Targeting the IPU from TensorFlow 2

• 1. Introduction
  • 1.1. Document overview
• 2. Targeting the Poplar XLA device
  • 2.1. Supported types
  • 2.2. Device selection
  • 2.3. Configuring system options
    • 2.3.1. TF_POPLAR_FLAGS environment variable
  • 2.4. Supported operations
  • 2.5. Unsupported operations
  • 2.6. Error Handling
    • 2.6.1. Construction and compilation errors
    • 2.6.2. Runtime errors
• 3. Support for TensorFlow 2
  • 3.1. IPUStrategy
  • 3.2. Execution modes
    • 3.2.1. Graph mode with @tf.function
    • 3.2.2. Eager mode
  • 3.3. On-device loops
• 4. Keras with IPUs
  • 4.1. Single IPU models
  • 4.2. Using steps_per_execution
  • 4.3. Gradient accumulation
  • 4.4. Model parallelism
    • 4.4.1. Sequential model
    • 4.4.2. Functional model
      • Pipelining a model you are writing yourself
      • Pipelining an existing functional model
  • 4.5. Automatic data parallelism
  • 4.6. Asynchronous callbacks
  • 4.7. Configuring Infeeds and Outfeed
  • 4.8. Porting models from TensorFlow 2.1
    • 4.8.1. TF2.1
    • 4.8.2. TF2.4
  • 4.9. Implementation details
• 5. Compiling and pre-compiling executables
  • 5.1. Caching of compiled executables
  • 5.2. Pre-compiling executables
    • 5.2.1. Unsupported Operations
• 6. Training a model
  • 6.1. Training loops, data sets and feed queues
  • 6.2. Accessing outfeed queue results during execution
  • 6.3. Replicated graphs
    • 6.3.1. Selecting the number of replicas
    • 6.3.2. Performing parameter updates
  • 6.4. Pipelined training
    • 6.4.1. Grouped scheduling
    • 6.4.2. Interleaved scheduling
    • 6.4.3. Sequential scheduling
    • 6.4.4. Pipeline stage inputs and outputs
    • 6.4.5. Applying an optimiser to the graph
    • 6.4.6. Device mapping
    • 6.4.7. Concurrent pipeline stages
  • 6.5. Gradient accumulation
    • 6.5.1. Optimizers
    • 6.5.2. Pipelining
    • 6.5.3. Accumulation data type
  • 6.6. Optimizer state offloading
  • 6.7. Dataset benchmarking
    • 6.7.1. Accessing the JSON data
• 7. Efficient IPU I/O
  • 7.1. Prefetch elements
  • 7.2. I/O Tiles
• 8. Example using IPUEstimator
• 9. Example using IPUPipelineEstimator
• 10. Distributed training
  • 10.1. Example using IPUMultiWorkerStrategy
    • 10.1.1. The input function
    • 10.1.2. The model function
    • 10.1.3. Cluster definition
    • 10.1.4. Complete example
  • 10.2. Distributed training with Horovod
  • 10.3. Launching Horovod training
  • 10.4. Complete Horovod example
• 11. Half-precision floating point and stochastic rounding
  • 11.1. Controlling the half-precision floating-point unit
  • 11.2. Resetting the global random number seed
  • 11.3. Debugging numerical issues
• 12. IPU-optimised operations
  • 12.1. LSTM and GRU
  • 12.2. Dropout
  • 12.3. Embedding lookup
  • 12.4. Group normalisation
  • 12.5. Instance normalisation
  • 12.6. Layer normalisation
  • 12.7. GeLU activation
  • 12.8. Sequence slice
  • 12.9. Histogram
• 13. IPU Outlined Functions
  • 13.1. Usage
  • 13.2. Examples
    • 13.2.1. Models with common structures
    • 13.2.2. Serializing large operations
• 14. Writing custom operations
  • 14.1. Custom operation on the IPU
    • 14.1.1. Building the Poplar graph
    • 14.1.2. Gradient builders
    • 14.1.3. Metadata
    • 14.1.4. Compiling the IPU code
      • API level
