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README.md

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+---
+library_name: transformers
+tags: []
+---
+
+# Model Card for Model ID
+
+<!-- Provide a quick summary of what the model is/does. -->
+
+
+
+## Model Details
+
+### Model Description
+
+<!-- Provide a longer summary of what this model is. -->
+
+This is the model card of a 🤗 transformers model that has been pushed on the Hub. This model card has been automatically generated.
+
+- **Developed by:** [More Information Needed]
+- **Funded by [optional]:** [More Information Needed]
+- **Shared by [optional]:** [More Information Needed]
+- **Model type:** [More Information Needed]
+- **Language(s) (NLP):** [More Information Needed]
+- **License:** [More Information Needed]
+- **Finetuned from model [optional]:** [More Information Needed]
+
+### Model Sources [optional]
+
+<!-- Provide the basic links for the model. -->
+
+- **Repository:** [More Information Needed]
+- **Paper [optional]:** [More Information Needed]
+- **Demo [optional]:** [More Information Needed]
+
+## Uses
+
+<!-- Address questions around how the model is intended to be used, including the foreseeable users of the model and those affected by the model. -->
+
+### Direct Use
+
+<!-- This section is for the model use without fine-tuning or plugging into a larger ecosystem/app. -->
+
+[More Information Needed]
+
+### Downstream Use [optional]
+
+<!-- This section is for the model use when fine-tuned for a task, or when plugged into a larger ecosystem/app -->
+
+[More Information Needed]
+
+### Out-of-Scope Use
+
+<!-- This section addresses misuse, malicious use, and uses that the model will not work well for. -->
+
+[More Information Needed]
+
+## Bias, Risks, and Limitations
+
+<!-- This section is meant to convey both technical and sociotechnical limitations. -->
+
+[More Information Needed]
+
+### Recommendations
+
+<!-- This section is meant to convey recommendations with respect to the bias, risk, and technical limitations. -->
+
+Users (both direct and downstream) should be made aware of the risks, biases and limitations of the model. More information needed for further recommendations.
+
+## How to Get Started with the Model
+
+Use the code below to get started with the model.
+
+[More Information Needed]
+
+## Training Details
+
+### Training Data
+
+<!-- This should link to a Dataset Card, perhaps with a short stub of information on what the training data is all about as well as documentation related to data pre-processing or additional filtering. -->
+
+[More Information Needed]
+
+### Training Procedure 
+
+<!-- This relates heavily to the Technical Specifications. Content here should link to that section when it is relevant to the training procedure. -->
+
+#### Preprocessing [optional]
+
+[More Information Needed]
+
+
+#### Training Hyperparameters
+
+- **Training regime:** [More Information Needed] <!--fp32, fp16 mixed precision, bf16 mixed precision, bf16 non-mixed precision, fp16 non-mixed precision, fp8 mixed precision -->
+
+#### Speeds, Sizes, Times [optional]
+
+<!-- This section provides information about throughput, start/end time, checkpoint size if relevant, etc. -->
+
+[More Information Needed]
+
+## Evaluation
+
+<!-- This section describes the evaluation protocols and provides the results. -->
+
+### Testing Data, Factors & Metrics
+
+#### Testing Data
+
+<!-- This should link to a Dataset Card if possible. -->
+
+[More Information Needed]
+
+#### Factors
+
+<!-- These are the things the evaluation is disaggregating by, e.g., subpopulations or domains. -->
+
+[More Information Needed]
+
+#### Metrics
+
+<!-- These are the evaluation metrics being used, ideally with a description of why. -->
+
+[More Information Needed]
+
+### Results
+
+[More Information Needed]
+
+#### Summary
+
+
+
+## Model Examination [optional]
+
+<!-- Relevant interpretability work for the model goes here -->
+
+[More Information Needed]
+
+## Environmental Impact
+
+<!-- Total emissions (in grams of CO2eq) and additional considerations, such as electricity usage, go here. Edit the suggested text below accordingly -->
+
+Carbon emissions can be estimated using the [Machine Learning Impact calculator](https://mlco2.github.io/impact#compute) presented in [Lacoste et al. (2019)](https://arxiv.org/abs/1910.09700).
