diff --git a/.gitignore b/.gitignore
index 24d0d7e..413a029 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 checkpoints/*
 !checkpoints/README.md
+pytorch/grok-1-*
diff --git a/pytorch/configuration_grok_1.py b/pytorch/configuration_grok_1.py
new file mode 100644
index 0000000..1026df3
--- /dev/null
+++ b/pytorch/configuration_grok_1.py
@@ -0,0 +1,67 @@
+from transformers import PretrainedConfig
+
+# Copied from huggingface/transformers configuration_mixtral.py.
+# Modified to default values provided by xai-org/grok-1 run.py.
+class Grok1Config(PretrainedConfig):
+    model_type = "grok-1"
+    keys_to_ignore_at_inference = ["past_key_values"]
+
+    def __init__(
+        self,
+        vocab_size=131072,
+        max_position_embeddings=8192,
+        output_multiplier_scale=0.5773502691896257,
+        embedding_multiplier_scale=78.38367176906169,
+        hidden_size=6144,
+        intermediate_size=32768,
+        num_hidden_layers=64,
+        num_attention_heads=48,
+        attn_output_multiplier=0.08838834764831845,
+        num_key_value_heads=8,
+        hidden_act="gelu",
+        initializer_range=0.02,
+        rms_norm_eps=1e-5,
+        use_cache=True,
+        pad_token_id=0,
+        bos_token_id=2,
+        eos_token_id=2,
+        tie_word_embeddings=False,
+        rope_theta=int(1e4),
+        attention_dropout=0.0,
+        num_experts_per_tok=2,
+        num_local_experts=8,
+        output_router_logits=False,
+        **kwargs,
+    ):
+        self.vocab_size = vocab_size
+        self.max_position_embeddings = max_position_embeddings
+        self.output_multiplier_scale = output_multiplier_scale,
+        self.embedding_multiplier_scale = embedding_multiplier_scale
+        self.hidden_size = hidden_size
+        self.intermediate_size = intermediate_size
+        self.num_hidden_layers = num_hidden_layers
+        self.num_attention_heads = num_attention_heads
+        self.attn_output_multiplier = attn_output_multiplier
+
+        # For backward compatibility.
+        if num_key_value_heads is None:
+            num_key_value_heads = num_attention_heads
+
+        self.num_key_value_heads = num_key_value_heads
+        self.hidden_act = hidden_act
+        self.initializer_range = initializer_range
+        self.rms_norm_eps = rms_norm_eps
+        self.use_cache = use_cache
+        self.rope_theta = rope_theta
+        self.attention_dropout = attention_dropout
+
+        self.num_experts_per_tok = num_experts_per_tok
+        self.num_local_experts = num_local_experts
+        self.output_router_logits = output_router_logits
+        super().__init__(
+            pad_token_id=pad_token_id,
+            bos_token_id=bos_token_id,
+            eos_token_id=eos_token_id,
+            tie_word_embeddings=tie_word_embeddings,
+            **kwargs,
+        )
diff --git a/pytorch/modeling_grok_1.py b/pytorch/modeling_grok_1.py
new file mode 100644
index 0000000..45a6b6f
--- /dev/null
+++ b/pytorch/modeling_grok_1.py
@@ -0,0 +1,401 @@
+from configuration_grok_1 import Grok1Config
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+from transformers import PreTrainedModel
+from transformers.activations import ACT2FN
+from typing import Optional, NamedTuple, List
+
+class TiedWeightEmbedding(nn.Embedding):
+    """Module for tied weight embedding."""
+
+    def __init__(
+        self,
+        config: Grok1Config,
+    ):
+        super().__init__(
+            num_embeddings=config.vocab_size,
+            embedding_dim=config.hidden_size,
+            padding_idx=config.pad_token_id,
+        )
+
+    def decode(
+        self,
+        inputs: torch.Tensor,
+    ) -> torch.Tensor:
+        return torch.matmul(inputs, self.weight.T)
+
+class Gating(nn.Module):
+    """Gating module for spare MoE expert selection."""
