All Products
Search
Document Center

Platform For AI:Image metric learning training (raw)

Last Updated:Mar 11, 2026

Trains image metric learning models using raw data with mainstream backbones such as ResNet and Vision Transformers.

Prerequisites

OSS is activated, and Machine Learning Studio is authorized to access OSS. For more information, see Activate OSS and Grant permissions.

Limitations

Requires DLC computing engine.

Supported models

Supported backbones: resnet50, resnet18, resnet34, resnet101, swint_tiny, swint_small, swint_base, vit_tiny, vit_small, vit_base, xcit_tiny, xcit_small, and xcit_base.

Configuration

  • Input ports

    Port (left to right)

    Data type

    Recommended upstream component

    Required

    Training annotation file

    OSS

    Read OSS Data

    No

    Evaluation annotation file

    OSS

    Read OSS Data

    No

  • Parameters

    Tab

    Parameter

    Required

    Description

    Default value

    Field Settings

    Metric learning model type

    Yes

    Algorithm type for training. Valid values:

    • Data-parallel metric learning

    • Model-parallel metric learning

    Data-parallel metric learning

    OSS directory for training output

    Yes

    OSS directory where trained models are stored. Example: oss://examplebucket/yun****/designer_test

    None

    Training annotation file path

    No

    Configure if no training annotation file is connected to the input port.

    Note

    If configured in both places, input port takes precedence.

    OSS path where the training annotation file is stored. Example: oss://examplebucket/yourfolder****/data/imagenet/meta/train_labeled.txt

    Each line in train_labeled.txt must follow this format: absolute path/image_name.jpg label_id

    Important

    Separate image path and label_id with a space.

    None

    Validation annotation file path

    No

    Configure if no evaluation annotation file is connected to the input port.

    Note

    If configured in both places, input port takes precedence.

    OSS path where the validation annotation file is stored. Example: oss://examplebucket/yourfolder****/data/imagenet/meta/val_labeled.txt

    Each line in val_labeled.txt must follow this format: absolute path/image_name.jpg label_id

    Important

    Separate image path and label_id with a space.

    None

    File of class name list

    No

    Enter class names directly or specify OSS path to a file containing class names.

    None

    Data source format

    Yes

    Input data format. Valid values: ClsSourceImageList and ClsSourceItag.

    ClsSourceImageList

    OSS path of the pre-trained model

    No

    OSS path to a custom pre-trained model. If not set, PAI uses the default pre-trained model.

    None

    Parameter Settings

    Metric learning backbone

    Yes

    Backbone model for metric learning. Valid values:

    • resnet_50

    • resnet_18

    • resnet_34

    • resnet_101

    • swin_transformer_tiny

    • swin_transformer_small

    • swin_transformer_base

    resnet50

    Image resize size

    Yes

    Image size in pixels after resizing.

    224

    Backbone output feature dimension

    Yes

    Output feature dimension of the backbone. Must be an integer.

    2048

    Feature output dimension

    Yes

    Output feature dimension of the Neck. Must be an integer.

    1536

    Number of training classes

    Yes

    Number of output dimensions for metric learning.

    None

    Loss function

    Yes

    Loss function that evaluates the difference between predicted and actual values. Valid values:

    • AMSoftmax (recommended parameters: margin 0.4, scale 30)

    • ArcFaceLoss (recommended parameters: margin 28.6, scale 64)

    • CosFaceLoss (recommended parameters: margin 0.35, scale 64)

    • LargeMarginSoftmaxLoss (recommended parameters: margin 4, scale 1)

    • SphereFaceLoss (recommended parameters: margin 4, scale 1)

    • Model-parallel AMSoftmax, whose classification limit can be extended with the number of GPUs

    • Model-parallel Softmax, whose classification limit can be extended with the number of GPUs

    AMSoftmax (recommended parameters: margin 0.4, scale 30)

    Loss function scale parameter

    Yes

    Set based on the selected loss function.

    30

    Loss function margin parameter

    Yes

    Set based on the selected loss function.

    0.4

    Loss function weight

    No

    Loss function weight. Balances optimization between metric and classification.

    1.0

    Optimizer

    Yes

    Optimizer for training. Valid values:

    • SGD

    • AdamW

    SGD

    Initial learning rate

    Yes

    Initial learning rate for training. Must be a floating-point number.

    0.03

    Training batch_size

    Yes

    Number of samples trained per iteration.

    None

    Total training epochs

    Yes

    Total number of training rounds on all samples.

    200

    Checkpoint saving frequency

    No

    Frequency to save model checkpoints. A value of 1 saves after each epoch.

    10

    Execution Tuning

    Training data read threads

    No

    Number of processes for reading training data.

    4

    Enable half-precision

    No

    Enables half-precision for training to reduce memory usage.

    None

    Computing mode

    Yes

    Computing engine to run this component. Supported engines:

    • Standalone DLC

    • Distributed DLC

    Standalone DLC

    Workers

    No

    Configure when using Distributed DLC.

    Number of concurrent worker processes during training.

    1

    GPU model

    Yes

    GPU specification for training.

    8vCPU+60GB Mem+1xp100-ecs.gn5-c8g1.2xlarge

Example

Build a workflow using the Image Metric Learning Training (raw) component as shown below.WorkflowConfigure components as follows:

  1. Prepare and annotate data using the PAI iTAG module. See iTAG.

  2. Use Read OSS Data-4 and Read OSS Data-5 to read training and validation annotation files. Set OSS Data Path for each component to the corresponding annotation file path.

  3. Connect both Read OSS Data components to Image Metric Learning Training (raw) and configure parameters. See Configuration.