+
+- **Hardware Type:** [More Information Needed]
+- **Hours used:** [More Information Needed]
+- **Cloud Provider:** [More Information Needed]
+- **Compute Region:** [More Information Needed]
+- **Carbon Emitted:** [More Information Needed]
+
+## Technical Specifications [optional]
+
+### Model Architecture and Objective
+
+[More Information Needed]
+
+### Compute Infrastructure
+
+[More Information Needed]
+
+#### Hardware
+
+[More Information Needed]
+
+#### Software
+
+[More Information Needed]
+
+## Citation [optional]
+
+<!-- If there is a paper or blog post introducing the model, the APA and Bibtex information for that should go in this section. -->
+
+**BibTeX:**
+
+[More Information Needed]
+
+**APA:**
+
+[More Information Needed]
+
+## Glossary [optional]
+
+<!-- If relevant, include terms and calculations in this section that can help readers understand the model or model card. -->
+
+[More Information Needed]
+
+## More Information [optional]
+
+[More Information Needed]
+
+## Model Card Authors [optional]
+
+[More Information Needed]
+
+## Model Card Contact
+
+[More Information Needed]
+
+

config.json

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+{
+  "_name_or_path": "/home/dinalt/ai_assets/models/walsh_instruct",
+  "activation_args": {},
+  "activation_cls": "torch.nn.GELU",
+  "architectures": [
+    "HFCausalModel"
+  ],
+  "attention_args": {
+    "beta": 0.25,
+    "dropout": 0.1
+  },
+  "attention_cls": ".CausalSelfAttention",
+  "auto_map": {
+    "AutoConfig": "modelling_walsh.Config",
+    "AutoModelForCausalLM": "modelling_walsh.HFCausalModel"
+  },
+  "d_embed": 2048,
+  "dim_feedforward": 8192,
+  "dropout": 0.1,
+  "embdding_cls": "torch.nn.Embedding",
+  "embedding_args": {},
+  "feedforward_args": {
+    "beta": 0.25,
+    "bias": true
+  },
+  "feedforward_cls": ".FeedforwardLayer",
+  "head_args": {},
+  "head_cls": ".Transformer",
+  "init_gain": 1.0,
+  "layer_args": {
+    "alpha": 2.828427124746
+  },
+  "layer_cls": ".DeepnetLayer",
+  "layer_stack_args": {},
+  "layer_stack_cls": ".TransformerLayerStack",
+  "loss_function": ".causal_loss",
+  "max_sequence_length": 16384,
+  "model_type": "walsh-causal-v1",
+  "norm_args": {
+    "normalized_shape": 2084
+  },
+  "norm_cls": "torch.nn.LayerNorm",
+  "num_attention_heads": 32,
+  "num_hidden_layers": 32,
+  "output_proj_args": {},
+  "output_proj_cls": "torch.nn.Linear",
+  "pad_index": null,
+  "positional_encoder_args": {
+    "d_embed": 2048,
+    "gain": 0.3333,
+    "max_seq": 16384
+  },
+  "positional_encoder_cls": ".RSWalshPositionalEncoder",
+  "torch_dtype": "bfloat16",
+  "transformer_args": {},
+  "transformer_cls": ".Transformer",
+  "transformers_version": "4.37.2",
+  "vocab_size": 32000
+}

generation_config.json

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+{
+  "do_sample": true,
+  "eos_token_id": 3,
+  "max_new_tokens": 512,
+  "pad_token_id": 0,
+  "repetition_penalty": 1.01,
+  "temperature": 0.87,
+  "top_k": 85,
+  "top_p": 0.99,
+  "transformers_version": "4.37.2",
+  "typical_p": 0.68
+}

model.safetensors

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+version https://git-lfs.github.com/spec/v1
+oid sha256:edcfe732c6a1b9c12adfe505c30d06962f238a1ebf1c9489790a04b87ff37f6b
+size 3485189432

modelling_walsh.py

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+# See: https://huggingface.co/docs/transformers/custom_models
+from typing import Optional, Tuple, Union
+import math
+import copy
+import sys
+from importlib import import_module
+
+import torch
+from torch import nn, Tensor
+import torch.nn.init as init
+from torch.nn import functional as F
+from transformers.modeling_outputs import CausalLMOutput
+from transformers import (
+    PreTrainedModel,
+    PretrainedConfig,
+    AutoConfig,
+    AutoModel,
+    AutoModelForCausalLM,
+)
+
+from transformers.utils import (
+    is_flash_attn_2_available,
+    is_flash_attn_greater_or_equal_2_10,
+)
+
+if is_flash_attn_2_available():
+    from flash_attn import flash_attn_qkvpacked_func, flash_attn_func
+
+# The model type string to bind.
+model_type = "walsh-causal-v1"
+
+class Config(PretrainedConfig):
+    model_type = model_type
+
+    attribute_map = {
+        "hidden_size": "d_embed",
+    }
+    
+    def __init__(
+        # All of these MUST have defaults, even if unused.
+        self,
+        vocab_size=16000,
+        pad_index=None,
+        hidden_size=1024,
+        num_attention_heads=8,
+        num_hidden_layers=6,
+        max_sequence_length=2048,
+        dim_feedforward = 4096,
+        dropout=0.1,
+        loss_function = "causal_loss",
+
+        # Default class to use for each of these components.
+        positional_encoder_cls='.PositionalEncoder',
+        attention_cls='.CausalSelfAttention',
+        activation_cls='torch.nn.ReLU',
+        feedforward_cls='.FeedforwardLayer',
+        layer_stack_cls='.TransformerLayerStack',
+        layer_cls='.PostLayerNorm',
+        transformer_cls='.Transformer',
+        norm_cls='torch.nn.LayerNorm',
+        embdding_cls='torch.nn.Embedding',
+        output_proj_cls='torch.nn.Linear',
+
+        positional_encoder_args={
+            'd_model': 1024,
+            'max_seq_len': 2048,
+        },
+
+        # Arg groups, passed to factory classes above.
+        transformer_args=dict(),
+        attention_args=dict(),
+        feedforward_args=dict(),
+        activation_args=dict(),
+        norm_args={
+            'normalized_shape': 1024,
+        },
+        layer_stack_args=dict(),
+        layer_args=dict(),
+        embedding_args=dict(),
+        output_proj_args=dict(),
+        
+        **kwargs,
+    ):
+        self.vocab_size = vocab_size
+        self.pad_index = pad_index
+        self.hidden_size = hidden_size
+        self.num_attention_heads = num_attention_heads
+        self.num_hidden_layers = num_hidden_layers
+        self.max_sequence_length = max_sequence_length
+        self.loss_function = loss_function
+
+        self.dim_feedforward = dim_feedforward
+        self.dropout = dropout
+
+        self.positional_encoder_cls = positional_encoder_cls
+        self.attention_cls = attention_cls
+        self.activation_cls = activation_cls
+        self.feedforward_cls = feedforward_cls
+        self.layer_stack_cls = layer_stack_cls
+        self.layer_cls = layer_cls
+        self.transformer_cls = transformer_cls
+        self.norm_cls = norm_cls
+        self.embdding_cls = embdding_cls
+        self.output_proj_cls = output_proj_cls
+
+        self.positional_encoder_args = positional_encoder_args
+        self.transformer_args = transformer_args
+        self.attention_args = attention_args
+        self.feedforward_args = feedforward_args
+        self.activation_args = activation_args
+        self.norm_args = norm_args
+        self.layer_stack_args = layer_stack_args
+        self.layer_args = layer_args
+        self.embedding_args = embedding_args
+        self.output_proj_args = output_proj_args
+        
+        super().__init__(**kwargs)
+
+def causal_loss(logits: Tensor, labels: Tensor, input_ids: Tensor, ignore_index=-100) -> Tensor:
+        """
+        Compute and return the loss using logits and labels.
