athena__maxpool2d_layer Module

Module containing implementation of a 2D max pooling layer

This module implements 2D max pooling for downsampling spatial dimensions by selecting maximum values within pooling windows.

Mathematical operation: output[i,j,k] = max_{m∈[0,pool_h), n∈[0,pool_w)} input[istride+m, jstride+n, k]

where: (i,j) are output spatial coordinates k is the channel index (pool_h, pool_w) is the pooling window size stride controls the step size

Reduces spatial dimensions while preserving important features. Shape: (width, height, channels) -> (width//stride, height//stride, channels)


Uses


Interfaces

public interface maxpool2d_layer_type

Interface for setting up the 2D max pooling layer

  • private module function layer_setup(input_shape, pool_size, stride, padding, verbose) result(layer)

    Set up the 2D max pooling layer

    Arguments

    Type IntentOptional Attributes Name
    integer, intent(in), optional, dimension(:) :: input_shape

    Input shape
    integer, intent(in), optional, dimension(..) :: pool_size

    Pool size
    integer, intent(in), optional, dimension(..) :: stride

    Stride
    character(len=*), intent(in), optional :: padding

    Padding
    integer, intent(in), optional :: verbose

    Verbosity level

    Return Value type(maxpool2d_layer_type)

    Instance of the 2D max pooling layer


Derived Types

type, public, extends(pool_layer_type) ::  maxpool2d_layer_type

Type for 2D max pooling layer with overloaded procedures

Components

Type Visibility Attributes Name Initial
type(graph_type), public, allocatable, dimension(:) :: graph

Graph structure of input data
integer, public :: id

Unique identifier
logical, public :: inference = .false.

Inference mode
integer, public :: input_rank = 0

Rank of input data
integer, public, allocatable, dimension(:) :: input_shape

Input shape
character(len=:), public, allocatable :: name

Layer name
integer, public :: num_channels

Number of channels
class(array_type), public, allocatable, dimension(:,:) :: output

Output
integer, public :: output_rank = 0

Rank of output data
integer, public, allocatable, dimension(:) :: output_shape

Output shape
class(pad_layer_type), public, allocatable :: pad_layer

Padding layer
integer, public, allocatable, dimension(:) :: pool

Pooling and stride sizes
integer, public, allocatable, dimension(:) :: strd

Pooling and stride sizes
character(len=20), public :: subtype = repeat(" ", 20)
character(len=4), public :: type = 'base'

Layer type
logical, public :: use_graph_input = .false.

Use graph input
logical, public :: use_graph_output = .false.

Use graph output

Constructor

Interface for setting up the 2D max pooling layer

private module function layer_setup (input_shape, pool_size, stride, padding, verbose)

Set up the 2D max pooling layer

Type-Bound Procedures

procedure, public, pass(this) :: build_from_onnx => build_from_onnx_maxpool2d

Build 2D max pooling layer from ONNX node and initialiser
procedure, public, pass(this) :: emit_onnx_graph_inputs => emit_onnx_graph_inputs_base

Emit graph input tensor declarations for this layer
procedure, public, pass(this) :: emit_onnx_nodes => emit_onnx_nodes_base

Emit ONNX JSON nodes for this layer (format-aware and polymorphic)
procedure, public, pass(this) :: extract_output => extract_output_base

Extract the output of the layer as a standard real array
procedure, public, pass(this) :: forward => forward_maxpool2d

Forward propagation derived type handler
procedure, public, pass(this) :: forward_eval => forward_eval_base

Forward pass of layer and return output for evaluation
procedure, public, pass(this) :: get_attributes => get_attributes_pool

Get the attributes of the layer (for ONNX export)
procedure, public, pass(this) :: get_num_params => get_num_params_base

Get the number of parameters in the layer
procedure, public, pass(this) :: init => init_pool

Initialise the layer
procedure, public, pass(this) :: nullify_graph => nullify_graph_base

Nullify the forward pass data of the layer to free memory

Read more…
procedure, public, pass(this) :: print => print_base

Print the layer to a file with additional information
procedure, public, pass(this) :: print_to_unit => print_to_unit_pool

Print layer to unit
procedure, public, pass(this) :: read => read_maxpool2d

Read 2D max pooling layer from file
procedure, public, pass(this) :: set_graph => set_graph_base

Set the graph structure of the input data !! this is adjacency and edge weighting
procedure, public, pass(this) :: set_hyperparams => set_hyperparams_maxpool2d

Set hyperparameters for 2D max pooling layer
procedure, public, pass(this) :: set_rank => set_rank_base

Set the input and output ranks of the layer
procedure, public, pass(this) :: set_shape => set_shape_base

Set the input shape of the layer

Functions

public function read_maxpool2d_layer(unit, verbose) result(layer)

Read 2D max pooling layer from file and return layer

Arguments

Type IntentOptional Attributes Name
integer, intent(in) :: unit

File unit
integer, intent(in), optional :: verbose

Verbosity level

Return Value class(base_layer_type), allocatable

Instance of the 2D max pooling layer

private module function layer_setup(input_shape, pool_size, stride, padding, verbose) result(layer)

!############################################################################# set up layer ! set up layer

Read more…

Arguments

Type IntentOptional Attributes Name
integer, intent(in), optional, dimension(:) :: input_shape

Input shape
integer, intent(in), optional, dimension(..) :: pool_size

Pool size
integer, intent(in), optional, dimension(..) :: stride

Stride
character(len=*), intent(in), optional :: padding

Padding
integer, intent(in), optional :: verbose

Verbosity level

Return Value type(maxpool2d_layer_type)

Instance of the 2D max pooling layer


Subroutines

private subroutine build_from_onnx_maxpool2d(this, node, initialisers, value_info, verbose)

Read ONNX attributes for 2D max pooling layer

Arguments

Type IntentOptional Attributes Name
class(maxpool2d_layer_type), intent(inout) :: this

Instance of the 2D max pooling layer
type(onnx_node_type), intent(in) :: node

ONNX node information
type(onnx_initialiser_type), intent(in), dimension(:) :: initialisers

ONNX initialiser information
type(onnx_tensor_type), intent(in), dimension(:) :: value_info

ONNX value info
integer, intent(in) :: verbose

Verbosity level

private subroutine forward_maxpool2d(this, input)

Forward propagation

Arguments

Type IntentOptional Attributes Name
class(maxpool2d_layer_type), intent(inout) :: this

Instance of the 2D max pooling layer
class(array_type), intent(in), dimension(:,:) :: input

Input values

private subroutine read_maxpool2d(this, unit, verbose)

Read 2D max pooling layer from file

Arguments

Type IntentOptional Attributes Name
class(maxpool2d_layer_type), intent(inout) :: this

Instance of the 2D max pooling layer
integer, intent(in) :: unit

File unit
integer, intent(in), optional :: verbose

Verbosity level

private subroutine set_hyperparams_maxpool2d(this, pool_size, stride, padding, verbose)

Set hyperparameters for 2D max pooling layer

Arguments

Type IntentOptional Attributes Name
class(maxpool2d_layer_type), intent(inout) :: this

Instance of the 2D max pooling layer
integer, intent(in), dimension(2) :: pool_size

Pool size
integer, intent(in), dimension(2) :: stride

Stride
character(len=*), intent(in), optional :: padding

Padding
integer, intent(in), optional :: verbose

Verbosity level