| Line | Branch | Exec | Source |
|---|---|---|---|
| 1 | module athena__activation_tanh | ||
| 2 | !! Module containing implementation of the tanh activation function | ||
| 3 | !! | ||
| 4 | !! This module implements the hyperbolic tangent activation that squashes | ||
| 5 | !! inputs to the range (-1, 1), zero-centered unlike sigmoid. | ||
| 6 | !! | ||
| 7 | !! Mathematical operation: | ||
| 8 | !! \[ \tanh(x) = \frac{e^x - e^{-x}}{e^x + e^{-x}} = \frac{e^{2x} - 1}{e^{2x} + 1} \] | ||
| 9 | !! | ||
| 10 | !! Derivative: | ||
| 11 | !! \[ \tanh'(x) = 1 - \tanh^2(x) \] | ||
| 12 | !! | ||
| 13 | !! Properties: Smooth, bounded \([-1,1]\), zero-centered, saturates for large \(|x|\) | ||
| 14 | !! Preferred over sigmoid in many cases due to zero-centering | ||
| 15 | use coreutils, only: real32, print_warning | ||
| 16 | use diffstruc, only: array_type, operator(*), tanh | ||
| 17 | use athena__misc_types, only: base_actv_type | ||
| 18 | use athena__misc_types, only: onnx_attribute_type | ||
| 19 | implicit none | ||
| 20 | |||
| 21 | |||
| 22 | private | ||
| 23 | |||
| 24 | public :: tanh_actv_type, create_from_onnx_tanh_activation | ||
| 25 | |||
| 26 | |||
| 27 | type, extends(base_actv_type) :: tanh_actv_type | ||
| 28 | !! Type for tanh activation function with overloaded procedures | ||
| 29 | contains | ||
| 30 | procedure, pass(this) :: apply => apply_tanh | ||
| 31 | procedure, pass(this) :: reset => reset_tanh | ||
| 32 | procedure, pass(this) :: apply_attributes => apply_attributes_tanh | ||
| 33 | procedure, pass(this) :: export_attributes => export_attributes_tanh | ||
| 34 | end type tanh_actv_type | ||
| 35 | |||
| 36 | interface tanh_actv_type | ||
| 37 | procedure initialise | ||
| 38 | end interface tanh_actv_type | ||
| 39 | |||
| 40 | |||
| 41 | |||
| 42 | contains | ||
| 43 | |||
| 44 | !############################################################################### | ||
| 45 | − | function initialise(scale, attributes) result(activation) | |
| 46 | !! Initialise a tanh activation function | ||
| 47 | implicit none | ||
| 48 | |||
| 49 | ! Arguments | ||
| 50 | real(real32), intent(in), optional :: scale | ||
| 51 | !! Optional scale factor for activation output | ||
| 52 | type(onnx_attribute_type), dimension(:), intent(in), optional :: attributes | ||
| 53 | !! Optional array of ONNX attributes | ||
| 54 | type(tanh_actv_type) :: activation | ||
| 55 | !! tanh activation type | ||
| 56 | |||
| 57 | |||
| 58 | − | call activation%reset() | |
| 59 | |||
| 60 | − | if(present(scale)) activation%scale = scale | |
| 61 | − | if(abs(activation%scale-1._real32) .gt. 1.e-6_real32)then | |
| 62 | − | activation%apply_scaling = .true. | |
| 63 | end if | ||
| 64 | |||
| 65 | − | if(present(attributes)) then | |
| 66 | − | call activation%apply_attributes(attributes) | |
| 67 | end if | ||
| 68 | |||
| 69 | − | end function initialise | |
| 70 | !------------------------------------------------------------------------------- | ||
| 71 | − | pure subroutine reset_tanh(this) | |
| 72 | !! Reset tanh activation function attributes and variables | ||
| 73 | implicit none | ||
| 74 | |||
| 75 | ! Arguments | ||
| 76 | class(tanh_actv_type), intent(inout) :: this | ||
| 77 | !! Tanh activation type | ||
| 78 | |||
| 79 | − | this%name = "tanh" | |
| 80 | − | this%scale = 1._real32 | |
| 81 | − | this%threshold = 0._real32 | |
| 82 | − | this%apply_scaling = .false. | |
| 83 | |||
| 84 | − | end subroutine reset_tanh | |
| 85 | !------------------------------------------------------------------------------- | ||
| 86 | − | function create_from_onnx_tanh_activation(attributes) result(activation) | |
| 87 | !! Create tanh activation function from ONNX attributes | ||
| 88 | implicit none | ||
| 89 | |||
| 90 | ! Arguments | ||
| 91 | type(onnx_attribute_type), dimension(:), intent(in) :: attributes | ||
| 92 | !! Array of ONNX attributes | ||
| 93 | |||
| 94 | class(base_actv_type), allocatable :: activation | ||
| 95 | !! Instance of activation type | ||
| 96 | |||
| 97 | − | allocate(activation, source = tanh_actv_type(attributes = attributes)) | |
| 98 | |||
| 99 | − | end function create_from_onnx_tanh_activation | |