+        """
+        # Shift so that tokens < n predict n
+        shift_logits = logits[..., :-1, :].contiguous()
+        shift_labels = labels[..., 1:].contiguous()
+        
+        loss = torch.nn.functional.cross_entropy(
+            shift_logits.view(-1, shift_logits.size(-1)),
+            shift_labels.view(-1),
+            ignore_index=ignore_index,
+            reduction='mean',
+        )
+        
+        return loss.nan_to_num()
+
+# Learning to Break the Loop: Analyzing and Mitigating Repetitions for Neural Text Generation
+# https://arxiv.org/abs/2206.02369
+def ditto_loss(logits: Tensor, labels: Tensor, input_ids: Tensor) -> Tensor:
+    batch_size, seq_len, vocab_size = logits.shape
+    rep_reduce_gamma = 0.5
+    ditto_weight = 1.0e5
+    
+    probs = torch.softmax(logits, dim=-1)
+    total_loss = None
+    for i in range(batch_size):
+        context_len = labels[i, 0].item()
+        sentence_len = labels[i, 1].item()
+        n_repeats = labels[i, 2].item()
+
+        # For readability
+        context_end = context_len
+        sentence_start = context_len
+        sentence_end = sentence_start + sentence_len
+        target_start = sentence_end
+
+        # Get causal loss for context tokens
+        causal_ids = input_ids[i:i+1, :context_end]
+        c_loss = causal_loss(
+            logits=logits[i:i+1, :context_end],
+            labels=causal_ids,
+            input_ids=causal_ids
+        )
+
+        # Slice out target probabilities
+        target_probs = probs[i , target_start:, :]
+
+        # Slice out first instance of repeated sentence, detach is (prevents back-prop), repeat in N times,
+        # and trim to length of target_probs.
+        baseline_probs = probs[i, sentence_start:sentence_end, :].detach().repeat(n_repeats, 1)[:target_probs.size(0), :]
+
+        # Compute DITTO loss.
+        one_minus_probs = torch.clamp((1.0 - torch.abs((target_probs - baseline_probs * rep_reduce_gamma))), min=1e-20)
+        r_loss = -torch.log(one_minus_probs).mean() * ditto_weight
+
+        # Combine repitition and causal loss
+        loss = c_loss + r_loss
+
+        # Add this to the total
+        if total_loss is None:
+            total_loss = loss
+        else:
+            total_loss += loss
+        
+    return total_loss / batch_size
+
+ # Dynamically lookup class name and return factory for class.
+def get_dynamic_class(name):
+    try:
+        module_path, class_name = name.rsplit('.', 1)
+        if module_path == "":
+            return getattr(sys.modules[__name__], class_name)
+        module = import_module(module_path)
+        return getattr(module, class_name)
+    except (ImportError, AttributeError) as e:
+        raise ImportError(name)
+
+# An easily extensible dynamic transformer class
+# Many variations can be specified entirely in the configuration, without touching this code.
+class HFCausalModel(PreTrainedModel):
+    config_class = Config
+    model_type = 'Transformer'
+    supports_gradient_checkpointing = True
+    # Presently needs to be manually set to match transformer layer class...
+    _no_split_modules = ["DeepNetLayer"]
+    _supports_flash_attn_2 = True
+    _supports_sdpa = True
+    
+    def __init__(self, config):
+        super().__init__(config)
+        
+        self.d_model = config.hidden_size
+        self.transformer_head = self._make_transformer(config)
+        self.loss_function = get_dynamic_class(config.loss_function)
+        self.gradient_checkpointing = False
+        self.post_init()
+
+    def forward(
+        self,
+        input_ids: Optional[torch.LongTensor] = None,
+        attention_mask: Optional[torch.FloatTensor] = None,
+        token_type_ids: Optional[torch.LongTensor] = None,
+        position_ids: Optional[torch.LongTensor] = None,
+        labels: Optional[torch.LongTensor] = None,
+        output_attentions: Optional[bool] = None,
+        output_hidden_states: Optional[bool] = None,
+        return_dict: Optional[bool] = None,
+        **kwargs,
+    ) -> (Tensor, dict[str, Tensor]):
+
+        if self.gradient_checkpointing and self.training:
+            gradient_checkpointing_func = self._gradient_checkpointing_func
+        else:
+            gradient_checkpointing_func = None
+        
+        logits, attentions = self.transformer_head(
+            input_ids=input_ids,
+            need_weights=output_attentions,
+            gradient_checkpointing_func=gradient_checkpointing_func,
+        )
+        
+        # Compute loss.
+        if labels is not None:
+            loss = self.loss_function(logits=logits, labels=labels, input_ids=input_ids)
+        else:
+            loss = None
+        
+        return CausalLMOutput(loss=loss, logits=logits, attentions=attentions)
+
+    # Needed for generate() method.