+
+    def __init__(
+        self,
+        config: Grok1Config,
+    ):
+        super().__init__()
+        self.router_weights = nn.Linear(config.hidden_size, config.num_local_experts, bias=False)
+
+    def forward(
+        self,
+        inputs: torch.Tensor,
+        padding_mask: Optional[torch.Tensor] = None,
+    ):
+        routing_logits = self.router_weights(inputs)
+        routing_probs = F.softmax(routing_logits, dim=-1, dtype=torch.float32)
+
+        if padding_mask is not None:
+            # [batch * seq, expert]
+            routing_probs = routing_probs * padding_mask.view(-1).unsqueeze(-1)
+
+        # Note routing_probs is using float32.
+        return routing_probs, routing_logits
+
+class MLPExpert(nn.Module):
+    """MLP expert module for sparse MoE."""
+
+    def __init__(
+        self,
+        config: Grok1Config,
+    ):
+        super().__init__()
+        self.w1 = nn.Linear(config.hidden_size, config.intermediate_size, bias=False)
+        self.v = nn.Linear(config.hidden_size, config.intermediate_size, bias=False)
+        self.dense = nn.Linear(config.intermediate_size, config.hidden_size, bias=False)
+        self.act_fn = ACT2FN[config.hidden_act]
+
+    def forward(
+        self,
+        inputs: torch.Tensor,
+    ) -> torch.Tensor:
+        h_w1 = self.act_fn(self.w1(inputs))
+        h_v = self.v(inputs)
+        h_dense = self.dense(h_w1 * h_v)
+        return h_dense
+
+class SparseMoEMLP(nn.Module):
+    """Sparse MoE MLP module."""
+
+    def __init__(
+        self,
+        config: Grok1Config,
+    ):
+        super().__init__()
+        self.num_experts = config.num_local_experts
+        self.top_k = config.num_experts_per_tok
+        self.gating = Gating(config)
+        self.experts = nn.ModuleList([MLPExpert(config) for _ in range(self.num_experts)])
+
+    def forward(
+        self,
+        hidden_states: torch.Tensor,
+        padding_mask: Optional[torch.Tensor] = None,
+    ) -> torch.Tensor:
+        batch_size, sequence_length, hidden_dim = hidden_states.shape
+        hidden_states = hidden_states.view(-1, hidden_dim)
+
+        # Get routing probabilities and selected experts.
+        routing_probs, routing_logits = self.gating(hidden_states, padding_mask)
+        routing_probs, selected_experts = torch.topk(routing_probs, self.top_k, dim=-1)
+        routing_probs = routing_probs / routing_probs.sum(dim=-1, keepdim=True)
+        # Now routing_probs is using the hidden_states' dtype instead of float32.
+        routing_probs = routing_probs.to(hidden_states.dtype)
+
+        # Initialize output hidden states.
+        final_hidden_states = torch.zeros(
+            (batch_size * sequence_length, hidden_dim),
+            dtype=hidden_states.dtype,
+            device=hidden_states.device,
+        )
+
+        # Create expert mask.
+        expert_mask = F.one_hot(selected_experts, num_classes=self.num_experts).permute(2, 1, 0)
+
+        # Loop over experts and compute their contributions.
+        for expert_idx in range(self.num_experts):
+            expert_layer = self.experts[expert_idx]
+            idx, top_x = torch.where(expert_mask[expert_idx])
+
+            if top_x.shape[0] == 0:
+                continue
+
+            top_x_list = top_x.tolist()
+            idx_list = idx.tolist()
+
+            current_state = hidden_states[None, top_x_list].reshape(-1, hidden_dim)
+            current_hidden_states = expert_layer(current_state) * routing_probs[top_x_list, idx_list, None]
+
+            final_hidden_states.index_add_(0, top_x, current_hidden_states.to(hidden_states.dtype))
+
+        final_hidden_states = final_hidden_states.reshape(batch_size, sequence_length, hidden_dim)
+        return final_hidden_states, routing_logits
+
+def rotate_half(x: torch.Tensor) -> torch.Tensor:
+    x1, x2 = x.chunk(2, dim=-1)
+    return torch.cat((-x2, x1), dim=-1)
+
+class RotaryPositionalEmbedding(nn.Module):
+
+    def __init__(
+        self,
+        dim: int,
+        base_exponent: int = int(1e4),
+    ):
+        super().__init__()
+        self.dim = dim
+        self.base_exponent = base_exponent
+        assert self.dim % 2 == 0, "Embedding dimension must be even for rotary embeddings."
