params(:)
         !! Parameters of this layer
     end subroutine set_params
 

src/nf/nf_dense_layer_submodule.f90

@@ -61,24 +61,32 @@ pure module function get_num_params(self) result(num_params)
   end function get_num_params
 
 
-  pure module function get_params(self) result(params)
-    class(dense_layer), intent(in) :: self
+  module function get_params(self) result(params)
+    class(dense_layer), intent(in), target :: self
     real, allocatable :: params(:)
 
+    real, pointer :: w_(:) => null()
+
+    w_(1:size(self % weights)) => self % weights
+
     params = [ &
-      pack(self % weights, .true.), &
+      w_, &
       self % biases &
     ]
 
   end function get_params
 
 
-  pure module function get_gradients(self) result(gradients)
-    class(dense_layer), intent(in) :: self
+  module function get_gradients(self) result(gradients)
+    class(dense_layer), intent(in), target :: self
     real, allocatable :: gradients(:)
 
+    real, pointer :: dw_(:) => null()
+
+    dw_(1:size(self % dw)) => self % dw
+
     gradients = [ &
-      pack(self % dw, .true.), &
+      dw_, &
       self % db &
     ]
 
@@ -87,24 +95,23 @@ end function get_gradients
 
   module subroutine set_params(self, params)
     class(dense_layer), intent(in out) :: self
-    real, intent(in) :: params(:)
+    real, intent(in), target :: params(:)
+
+    real, pointer :: p_(:,:) => null()
 
     ! check if the number of parameters is correct
     if (size(params) /= self % get_num_params()) then
       error stop 'Error: number of parameters does not match'
     end if
 
-    ! reshape the weights
-    self % weights = reshape( &
-      params(:self % input_size * self % output_size), &
-      [self % input_size, self % output_size] &
-    )
-
-    ! reshape the biases
-    self % biases = reshape( &
-      params(self % input_size * self % output_size + 1:), &
-      [self % output_size] &
-    )
+    associate(n => self % input_size * self % output_size)
+      ! reshape the weights
+      p_(1:self % input_size, 1:self % output_size) => params(1 : n)
+      self % weights = p_
+
+      ! reshape the biases
+      self % biases = params(n + 1 : n + self % output_size)
+    end associate
 
   end subroutine set_params
 

src/nf/nf_layer.f90

@@ -129,15 +129,15 @@ elemental module function get_num_params(self) result(num_params)
         !! Number of parameters in this layer
     end function get_num_params
 
-    pure module function get_params(self) result(params)
+    module function get_params(self) result(params)
       !! Returns the parameters of this layer.
       class(layer), intent(in) :: self
         !! Layer instance
       real, allocatable :: params(:)
         !! Parameters of this layer
     end function get_params
 
-    pure module function get_gradients(self) result(gradients)
+    module function get_gradients(self) result(gradients)
       !! Returns the gradients of this layer.
       class(layer), intent(in) :: self
         !! Layer instance

src/nf/nf_layer_submodule.f90

@@ -298,7 +298,7 @@ elemental module function get_num_params(self) result(num_params)
 
   end function get_num_params
 
-  pure module function get_params(self) result(params)
+  module function get_params(self) result(params)
     class(layer), intent(in) :: self
     real, allocatable :: params(:)
 
@@ -323,7 +323,7 @@ pure module function get_params(self) result(params)
 
   end function get_params
 
-  pure module function get_gradients(self) result(gradients)
+  module function get_gradients(self) result(gradients)
     class(layer), intent(in) :: self
     real, allocatable :: gradients(:)
 

src/nf/nf_network.f90

@@ -172,15 +172,15 @@ pure module integer function get_num_params(self)
       !! Network instance
     end function get_num_params
 
-    pure module function get_params(self) result(params)
+    module function get_params(self) result(params)
       !! Get the network parameters (weights and biases).
       class(network), intent(in) :: self
         !! Network instance
       real, allocatable :: params(:)
         !! Network parameters to get
     end function get_params
 
-    pure module function get_gradients(self) result(gradients)
+    module function get_gradients(self) result(gradients)
       class(network), intent(in) :: self
         !! Network instance
       real, allocatable :: gradients(:)

src/nf/nf_network_submodule.f90

@@ -526,7 +526,7 @@ pure module function get_num_params(self)
   end function get_num_params
 
 
-  pure module function get_params(self) result(params)
+  module function get_params(self) result(params)
     class(network), intent(in) :: self
     real, allocatable :: params(:)
     integer :: n, nstart, nend
@@ -546,7 +546,7 @@ pure module function get_params(self) result(params)
   end function get_params
 
 
-  pure module function get_gradients(self) result(gradients)
+  module function get_gradients(self) result(gradients)
     class(network), intent(in) :: self
     real, allocatable :: gradients(:)
     integer :: n, nstart, nend