+    def prepare_inputs_for_generation(self, input_ids, **kwargs):
+        attention_mask = kwargs.get("attention_mask", None)
+        model_inputs = {
+            "input_ids": input_ids,
+            "attention_mask": attention_mask,
+        }
+        return model_inputs
+
+    def _make_embedding(self, config):
+        embedding_cls = get_dynamic_class(config.embdding_cls)
+        return embedding_cls(config.vocab_size, self.d_model, config.pad_index, **config.embedding_args)
+
+    def _make_pos_encoder(self, config):
+        pos_enc_cls = get_dynamic_class(config.positional_encoder_cls)
+        return pos_enc_cls(**config.positional_encoder_args)
+
+    def _make_output_projection(self, config):
+        output_proj_cls = get_dynamic_class(config.output_proj_cls)
+        return output_proj_cls(self.d_model, config.vocab_size, **config.output_proj_args)
+
+    def _make_dropout(self, config):
+        return nn.Dropout(config.dropout)
+
+    def _make_activation(self, config):
+        activation_cls = get_dynamic_class(config.activation_cls)
+        return activation_cls(**config.activation_args)
+
+    def _make_norm(self, config):
+        norm_cls = get_dynamic_class(config.norm_cls)
+        return norm_cls(self.d_model)
+
+    def _make_self_attention(self, config):
+        attention_cls = get_dynamic_class(config.attention_cls)
+        # Map HF _attn_implementation to attn_type
+        match config._attn_implementation:
+            case "flash_attention_2":
+                if is_flash_attn_2_available():
+                    if not is_flash_attn_greater_or_equal_2_10():
+                        raise Exception("flash_attn_2 >= 2.10 is required")
+                    attn_type = "flash2"
+                else:
+                    attn_type = "torch"
+            case "sdpa":
+                attn_type = "torch"
+            case "eager":
+                attn_type = "native"
+            case _:
+                raise Exception(f"Unimplemented attention type '{config._attn_implementation}'")
+        return attention_cls(
+            d_model=self.d_model,
+            num_heads=config.num_attention_heads,
+            attn_type=attn_type,
+            **config.attention_args,
+        )
+
+    def _make_feedforward(self, config):
+        feedforward_cls = get_dynamic_class(config.feedforward_cls)
+        return feedforward_cls(
+            d_model=self.d_model,
+            feedforward_dim=config.dim_feedforward,
+            dropout=config.dropout,
+            activation=self._make_activation(config),
+            **config.feedforward_args,
+        )
+
+    def _make_layer(self, config):
+        layer_cls = get_dynamic_class(config.layer_cls)
+        return layer_cls(
+            d_model=self.d_model,
+            dropout=self._make_dropout(config),
+            attention=self._make_self_attention(config),
+            feedforward=self._make_feedforward(config),
+            norm1=self._make_norm(config),
+            norm2=self._make_norm(config),
+            **config.layer_args,
+        )
+
+    def _make_layer_stack(self, config):
+        layer_stack_cls = get_dynamic_class(config.layer_stack_cls)
+        return layer_stack_cls(
+            layers=nn.ModuleList([
+                 self._make_layer(config) for _ in range(config.num_hidden_layers)
+            ]),
+            **config.layer_stack_args,
+        )
+        
+    def _make_transformer(self, config):
+        transformer_cls = get_dynamic_class(config.transformer_cls)
+        return transformer_cls(
+            d_model=self.d_model,
+            embedding=self._make_embedding(config),
+            positional_encoder=self._make_pos_encoder(config),
+            layer_stack=self._make_layer_stack(config),
+            output_projection=self._make_output_projection(config),
+            **config.transformer_args,
+        )
+    
+    @torch.no_grad()
+    def _init_weights(self, module):
+        pass
+
+# Register model type and configuration
+AutoConfig.register(model_type, Config)
+AutoModelForCausalLM.register(Config, HFCausalModel)
+
+# A generic container class for standard transformer components.
+class Transformer(nn.Module):
+    def __init__(self, d_model, embedding, positional_encoder, layer_stack, output_projection, **kwargs):
+        super().__init__()
+        self.embedding = embedding
+        self.positional_encoder = positional_encoder
+        self.layer_stack = layer_stack
+        self.output_projection = output_projection
+        self.d_model = d_model
+        self.sqrt_d_model = d_model**0.5
+        self.reset_parameters()
+
+    def forward(self, input_ids, need_weights, gradient_checkpointing_func):
+        x = self.positional_encoder(self.embedding(input_ids) * self.sqrt_d_model)
+        
+        x, attentions = self.layer_stack(
+            x,
+            need_weights,
+            gradient_checkpointing_func,
+        )
+
+        # Translate output embedding ot logits.
+        logits = self.output_projection(x)
+        return logits, attentions
+                
+    def reset_parameters(self):
+        init.xavier_uniform_(self.output_projection.weight)
+        init.constant_(self.output_projection.bias, 0.)
+        init.normal_(self.embedding.weight, std=self.d_model**-0.5)
+
+# A vanilla positional encoder
+class PositionalEncoder(nn.Module):
+    def __init__(self, d_embed, max_seq):
+        super().__init__()
+        self.d_embed = d_embed
+        self.max_seq = max_seq
+        
+        weight = torch.zeros(max_seq, d_embed)
+        position = torch.arange(0, max_seq, dtype=torch.float).unsqueeze(1)
+        div_term = torch.exp(torch.arange(0, d_embed, 2).float() * (-math.log(10000.0) / d_embed))
+        weight[:, 0::2] = torch.sin(position * div_term)
+        weight[:, 1::2] = torch.cos(position * div_term)
+        weight = weight.unsqueeze(0)
+        self.register_buffer('weight', weight)
+
+    def forward(self, x):
+        seq_len = x.size(-2)
+        return x + self.weight[:, :seq_len]
+
+# Converts a torch array of integers into their equivalent binary codes.