+
+    def forward(
+        self,
+        x: torch.Tensor,
+        seq_dim: int,
+        offset: torch.Tensor,
+        const_position: Optional[int] = None,
+        t: Optional[torch.Tensor] = None,
+    ) -> torch.Tensor:
+        # Compute the per-dimension frequencies.
+        dtype = x.dtype
+        exponents = torch.arange(0, self.dim, 2, dtype=torch.float32, device=x.device)
+        inv_freq = (self.base_exponent ** (exponents / self.dim)).reciprocal()
+
+        if not isinstance(offset, torch.Tensor):
+            offset = torch.tensor(offset, dtype=torch.float32, device=x.device)
+        if offset.dim() == 0:
+            # Offset can be a scalar or one offset per batch element.
+            offset = offset.unsqueeze(0)
+
+        # Compute the per-element phase (to pass into sin and cos).
+        if const_position is not None:
+            t = const_position * torch.ones(
+                (1, x.shape[seq_dim]),
+                dtype=torch.float32,
+                device=x.device,
+            )
+        elif t is None:
+            t = torch.arange(x.shape[seq_dim], dtype=torch.float32, device=x.device)
+            t = t.unsqueeze(0) + offset.unsqueeze(-1)
+
+        phase = torch.einsum("bi,j->bij", t, inv_freq)
+        phase = torch.cat([phase, phase], dim=-1)[:, :, None, :]
+
+        x_rotated = x * phase.cos() + rotate_half(x) * phase.sin()
+
+        return x_rotated.to(dtype)
+
+class RMSNorm(nn.Module):
+
+    def __init__(self, hidden_size, eps=1e-5):
+        super().__init__()
+        self.weight = nn.Parameter(torch.ones(hidden_size))
+        self.eps = eps
+
+    def forward(self, hidden_states):
+        input_dtype = hidden_states.dtype
+        hidden_states = hidden_states.to(torch.float32)
+        variance = hidden_states.pow(2).mean(-1, keepdim=True)
+        hidden_states = hidden_states * torch.rsqrt(variance + self.eps)
+        return self.weight * hidden_states.to(input_dtype)
+
+class KVMemory(NamedTuple):
+    k: Optional[torch.Tensor]
+    v: Optional[torch.Tensor]
+    step: Optional[torch.Tensor]
+
+def init_layer_memories(
+    batch_size: int,
+    sequence_len: int,
+    num_kv_heads: int,
+    key_size: int,
+    num_layers: int,
+    step: Optional[torch.Tensor] = None,
+    dtype: torch.dtype = torch.bfloat16,
+    device: str = "cpu",
+):
+    if step is None:
+        step = torch.zeros(batch_size, dtype=torch.int32, device=device)
+    return [
+        KVMemory(
+            k=torch.zeros(batch_size, sequence_len, num_kv_heads, key_size, dtype=dtype, device=device),
+            v=torch.zeros(batch_size, sequence_len, num_kv_heads, key_size, dtype=dtype, device=device),
+            step=step,
+        )
+        for _ in range(num_layers)
+    ]
+
+class MultiHeadAttention(nn.Module):
+
+    def __init__(self, config: Grok1Config):
+        super().__init__()
+        self.num_q_heads = config.num_attention_heads
+        self.num_kv_heads = config.num_key_value_heads
+        self.key_size = config.hidden_size // config.num_attention_heads
+        self.value_size = self.key_size
+        self.attn_output_multiplier = config.attn_output_multiplier
+
+        self.q_proj = nn.Linear(config.hidden_size, self.num_q_heads * self.key_size, bias=False)
+        self.k_proj = nn.Linear(config.hidden_size, self.num_kv_heads * self.key_size, bias=False)
+        self.v_proj = nn.Linear(config.hidden_size, self.num_kv_heads * self.value_size, bias=False)
+        self.out_proj = nn.Linear(self.num_q_heads * self.value_size, config.hidden_size, bias=False)
