Fix conv1d with stride

Author: jvdp1

src/nf/nf_conv1d_layer.f90

@@ -63,7 +63,7 @@ module subroutine init(self, input_shape)
           !! Input layer dimensions
       end subroutine init
 
-      pure module subroutine forward(self, input)
+      module subroutine forward(self, input)
         !! Apply a forward pass on the `conv1d` layer.
         class(conv1d_layer), intent(in out) :: self
           !! A `conv1d_layer` instance

src/nf/nf_conv1d_layer_submodule.f90

@@ -27,7 +27,9 @@ module subroutine init(self, input_shape)
     integer, intent(in) :: input_shape(:)
 
     self % channels = input_shape(1)
-    self % width = (input_shape(2) - self % kernel_size + 1) / self % stride
+    self % width = (input_shape(2) - self % kernel_size) / self % stride +1
+
+    if (mod(input_shape(2) - self % kernel_size , self % stride) /= 0) self % width = self % width + 1
 
     ! Output of shape: filters x width
     allocate(self % output(self % filters, self % width))
@@ -55,7 +57,7 @@ module subroutine init(self, input_shape)
 
   end subroutine init
 
-  pure module subroutine forward(self, input)
+  module subroutine forward(self, input)
     implicit none
     class(conv1d_layer), intent(in out) :: self
     real, intent(in) :: input(:,:)
@@ -71,7 +73,7 @@ pure module subroutine forward(self, input)
       ! Compute the input window corresponding to output index j.
       ! In forward: center index = j + half_window, so window = indices j to j+kernel_size-1.
       iws = self % stride * (j-1) + 1
-      iwe = max(iws + self % kernel_size - 1, input_width)
+      iwe = min(iws + self % kernel_size - 1, input_width)
 
       ! For each filter, compute the convolution (inner product over channels and kernel width).
       do concurrent (n = 1:self % filters)

src/nf/nf_layer_constructors_submodule.f90

@@ -33,9 +33,6 @@ module function conv1d(filters, kernel_width, activation, stride) result(res)
     integer :: stride_tmp
     class(activation_function), allocatable :: activation_tmp
 
-    if (stride < 1) &
-      error stop 'stride must be >= 1 in a conv1d layer'
-
     res % name = 'conv1d'
 
     if (present(activation)) then
@@ -52,6 +49,9 @@ module function conv1d(filters, kernel_width, activation, stride) result(res)
       stride_tmp = 1
     endif
 
+    if (stride_tmp < 1) &
+      error stop 'stride must be >= 1 in a conv1d layer'
+
     allocate( &
       res % p, &
       source=conv1d_layer(filters, kernel_width, activation_tmp, stride_tmp) &

test/test_conv1d_layer.f90

@@ -58,6 +58,7 @@ program test_conv1d_layer
     select type(this_layer => input_layer % p); type is(input2d_layer)
       call this_layer % set(sample_input)
     end select
+    deallocate(sample_input)
 
     call conv1d_layer % forward(input_layer)
     call conv1d_layer % get_output(output)
@@ -67,11 +68,33 @@ program test_conv1d_layer
       write(stderr, '(a)') 'conv1d layer with zero input and sigmoid function must forward to all 0.5.. failed'
     end if
 
+    ! Minimal conv1d layer: 1 channel, 3x3 pixel image, stride = 3;
+    allocate(sample_input(1, 17))
+    sample_input = 0
+  
+    input_layer = input(1, 17)
+    conv1d_layer = conv(filters, kernel_size, stride = 3)
+    call conv1d_layer % init(input_layer)
+  
+    select type(this_layer => input_layer % p); type is(input2d_layer)
+      call this_layer % set(sample_input)
+    end select
+    deallocate(sample_input)
+  
+    call conv1d_layer % forward(input_layer)
+    call conv1d_layer % get_output(output)
+  
+    if (.not. all(abs(output) < tolerance)) then
+      ok = .false.
+      write(stderr, '(a)') 'conv1d layer with zero input and sigmoid function must forward to all 0.5.. failed'
+    end if
+  
+    !Final
     if (ok) then
       print '(a)', 'test_conv1d_layer: All tests passed.'
     else
       write(stderr, '(a)') 'test_conv1d_layer: One or more tests failed.'
-      stop 1
+      stop 2
     end if
-  
+
 end program test_conv1d_layer