+def binary_tensor(x, bits):
+    mask = 2**torch.arange(bits).to(x.device, x.dtype)
+    return x.unsqueeze(-1).bitwise_and(mask).ne(0).byte()
+
+def hadamard_walsh_matrix(k: int):
+    # k: The dimension of the matrix is 2^k
+    assert k > 0
+    
+     # Start with Hadamard H2^1 matrix.
+    h1 = torch.tensor([[1, 1], [1, -1]], dtype=torch.float)
+
+    # The series of matrices can be computed by recurisvely applying the Kronecker product,
+    # starting with h1.
+    #
+    # This will produce the series of Hadamard-Wlash matrices in natural order.
+    w = h1
+    for _ in range(k-1):
+        w = torch.kron(h1, w)
+
+    return w
+
+# This positional encoder adds absolute binary positions to the embedding, encoded via
+# Hadamard-Walsh matrix.
+#   See: https://en.wikipedia.org/wiki/Hadamard_code
+# Each bit in the binary code word is encoded via a row the Hadamard-Walsh matrix, with a
+# 1 being encoded by the presense of the row and a 0 by its absence. While training, the base
+# sequence offset is randomly selected, which appears to allow the model to generalize to 
+# sequences longer than it was trained on. This is similar to what is described here:
+# https://arxiv.org/pdf/2305.16843.pdf
+#   I have tried this approach and found that my approach works better for generalization.
+#
+# Note: Without random shifting, the early performance of this encoder is exceptionally good.
+#   The drawback is that the model can't generalize to longer sequences than it was trained on
+#   and can't easily accomidate additonal bits later in the training process.
+class RSWalshPositionalEncoder(nn.Module):
+    def __init__(self, d_embed, max_seq, gain=0.333):
+        super().__init__()
+        self.max_seq = max_seq
+        self.d_embed = d_embed
+
+        # Hadamard-Walsh k, where the dimension of the matrix is 2^k
+        k = math.ceil(math.log2(d_embed))
+
+        # The number of bits required to encode max_seq
+        bits = math.ceil(math.log2(max_seq))
+
+        # Gain controls the weight given to the encodings.
+        # When a trainable parameter, the value appears to settle at around 0.333.
+        self.gain = gain
+
+        assert bits <= d_embed, "max_seq exceeds n-bits available for d_embed"
+
+        # Generate sequential binary codes for absolute positionals.
+        # The implementation originally used Grey codes, which where successive symbols
+        # differ by by only one bit. See: https://en.wikipedia.org/wiki/Gray_code
+        # This, along with a few other coding schemes were tested, with a simple
+        # binary code having the best performance.
+        binary_code = binary_tensor(torch.arange(0, max_seq, 1), bits)
+        self.register_buffer('binary_code', binary_code, persistent=False)
+
+        # Each bit is encoded via a row of a Hadamard-Walsh matrix.
+        # We slice off the unused rows and columns -- ideally, d_embed should be
+        # the same dimension as the matrix.
+        walsh = hadamard_walsh_matrix(k)[:bits,:d_embed] * self.gain
+
+        # This alternative appears superior to the original.
+        # If starting from scratch, this use this.
+        # walsh = (hadamard_walsh_matrix(k)[:bits,:d_embed] -0.5) * self.gain
+        self.register_buffer('walsh', walsh, persistent=False)
+
+    def forward(self, x):
+        seq_len = x.size(-2)
+
+        # Get sequence of binary codes...
+        # We use a random base offset when training.
+        # This results in slower initial gains, but appears to allow the model to generalize to 
+        # the value of max_seq, even if never trained with sequences of this length. I also have
+        # a suspicion that this has a regularizing effect on training, similar to dropout. Models with
+        # random base offset shifting, despite slower initial improvement, appear to perform better in the long-run.
+        # TODO: Setup a controlled experiment to test this hypothesis.
+        if self.training:
+            shift = torch.randint(self.max_seq - seq_len + 1, (1,)).item()
+            seq = self.binary_code[shift:seq_len + shift,:]
+
+        # Disable shifting when not training. This does not appear to change the evaluation loss, but
+        # it does makes predictions easier to analyse when the attention weights are not shifting with each step.
+        else:
+            seq = self.binary_code[:seq_len,:]
+
+        # For reasons I have yet to identify, when the model is running in Textgenwebui, the matrix appears
+        # to evade conversion to bfloat16, despite everything else having been converted.
+        # This is a work-around for this.
+        self.walsh = self.walsh.to(dtype=x.dtype)
+
+        # Encode binary sequence with Hadamard-Walsh codes and apply to embeddings.
+        # If nothing else, the Walsh encodings make the positional information exceptionally 
+        # robust with respect to dropout and other adversities. They can still be easily detected
+        # at the final layer.
+        return x + (seq.to(dtype=x.dtype) @ self.walsh)
+
+# A generic stack of transformer layers.
+class TransformerLayerStack(nn.Module):
+    def __init__(self, layers):
+        super().__init__()
+        self.layers = layers
+
+    def forward(self, x, need_weights, gradient_checkpointing_func=None):
+        attentions = []
+        for layer in self.layers:
+            if gradient_checkpointing_func is not None:
+                x, attention_weights = gradient_checkpointing_func(
+                    layer.__call__,
+                    x,
+                    need_weights,
+                    use_reentrant=False
+                )
+            else:
+                x, attention_weights = layer(x, need_weights=need_weights)
+            if need_weights:
+                attentions.append(attention_weights)
+
+        return x, attentions
+
+# DeepNet: Scaling Transformers to 1,000 Layers
+# https://arxiv.org/abs/2203.00555
+class DeepnetLayer(nn.Module):
+    def __init__(
+        self,
+        d_model,
+        attention,
+        feedforward,
+        norm1,
+        norm2,
+        dropout,
+        alpha=1.0,
+    ):
+        super().__init__()
+        self.d_model = d_model
+        self.attention = attention
+        self.feedforward = feedforward
+        self.norm1 = norm1
+        self.norm2 = norm2
+        self.dropout = dropout
+        # Deepnet alpha
+        self.alpha = alpha
+
+    def forward(self, x, need_weights=False):
+        # Keep input as residual
+        residual = x * self.alpha
+
+        # Compute attention
+        x, attention_weights = self.attention(x, need_weights)
+
+        # Add attention with residual and normalize.