+        self.rotary_pos_emb = RotaryPositionalEmbedding(self.key_size, base_exponent=config.rope_theta)
+
+    def forward(
+        self,
+        hidden_states: torch.Tensor,
+        mask: Optional[torch.Tensor] = None,
+        layer_memory: Optional[KVMemory] = None,
+    ):
+        batch_size, seq_len, _ = hidden_states.shape
+
+        query = self.q_proj(hidden_states).view(batch_size, seq_len, self.num_q_heads, self.key_size)
+        key = self.k_proj(hidden_states).view(batch_size, seq_len, self.num_kv_heads, self.key_size)
+        value = self.v_proj(hidden_states).view(batch_size, seq_len, self.num_kv_heads, self.value_size)
+
+        query = self.rotary_pos_emb(query, seq_dim=1, offset=layer_memory.step if layer_memory else 0)
+        key = self.rotary_pos_emb(key, seq_dim=1, offset=layer_memory.step if layer_memory else 0)
+
+        if layer_memory:
+            key = torch.cat([layer_memory.k, key], dim=1)
+            value = torch.cat([layer_memory.v, value], dim=1)
+            new_step = layer_memory.step + seq_len
+            memory_mask = torch.arange(key.shape[1], device=key.device) < new_step[:, None]
+            memory_mask = memory_mask[:, None, None, :]
+            if mask is not None:
+                mask = mask * memory_mask
+            else:
+                mask = memory_mask
+            new_memory = KVMemory(k=key, v=value, step=new_step)
+        else:
+            new_memory = None
+
+        query = query.view(batch_size, seq_len, self.num_kv_heads, self.num_q_heads // self.num_kv_heads, self.key_size)
+        attn_logits = torch.einsum("...thHd,...Thd->...hHtT", query, key).to(torch.float32)
+        attn_logits *= self.attn_output_multiplier
+        max_attn_val = torch.tensor(30.0, dtype=attn_logits.dtype, device=attn_logits.device)
+        attn_logits = max_attn_val * torch.tanh(attn_logits / max_attn_val)
+
+        if mask is not None:
+            mask = mask[:, :, None, :, :]
+            attn_logits = torch.where(mask, attn_logits, torch.full_like(attn_logits, float("-inf")))
+
+        attn_weights = F.softmax(attn_logits, dim=-1).to(query.dtype)
+
+        attn = torch.einsum("...hHtT,...Thd->...thHd", attn_weights, value)
+        attn = attn.reshape(batch_size, seq_len, -1)
+        attn = self.out_proj(attn)
+
+        return attn, new_memory
+
+class Decoder(nn.Module):
+
+    def __init__(self, config: Grok1Config):
+        super().__init__()
+        self.num_layers = config.num_hidden_layers
+        self.attention = MultiHeadAttention(config)
+        self.norm1 = RMSNorm(config.hidden_size)
+        self.norm2 = RMSNorm(config.hidden_size)
+        self.norm3 = RMSNorm(config.hidden_size)
+        self.norm4 = RMSNorm(config.hidden_size)
+
+        if config.num_local_experts > 1:
+            self.mlp = SparseMoEMLP(config)
+        else:
+            self.mlp = MLPExpert(config)
+
+    def forward(
+        self,
+        hidden_states: torch.Tensor,
+        mask: Optional[torch.Tensor] = None,
+        padding_mask: Optional[torch.Tensor] = None,
+        layer_memory: Optional[KVMemory] = None,
+    ):
+        residual = hidden_states
+        hidden_states = self.norm1(hidden_states)
+        attn_output, new_memory = self.attention(hidden_states, mask, layer_memory)
+        attn_output = self.norm2(attn_output)
+        hidden_states = residual + attn_output
+
+        residual = hidden_states
+        hidden_states = self.norm3(hidden_states)
