Type:	Package
Title:	Running Local LLMs with 'llama.cpp' Backend
Version:	1.0.1
Date:	2025-10-08
Description:	The 'localLLM' package provides R bindings to the 'llama.cpp' library for running large language models. The package uses a lightweight architecture where the C++ backend library is downloaded at runtime rather than bundled with the package. Package features include text generation, reproducible generation, and parallel inference.
License:	MIT + file LICENSE
Depends:	R (≥ 3.6.0)
Imports:	Rcpp (≥ 1.0.14), tools, utils
Suggests:	testthat (≥ 3.0.0), covr
URL:	https://github.com/EddieYang211/localLLM
BugReports:	https://github.com/EddieYang211/localLLM/issues
SystemRequirements:	C++17, libcurl (optional, for model downloading)
Encoding:	UTF-8
LazyData:	true
RoxygenNote:	7.3.2
NeedsCompilation:	yes
Packaged:	2025-10-08 22:18:08 UTC; yaoshengleo
Author:	Eddie Yang [aut], Yaosheng Xu [aut, cre]
Maintainer:	Yaosheng Xu <xu2009@purdue.edu>
Repository:	CRAN
Date/Publication:	2025-10-15 19:10:08 UTC

R Interface to llama.cpp with Runtime Library Loading

Description

Provides R bindings to the llama.cpp library for running large language models locally. This package uses an innovative lightweight architecture where the C++ backend library is downloaded at runtime rather than bundled with the package, enabling zero-configuration AI inference in R with enterprise-grade performance.

Details

The localLLM package brings state-of-the-art language models to R users through a carefully designed four-layer architecture that combines ease of use with high performance.

## Quick Start 1. Install the R package: install.packages("localLLM") 2. Download backend library: install_localLLM() 3. Start generating text: quick_llama("Hello, how are you?")

## Key Features

• Zero Configuration: One-line setup with automatic model downloading

• High Performance: Native C++ inference engine with GPU support

• Cross Platform: Pre-compiled binaries for Windows, macOS, and Linux

• Memory Efficient: Smart caching and memory management

• Production Ready: Robust error handling and comprehensive documentation

## Architecture Overview The package uses a layered design:

• High-Level API: quick_llama for simple text generation

• Mid-Level API: model_load, generate for detailed control

• Low-Level API: Direct access to tokenization and context management

• C++ Backend: llama.cpp engine with dynamic loading

## Main Functions

• install_localLLM - Download and install backend library

• quick_llama - High-level text generation (recommended for beginners)

• model_load - Load GGUF models with smart caching

• context_create - Create inference contexts

• generate - Generate text with full parameter control

• tokenize / detokenize - Text <-> Token conversion

• apply_chat_template - Format conversations for chat models

## Example Workflows

### Basic Text Generation

# Simple one-liner
response <- quick_llama("Explain quantum computing")

# With custom parameters
creative_text <- quick_llama("Write a poem about AI", 
                             temperature = 0.9, 
                             max_tokens = 150)

### Advanced Usage with Custom Models

# Load your own model
model <- model_load("path/to/your/model.gguf")
ctx <- context_create(model, n_ctx = 4096)

# Direct text generation with auto-tokenization
output <- generate(ctx, "The future of AI is", max_tokens = 100)

### Batch Processing

# Process multiple prompts efficiently
prompts <- c("Summarize AI trends", "Explain machine learning", "What is deep learning?")
responses <- quick_llama(prompts)

## Supported Model Formats The package works with GGUF format models from various sources:

• Hugging Face Hub (automatic download)

• Local .gguf files

• Custom quantized models

• Ollama-compatible models

## Performance Tips

• Use n_gpu_layers = -1 to fully utilize GPU acceleration

• Set n_threads to match your CPU cores for optimal performance

• Use larger n_ctx values for longer conversations

• Enable use_mlock for frequently used models to prevent swapping

Author(s)

Eddie Yang and Yaosheng Xu <xu2009@purdue.edu>

References

https://github.com/EddieYang211/localLLM

See Also

Useful links:

• https://github.com/EddieYang211/localLLM

• Report bugs at https://github.com/EddieYang211/localLLM/issues

Temporarily apply an HF token for a scoped operation

Description

This helper sets the 'HF_TOKEN' environment variable for the duration of a code block and restores the previous value afterwards.

Usage

.with_hf_token(token, expr)

Arguments

AG News classification sample

Description

A 100-row subset of the AG News Topic Classification dataset consisting of 25 documents from each of the four classes (World, Sports, Business, Sci/Tech). The sample is intended for quick demonstrations and tests without requiring the full external dataset.

Usage

data(ag_news_sample)

Format

A data frame with 100 rows and 3 character columns:

class

News topic label ("World", "Sports", "Business", or "Sci/Tech").

title

Headline of the news article.

description

Short description for the article.

Details

The sample was obtained from textdata::dataset_ag_news() (Zhang et al., 2015) using a fixed random seed to ensure reproducibility. It is provided solely for illustrative purposes.

Source

Zhang, X., Zhao, J., & LeCun, Y. (2015). "Character-level Convolutional Networks for Text Classification." arXiv:1509.01626. Original data distributed via the AG News Topic Classification dataset.

See Also

[textdata::dataset_ag_news()]

Apply Chat Template to Format Conversations

Description

Formats conversation messages using the model's built-in chat template or a custom template. This is essential for chat models that expect specific formatting for multi-turn conversations.