+        x = self.norm1(residual + self.dropout(x))
+
+        # Keep output as next residual.
+        residual = x * self.alpha
+
+        # Pass through feedforward network.
+        x = self.feedforward(x)
+
+        # Combine residual and ff output, then normalize again.
+        x = self.norm2(residual + self.dropout(x))
+
+        return x, attention_weights
+
+# A vanilla MLP transfomer layer.
+class FeedforwardLayer(nn.Module):
+    def __init__(
+        self,
+        d_model: int,
+        feedforward_dim: int,
+        dropout,
+        activation=nn.ReLU(),
+        beta=1.0,
+        bias=True,
+    ):
+        super().__init__()
+        self.d_model = d_model
+        self.beta = beta
+        self.activation = activation
+        self.linear1 = nn.Linear(d_model, feedforward_dim, bias=bias)
+        self.linear2 = nn.Linear(feedforward_dim, d_model, bias=bias)
+        self.dropout = nn.Dropout(dropout)
+        self.reset_parameters()
+
+    def forward(self, x):
+        return self.linear2(self.dropout(self.activation(self.linear1(x))))
+    
+    def reset_parameters(self):
+        init.xavier_uniform_(self.linear1.weight, gain=self.beta)
+        init.xavier_uniform_(self.linear2.weight, gain=self.beta)
+        init.constant_(self.linear1.bias, 0.)
+        init.constant_(self.linear2.bias, 0.)
+
+# GLU Variants Improve Transformer
+# https://arxiv.org/pdf/2002.05202v1.pdf
+class SwiGLUFeedforwardLayer(nn.Module):
+    def __init__(
+        self,
+        d_model,
+        d_feedforward,
+        beta=1.0,
+        dropout=0.1
+    ):
+        super().__init__()
+        self.d_model = d_model
+        self.d_feedforward = d_feedforward
+        self.beta = 1.0
+
+        self.linear1 = nn.Linear(self.d_model, self.d_feedforward * 2, bias=False)
+        self.linear2 = nn.Linear(self.d_feedforward, self.d_model, bias=False)
+        self.dropout = nn.Dropout(dropout)
+        self.reset_parameters()
+
+    def forward(self, x):
+        x, gate = self.linear1(x).chunk(2, dim=-1)
+        x = x * F.silu(gate)
+        x = self.dropout(x)
+        x = self.linear2(x)
+        return x
+
+    def reset_parameters(self):
+        # Deepnet initialization
+        # https://arxiv.org/pdf/2203.00555.pdf
+        w, g = self.linear1.weight.chunk(2, dim=0)
+        init.xavier_uniform_(w, gain=self.beta)
+        init.xavier_uniform_(g, gain=self.beta)
+        init.xavier_uniform_(self.linear2.weight, gain=self.beta)
+
+class CausalSelfAttention(nn.Module):
+    def __init__(
+        self,
+        d_model,
+        num_heads,
+        # values:
+        #   native: Use local impementation; slowest option; good for debugging; useful when experimenting with non-standard stuff.
+        #   torch: Use pytorch "scaled_dot_product_attention()"; faster; generally good compatibility; does not support returning attn weights.
+        #   flash2: Use Flash-Attention2 implementation; fastest; limited to int16 and bfloat16 types; least memory usage.
+        attn_type,
+        beta=1.0,
+        dropout=0.1,
+    ):
+        super().__init__()
+        self.d_model = d_model
+        self.num_heads = num_heads
+        self.beta = beta
+        self.attn_type = attn_type
+        
+        assert d_model % num_heads == 0, "d_model must be evenly divisible by num_heads"
+
+        # The dimension of each head.
+        self.d_head = d_model // num_heads
+
+        # We scale the attention scores by the inverse-square-root of the head dimension
+        # this shifts the temerature of softmax.
+        self.dot_product_scale = 1.0 / math.sqrt(self.d_head)
+
+        self.in_proj = nn.Linear(self.d_model, 3 * self.d_model, bias=True)
+        self.output_linear = nn.Linear(self.d_model, self.d_model, bias=True)
+
+        self.dropout = nn.Dropout(dropout)
+        self.reset_parameters()
+
+    def extra_repr(self) -> str:
+        return f'd_model={self.d_model}, num_heads={self.num_heads}, beta={self.beta}, attn_type={self.attn_type}, dropout={self.dropout}'
+        
+    def reset_parameters(self):
+        # Deepnet initialization
+        # https://arxiv.org/pdf/2203.00555.pdf
+        q, k, v = self.in_proj.weight.chunk(3)
+        init.xavier_uniform_(q, gain=1.0)
+        init.xavier_uniform_(k, gain=1.0)
+        init.xavier_uniform_(v, gain=self.beta)
+        init.xavier_uniform_(self.output_linear.weight, gain=self.beta)
+        init.constant_(self.in_proj.bias, 0.)
+        init.constant_(self.output_linear.bias, 0.)
