add tests for sigmoid and gelu

Author: jalvesz

test/specialfunctions/test_specialfunctions_activations.fypp

@@ -5,7 +5,7 @@ module test_specialfunctions_activation
     use testdrive, only : new_unittest, unittest_type, error_type, check
     use stdlib_kinds
     use stdlib_specialfunctions
-
+    use stdlib_math, only: linspace
     implicit none
     private
 
@@ -21,10 +21,46 @@ contains
         type(unittest_type), allocatable, intent(out) :: testsuite(:)
 
         testsuite = [                                       &
+            new_unittest("sigmoid", test_sigmoid),          &
+            new_unittest("gelu"   , test_gelu   ),          &
             new_unittest("softmax", test_softmax)           &
             ]
     end subroutine collect_specialfunctions_activation
 
+    subroutine test_sigmoid(error)
+        type(error_type), allocatable, intent(out) :: error
+        integer, parameter :: n = 10
+        real(sp) :: x(n), y(n), y_ref(n)
+
+        y_ref = [0.119202919304371, 0.174285307526588, 0.247663781046867,&
+                 0.339243650436401, 0.444671928882599, 0.555328071117401,&
+                 0.660756349563599, 0.752336204051971, 0.825714707374573,&
+                 0.880797028541565]
+        x = linspace(-2._sp, 2._sp, n)
+        y = sigmoid( x )
+        call check(error, norm2(y-y_ref) < n*tol_sp )
+        if (allocated(error)) return
+    end subroutine
+
+    subroutine test_gelu(error)
+        type(error_type), allocatable, intent(out) :: error
+        integer, parameter :: n = 10
+        real(sp) :: x(n), y(n), y_ref(n)
+
+        y_ref = [-0.0455002784729  , -0.093188509345055, -0.148066952824593,&
+                 -0.168328359723091, -0.0915712043643  ,  0.130650997161865,&
+                  0.498338282108307,  0.963044226169586,  1.462367057800293,&
+                  1.9544997215271  ]
+        x = linspace(-2._sp, 2._sp, n)
+        y = gelu( x )
+        call check(error, norm2(y-y_ref) < n*tol_sp )
+        if (allocated(error)) return
+
+        y = gelu_approx( x )
+        call check(error, norm2(y-y_ref) < n*tol_sp )
+        if (allocated(error)) return
+    end subroutine
+
     subroutine test_softmax(error)
         type(error_type), allocatable, intent(out) :: error
 
@@ -88,7 +124,7 @@ contains
                            0.364060789, 0.241637364, 0.292525023,&
                            0.279837668, 0.357372403, 0.405537367,&
                            0.314476222, 0.404643506, 0.374830246,&
-                           
+
                            0.223737061, 0.410527140, 0.206393898,&
                            0.288762331, 0.224173695, 0.284117699,&
                            0.338987619, 0.295757085, 0.329763889 ] ,[3,3,3] )