      • PopLibs library code
      • Compiling the library file
    • 14.1.5. Using the custom op in TensorFlow
    • 14.1.6. Tensor allocation
    • 14.1.7. Examples
      • In-place operations
      • Operation attributes
      • Custom codelet
  • 14.2. Custom host CPU operations
    • 14.2.1. Gradient callback
• 15. IPU host embeddings
  • 15.1. Usage
  • 15.2. Example
  • 15.3. Experimental functionality: IPU embeddings in remote buffers
    • 15.3.1. Partitioning strategies
      • Token strategy
      • Encoding strategy
      • Choosing a strategy for your application
• 16. IPU embedded application runtime
  • 16.1. Usage
  • 16.2. Pipelining and I/O tiles
    • 16.2.1. Parallel requests
    • 16.2.2. Timeout
    • 16.2.3. Engine restarts
  • 16.3. Example
  • 16.4. Error Handling
    • 16.4.1. Runtime errors
• 17. Retrieving information about compilation and execution
  • 17.1. TensorFlow options for reporting
  • 17.2. XLA graph file naming
• 18. IPU TensorFlow Addons
  • 18.1. Introduction
  • 18.2. Keras layers
  • 18.3. Optimizers
• 19. API changes
  • 19.1. Release 2.4
    • 19.1.1. Breaking changes
      • Summary ops
      • Removal of deprecated members
    • 19.1.2. Non-breaking changes
  • 19.2. Release 2.3
    • 19.2.1. Breaking changes
      • Custom user op metadata interface updates
      • The verified transfers feature has been removed
    • 19.2.2. Non-breaking changes
  • 19.3. Release 2.2
    • 19.3.1. Breaking changes
      • C++ Poplar TensorFlow libraries are private by default
      • Reports removed from ipu events
      • TensorFlow 2.1 to TensorFlow 2.4 Migration
    • 19.3.2. Non-breaking changes
      • IPULoggingTensorHook replication_factor deprecated
      • IPUInfeedQueue/IPUOutfeedQueue/IPULoggingTensorHook feed_name deprecated
      • Change of output location for profiling information
      • Warning when epsilon value is too low
  • 19.4. Release 2.1
    • 19.4.1. Breaking changes
      • IPUPipelineEstimator change
      • Autosharding removed
      • Old IPU option configuration API changes
      • IPU Keras changes [TensorFlow 2]
    • 19.4.2. Non-breaking changes
      • Recompute suggestions deprecated
      • IPUInfeedQueue/IPUOutfeedQueue replication_factor deprecated
      • IPUInfeedQueue data_to_prefetch deprecated
      • IPUOutfeedQueue data_to_prefetch deprecated
      • CTC loss ops deprecated
      • New configuration API
      • Support for grouped collectives
      • Environment variable changes
  • 19.5. Release 2.0
    • 19.5.1. Breaking changes
    • 19.5.2. Non-breaking changes
      • IPUPipelineEstimator change
      • Autosharding deprecated
      • IPU config change
      • IPU Keras changes [TensorFlow 2]
• 20. Python API
  • 20.1. Datasets
  • 20.2. Estimators
  • 20.3. Keras
  • 20.4. Keras layers
  • 20.5. Keras losses
  • 20.6. Keras optimizers
  • 20.7. Operators
  • 20.8. Optimisers
  • 20.9. Sharding
• 21. TensorFlow operators supported by the IPU
• 22. IPU TensorFlow Addons API changes
  • 22.1. Release 2.4
• 23. IPU TensorFlow Addons Python API
  • 23.1. Keras Layers
  • 23.2. Keras Optimizers
  • 23.3. Legacy TensorFlow Layers
  • 23.4. Legacy TensorFlow Optimizers
    • 23.4.1. Optimizers made for IPU TensorFlow
• 24. Resources
  • 24.1. Graphcore
  • 24.2. TensorFlow
  • 24.3. Other
• 25. Trademarks & copyright