+
+    def project_input(self, qkv):
+        proj = self.in_proj(qkv)
+        return proj.chunk(chunks=3, dim=-1)
+    
+    def forward(self, qkv, need_weights):
+        if self.attn_type == "flash2":
+            return self.flash2_forward(qkv)
+        
+        # qkv: (batch_size, seq_len, d_embed)
+        batch_size, seq_len, d_embed = qkv.shape
+        
+        # Feed the inputs through the K, Q, V matrices.
+        query, key, value = self.project_input(qkv)
+
+        # Split projections into multiple heads and swap position of sequence / heads dimension
+        query = query.view(batch_size, seq_len, self.num_heads, self.d_head).transpose(1, 2)
+        key = key.view(batch_size, seq_len, self.num_heads, self.d_head).transpose(1, 2)
+        value = value.view(batch_size, seq_len, self.num_heads, self.d_head).transpose(1, 2)
+
+        # Default to returning empty attention weights.
+        attention_weights = None
+        
+        if self.attn_type == "torch":
+            # This context manager can be used to force which implementation to use.
+            #with torch.backends.cuda.sdp_kernel(enable_flash=True, enable_math=False, enable_mem_efficient=False):
+            attended_values = F.scaled_dot_product_attention(
+                query,
+                key,
+                value,
+                attn_mask=None,
+                dropout_p=self.dropout.p if self.training else 0.0,
+                is_causal=True,
+                scale=self.dot_product_scale
+            )
+        # "native" scaled-dot-product attention implementation.
+        else:
+            # Compute attention scores
+            scores = torch.matmul(query, key.transpose(-2, -1)) * self.dot_product_scale
+
+            # Mask future positions from the past
+            scores.masked_fill_(
+                torch.tril(
+                    torch.ones(seq_len, seq_len, dtype=torch.bool, device=qkv.device),
+                    diagonal=0,
+                ).logical_not(),
+                float('-inf'),
+            )
+            
+            # Calculate the attention weights; avoid NANs that might emerge from zeros in softmax's denominator
+            attention_weights = self.dropout(torch.softmax(scores, dim=-1).clamp(min=1e-10))
+            del scores
+            
+            # Use the attention weights to get a weighted combination of value vectors
+            attended_values = torch.matmul(attention_weights, value)
+            if not need_weights:
+                del attention_weights
+                attention_weights = None
+        
+        # Concatenate attention heads and project to original embedding size using the output linear layer
+        attended_values = attended_values.transpose(1, 2).contiguous().view(batch_size, seq_len, d_embed)
+
+        # Project the concatenated output through the output matrix.
+        attended_values = self.output_linear(attended_values)
+        return attended_values, attention_weights
+        
+    def flash2_forward(self, qkv):
+        batch_size, seq_len, d_embed = qkv.shape
+        
+        # Feed the inputs through the K, Q, V matrices.
+        # query : (batch_size, seq_len, d_model)
+        # qkv : (batch_size, seq_len, 3, num_heads, d_kq)
+        qkv = self.in_proj(qkv).unflatten(
+            -1,
+            (3, self.num_heads, self.d_head)
+        )
+
+        attended_values = flash_attn_qkvpacked_func(
+            qkv.bfloat16(),
+            dropout_p=self.dropout.p if self.training else 0.0,
+            softmax_scale=self.dot_product_scale,
+            causal=True,
+        )
+        # attended_values: (batch_size, seqlen, nheads, headdim)
+
+        # Concatentate heads back into d_embed
+        attended_values = attended_values.view(batch_size, seq_len, d_embed)
+
+        # Project the concatenated output through the output matrix.
+        attended_values = self.output_linear(attended_values)
+        return attended_values, None
+
+# Attention layer with ALiBi relative positional encoding
+# TRAIN SHORT, TEST LONG: ATTENTION WITH LINEAR BIASES ENABLES INPUT LENGTH EXTRAPOLATION
+# https://arxiv.org/pdf/2108.12409.pdf
+def alibi_biases(query_len, key_len, device='cpu'):
+    x = torch.arange(key_len, device=device)[None, :]
+    y = torch.arange(query_len, device=device)[:, None]
+    return x - y
+
+class CausalAlibiAttention(nn.Module):
+    def __init__(
+        self,
+        d_model,
+        num_heads,
+        beta=1.0,
+        dropout=0.1,
+        # values:
+        #   native: Use local impementation; slowest option; good for debugging; useful when experimenting with non-standard stuff.
+        #   torch: Use pytorch "scaled_dot_product_attention()"; faster; generally good compatibility; does not support returning attn weights.
+        #   flash2: Use Flash-Attention2 implementation; fastest; limited to int16 and bfloat16 types; can't train Alibi weights; least memory usage.
+        # Note: You can perform initial training with "torch," then switch to "flash2," after the Alibi weights have settled.
+        window_size=None,
+        attn_type="native",
+        freeze_alibi=True,
+    ):
+        super().__init__()
+        self.d_model = d_model
+        self.num_heads = num_heads
+        self.beta = beta
+        self.attn_type = attn_type
+
+        assert d_model % num_heads == 0, "d_model must be evenly divisible by num_heads"
+
+        # The dimension of each head.
+        self.d_head = d_model // num_heads
+
+        # We scale the attention scores by the inverse-square-root of the head dimension
+        # this shifts the temerature of softmax.
+        self.dot_product_scale = 1.0 / math.sqrt(self.d_head)
+
+        self.in_proj = nn.Parameter(torch.empty(3 * self.d_model, self.d_model))
+        self.output_linear = nn.Linear(self.d_model, self.d_model, bias=False)
+
+        if window_size is not None:
+            self.window_size=(window_size, -1)
+        else:
+            self.window_size = (-1, -1)
+
+        self.dropout = nn.Dropout(dropout)
+
+        # This generates the original slope distribution from the paper.
+        # Observations with trainable slopes suggest that the high half of the slopes shift
+        # towards / past 1.0 and the low half approach zero or even go slightly negative.
