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