+        if isinstance(self.mlp, SparseMoEMLP):
+            mlp_output, routing_logits = self.mlp(hidden_states, padding_mask)
+        else:
+            mlp_output = self.mlp(hidden_states)
+            routing_logits = None
+        mlp_output = self.norm4(mlp_output)
+        hidden_states = residual + mlp_output
+
+        return hidden_states, new_memory, routing_logits
+
+class Grok1PreTrainedModel(PreTrainedModel):
+    config_class = Grok1Config
+    base_model_prefix = "model"
+    supports_gradient_checkpointing = True
+    _no_split_modules = ["Decoder"]
+    _skip_keys_device_placement = "past_key_values"
+    _supports_flash_attn_2 = False
+    _supports_sdpa = False
+    _supports_cache_class = True
+
+    def _init_weights(self, module):
+        std = self.config.initializer_range
+        if isinstance(module, nn.Linear):
+            module.weight.data.normal_(mean=0.0, std=std)
+            if module.bias is not None:
+                module.bias.data.zero_()
+        elif isinstance(module, nn.Embedding):
+            module.weight.data.normal_(mean=0.0, std=std)
+            if module.padding_idx is not None:
+                module.weight.data[module.padding_idx].zero_()
+
+class Grok1ForCausalLM(Grok1PreTrainedModel):
+
+    def __init__(self, config: Grok1Config):
+        super().__init__(config)
+        self.embedding = TiedWeightEmbedding(self.config)
+        self.layers = nn.ModuleList([Decoder(self.config) for _ in range(self.config.num_hidden_layers)])
+        self.norm = RMSNorm(self.config.hidden_size)
+
+    def forward(
+        self,
+        input_ids: torch.Tensor,
+        attention_mask: Optional[torch.Tensor] = None,
+        memory: Optional[List[KVMemory]] = None,
+        last_hid_only: bool = False,
+        length: Optional[torch.Tensor] = None,
+    ):
+        batch_size, seq_len = input_ids.shape
+        if attention_mask is None:
+            attention_mask = torch.ones_like(input_ids, dtype=torch.bool)
+        else:
+            attention_mask = attention_mask.bool()
+
+        padding_mask = attention_mask.view(batch_size, seq_len)
+        causal_mask = torch.tril(torch.ones(1, 1, seq_len, seq_len, dtype=torch.bool, device=input_ids.device))
+        mask = padding_mask[:, None, None, :] * causal_mask
+
+        hidden_states = self.embedding(input_ids) * self.config.embedding_multiplier_scale
+        kv_memories = []
+
+        for i, layer in enumerate(self.layers):
+            layer_memory = memory[i] if memory else None
+            hidden_states, new_memory, routing_logits = layer(
+                hidden_states,
+                mask,
+                padding_mask,
+                layer_memory,
+            )
+            kv_memories.append(new_memory)
+
+        hidden_states = self.norm(hidden_states)
+
+        if last_hid_only:
+            last_step = torch.maximum(torch.sum(padding_mask, dim=1) - 1, torch.tensor(0, device=input_ids.device))
+            hidden_states = hidden_states[torch.arange(batch_size, device=input_ids.device), last_step]
+        elif length is not None:
+            last_step = torch.maximum(length - 1, torch.tensor(0, device=input_ids.device))
+            hidden_states = hidden_states[torch.arange(batch_size, device=input_ids.device), last_step]
+            hidden_states = hidden_states.unsqueeze(1)
+
+        logits = self.embedding.decode(hidden_states) * torch.tensor(self.config.output_multiplier_scale, dtype=hidden_states.dtype, device=hidden_states.device)
+
+        return logits, kv_memories