+        # alibi_slopes = 1.0 / torch.logspace(1, 8, self.num_heads, base=2, dtype=torch.float)
+
+        # These appear to work better, as initial values, in practice.
+        alibi_slopes = 1.0 / torch.logspace(0, 7, self.num_heads, base=2, dtype=torch.float)
+
+        # If not trainable, it can improve performance somewhat if the low half are set to zero. Apparently
+        # making roughly half of the slopes position-agnostic is somehow closer to optimal?
+        # alibi_slopes.masked_fill_(torch.where(torch.arange(0, self.num_heads) >= (self.num_heads / 2), True, False), 0)
+
+        self.alibi_slopes = nn.Parameter(alibi_slopes)
+
+        # Optionally, allow/disallow training of ALiBi slopes.
+        self.alibi_slopes.requires_grad = (not freeze_alibi)
+        self.reset_parameters()
+
+    def extra_repr(self) -> str:
+        return f'd_model={self.d_model}, num_heads={self.num_heads}, beta={self.beta}, attn_type={self.attn_type}, window_size={self.window_size}, dropout={self.dropout}'
+
+    def reset_parameters(self):
+        # Deepnet initialization
+        # https://arxiv.org/pdf/2203.00555.pdf
+
+        q, k, v = self.in_proj.chunk(3)
+        init.xavier_uniform_(q, gain=1.0)
+        init.xavier_uniform_(k, gain=1.0)
+        init.xavier_uniform_(v, gain=self.beta)
+        init.xavier_uniform_(self.output_linear.weight, gain=self.beta)
+
+    def project_input(self, qkv):
+        proj = F.linear(qkv, self.in_proj)
+        return proj.chunk(chunks=3, dim=-1)
+
+    def forward(self, qkv, need_weights):
+        if self.attn_type == "flash2":
+            return self.flash2_forward(qkv)
+
+        # qkv: (batch_size, seq_len, d_embed)
+        batch_size, seq_len, d_embed = qkv.shape
+
+        # Feed the inputs through the K, Q, V matrices.
+        query, key, value = self.project_input(qkv)
+
+        # Split projections into multiple heads and swap position of sequence / heads dimension
+        query = query.view(batch_size, seq_len, self.num_heads, self.d_head).transpose(1, 2)
+        key = key.view(batch_size, seq_len, self.num_heads, self.d_head).transpose(1, 2)
+        value = value.view(batch_size, seq_len, self.num_heads, self.d_head).transpose(1, 2)
+
+        # Apply Alibi relative positional biases.
+        attn_bias = alibi_biases(seq_len, seq_len, device=query.device) * self.alibi_slopes.view(-1, 1, 1)
+
+        # Mask future positions from the past
+        causal_mask = torch.tril(torch.ones(seq_len, seq_len, dtype=torch.bool, device=qkv.device), diagonal=0)
+        attn_bias.masked_fill_(causal_mask.logical_not(), float('-inf'))
+        del causal_mask
+
+        # Default to returning empty attention weights.
+        attention_weights = None
+
+        if self.attn_type == "torch":
+            # This context manager can be used to force which implementation to use.
+            #with torch.backends.cuda.sdp_kernel(enable_flash=True, enable_math=False, enable_mem_efficient=False):
+            attended_values = F.scaled_dot_product_attention(
+                query,
+                key,
+                value,
+                attn_mask=attn_bias.to(dtype=query.dtype),
+                dropout_p=self.dropout.p if self.training else 0.0,
+                is_causal=False,
+                scale=self.dot_product_scale
+            )
+        # "native" scaled-dot-product attention implementation.
+        else:
+            # Compute attention scores
+            scores = torch.matmul(query, key.transpose(-2, -1)) * self.dot_product_scale
+
+            # Adjust scores with attn_mask
+            scores += attn_bias
+
+            # Calculate the attention weights; avoid NANs that might emerge from zeros in softmax's denominator
+            attention_weights = self.dropout(torch.softmax(scores, dim=-1).clamp(min=1e-10))
+
+            # Use the attention weights to get a weighted combination of value vectors
+            attended_values = torch.matmul(attention_weights, value)
+            if not need_weights:
+                attention_weights = None
+
+        # Concatenate attention heads and project to original embedding size using the output linear layer
+        attended_values = attended_values.transpose(1, 2).contiguous().view(batch_size, seq_len, d_embed)
+
+        # Project the concatenated output through the output matrix.
+        attended_values = self.output_linear(attended_values)
+        return attended_values, attention_weights
+
+    def flash2_forward(self, qkv):
+        batch_size, seq_len, d_embed = qkv.shape
+
+        # Feed the inputs through the K, Q, V matrices.
+        # query : (batch_size, seq_len, d_model)
+        # qkv : (batch_size, seq_len, 3, num_heads, d_kq)
+        qkv = F.linear(
+            qkv,
+            self.in_proj,
+        ).unflatten(
+            -1,
+            (3, self.num_heads, self.d_head)
+        )
+
+        attended_values = flash_attn_qkvpacked_func(
+            qkv.bfloat16(),
+            dropout_p=self.dropout.p if self.training else 0.0,
+            softmax_scale=self.dot_product_scale,
+            causal=True,
+            window_size=self.window_size,
+            alibi_slopes=self.alibi_slopes.float(),
+        ).to(dtype=qkv.dtype)
+        # attended_values: (batch_size, seqlen, nheads, headdim)
+
+        # Concatentate heads back into d_embed
+        attended_values = attended_values.view(batch_size, seq_len, d_embed)
+
+        # Project the concatenated output through the output matrix.
+        attended_values = self.output_linear(attended_values)
+        return attended_values, None