| 100 | !############################################################################### | ||
| 101 | |||
| 102 | |||
| 103 | !############################################################################### | ||
| 104 | − | subroutine apply_attributes_tanh(this, attributes) | |
| 105 | !! Load ONNX attributes into tanh activation function | ||
| 106 | implicit none | ||
| 107 | |||
| 108 | ! Arguments | ||
| 109 | class(tanh_actv_type), intent(inout) :: this | ||
| 110 | !! Tanh activation type | ||
| 111 | type(onnx_attribute_type), dimension(:), intent(in) :: attributes | ||
| 112 | !! Array of ONNX attributes | ||
| 113 | |||
| 114 | ! Local variables | ||
| 115 | integer :: i | ||
| 116 | !! Loop variable | ||
| 117 | |||
| 118 | ! Load provided attributes | ||
| 119 | − | do i=1, size(attributes,dim=1) | |
| 120 | − | select case(trim(attributes(i)%name)) | |
| 121 | case("scale") | ||
| 122 | − | read(attributes(i)%val,*) this%scale | |
| 123 | − | if(abs(this%scale-1._real32) .gt. 1.e-6_real32)then | |
| 124 | − | this%apply_scaling = .true. | |
| 125 | else | ||
| 126 | − | this%apply_scaling = .false. | |
| 127 | end if | ||
| 128 | case("name") | ||
| 129 | − | if(trim(attributes(i)%val) .ne. trim(this%name)) then | |
| 130 | call print_warning( & | ||
| 131 | 'Tanh activation: name attribute "' // & | ||
| 132 | − | trim(attributes(i)%val) // & | |
| 133 | '"" does not match expected "' // trim(this%name)//'"' & | ||
| 134 | − | ) | |
| 135 | |||
| 136 | end if | ||
| 137 | case default | ||
| 138 | call print_warning( & | ||
| 139 | − | 'Tanh activation: unknown attribute '//trim(attributes(i)%name) & | |
| 140 | − | ) | |
| 141 | end select | ||
| 142 | end do | ||
| 143 | |||
| 144 | − | end subroutine apply_attributes_tanh | |
| 145 | !############################################################################### | ||
| 146 | |||
| 147 | |||
| 148 | !############################################################################### | ||
| 149 | − | pure function export_attributes_tanh(this) result(attributes) | |
| 150 | !! Export tanh activation function attributes as ONNX attributes | ||
| 151 | implicit none | ||
| 152 | |||
| 153 | ! Arguments | ||
| 154 | class(tanh_actv_type), intent(in) :: this | ||
| 155 | !! Tanh activation type | ||
| 156 | type(onnx_attribute_type), allocatable, dimension(:) :: attributes | ||
| 157 | !! Array of ONNX attributes | ||
| 158 | |||
| 159 | ! Local variables | ||
| 160 | character(50) :: buffer | ||
| 161 | !! Temporary string buffer | ||
| 162 | |||
| 163 | − | allocate(attributes(2)) | |
| 164 | |||
| 165 | − | write(buffer, '(A)') this%name | |
| 166 | − | attributes(1) = onnx_attribute_type( & | |
| 167 | − | "name", "string", trim(adjustl(buffer)) ) | |
| 168 | |||
| 169 | − | write(buffer, '(F10.6)') this%scale | |
| 170 | − | attributes(2) = onnx_attribute_type( & | |
| 171 | − | "scale", "float", trim(adjustl(buffer)) ) | |
| 172 | |||
| 173 | − | end function export_attributes_tanh | |
| 174 | !############################################################################### | ||
| 175 | |||
| 176 | |||
| 177 | !############################################################################### | ||
| 178 | − | function apply_tanh(this, val) result(output) | |
| 179 | !! Apply tanh activation to 1D array | ||
| 180 | !! | ||
| 181 | !! Applies the hyperbolic tangent function element-wise to input array: | ||
| 182 | !! f = (exp(x) - exp(-x))/(exp(x) + exp(-x)) | ||
| 183 | implicit none | ||
| 184 | |||
| 185 | ! Arguments | ||
| 186 | class(tanh_actv_type), intent(in) :: this | ||
| 187 | !! Tanh activation type | ||
| 188 | type(array_type), intent(in) :: val | ||
| 189 | !! Input values | ||
| 190 | type(array_type), pointer :: output | ||
| 191 | !! Activated output values | ||
| 192 | |||
| 193 | − | if(this%apply_scaling)then | |
| 194 | − | output => tanh(val) * this%scale | |
| 195 | else | ||
| 196 | − | output => tanh(val) | |
| 197 | end if | ||
| 198 | − | end function apply_tanh | |
| 199 | !############################################################################### | ||
| 200 | |||
| 201 | − | end module athena__activation_tanh | |
| 202 |