Usage

apply_chat_template(model, messages, template = NULL, add_assistant = TRUE)

Arguments

Value

Formatted prompt string ready for text generation

See Also

model_load, quick_llama, generate

Examples

## Not run: 
# Load a chat model
model <- model_load("path/to/chat_model.gguf")

# Format a conversation
messages <- list(
  list(role = "system", content = "You are a helpful assistant."),
  list(role = "user", content = "What is machine learning?"),
  list(role = "assistant", content = "Machine learning is..."),
  list(role = "user", content = "Give me an example.")
)

# Apply chat template
formatted_prompt <- apply_chat_template(model, messages)

# Generate response
response <- quick_llama(formatted_prompt)

## End(Not run)

Apply Gemma-Compatible Chat Template

Description

Creates a properly formatted chat template for Gemma models, which use <start_of_turn> and <end_of_turn> markers instead of ChatML format. This function addresses compatibility issues with apply_chat_template() when used with Gemma models.

Usage

apply_gemma_chat_template(messages, add_assistant = TRUE)

Arguments

Value

A character string with properly formatted Gemma chat template

Examples

## Not run: 
messages <- list(
  list(role = "system", content = "You are a helpful assistant."),
  list(role = "user", content = "Hello!")
)
formatted <- apply_gemma_chat_template(messages)

## End(Not run)

Free localLLM backend

Description

Clean up backend resources. Usually called automatically.

Usage

backend_free()

Value

No return value, called for side effects (frees backend resources).

Initialize localLLM backend

Description

Initialize the backend library. This should be called once before using other functions.

Usage

backend_init()

Value

No return value, called for side effects (initializes backend).

Create Inference Context for Text Generation

Description

Creates a context object that manages the computational state for text generation. The context maintains the conversation history and manages memory efficiently for processing input tokens and generating responses. Each model can have multiple contexts with different settings.

Usage

context_create(
  model,
  n_ctx = 2048L,
  n_threads = 4L,
  n_seq_max = 1L,
  verbosity = 1L
)

Arguments

Value

A context object (external pointer) used for text generation with generate

See Also

model_load, generate, tokenize

Examples

## Not run: 
# Load model and create basic context
model <- model_load("path/to/model.gguf")
ctx <- context_create(model)

# Create context with larger buffer for long conversations
long_ctx <- context_create(model, n_ctx = 4096)

# High-performance context with more threads
fast_ctx <- context_create(model, n_ctx = 2048, n_threads = 8)

# Context for batch processing multiple conversations
batch_ctx <- context_create(model, n_ctx = 2048, n_seq_max = 4)

# Create context with minimal verbosity (quiet mode)
quiet_ctx <- context_create(model, verbosity = 2L)

## End(Not run)

Convert Token IDs Back to Text

Description

Converts a sequence of integer token IDs back into human-readable text. This is the inverse operation of tokenization and is typically used to convert model output tokens into text that can be displayed to users.

Usage

detokenize(model, tokens)

Arguments

Value

Character string containing the decoded text corresponding to the input tokens

See Also

tokenize, generate, model_load

Examples

## Not run: 
# Load model
model <- model_load("path/to/model.gguf")

# Tokenize then detokenize (round-trip)
original_text <- "Hello, how are you today?"
tokens <- tokenize(model, original_text)
recovered_text <- detokenize(model, tokens)
print(recovered_text)  # Should match original_text

# Generate and display text
ctx <- context_create(model)
generated_text <- generate(ctx, "The weather is", max_tokens = 10)

# Inspect individual tokens
single_token <- c(123)  # Some token ID
token_text <- detokenize(model, single_token)
print(paste("Token", single_token, "represents:", token_text))

## End(Not run)

Download a model manually

Description

Download a model manually

Usage

download_model(
  model_url,
  output_path = NULL,
  show_progress = TRUE,
  verify_integrity = TRUE,
  max_retries = 3,
  hf_token = NULL
)

Arguments

Value

The path where the model was saved

Examples

## Not run: 
# Download to specific location
download_model(
  "https://example.com/model.gguf",
  file.path(tempdir(), "my_model.gguf")
)

# Download to cache (path will be returned)
cached_path <- download_model("https://example.com/model.gguf")

## End(Not run)

Generate Text Using Language Model Context

Description

Generates text using a loaded language model context with automatic tokenization. Simply provide a text prompt and the model will handle tokenization internally. This function now has a unified API with generate_parallel.

Usage

generate(
  context,
  prompt,
  max_tokens = 100L,
  top_k = 40L,
  top_p = 1,
  temperature = 0,
  repeat_last_n = 0L,
  penalty_repeat = 1,
  seed = 1234L,
  clean = FALSE
)

Arguments

Value

Character string containing the generated text

See Also

quick_llama, generate_parallel, context_create

Examples

## Not run: 
# Load model and create context
model <- model_load("path/to/model.gguf")
ctx <- context_create(model, n_ctx = 2048)

response <- generate(ctx, "Hello, how are you?", max_tokens = 50)

# Creative writing with higher temperature
story <- generate(ctx, "Once upon a time", max_tokens = 200, temperature = 0.8)

# Prevent repetition
no_repeat <- generate(ctx, "Tell me about AI",
                     repeat_last_n = 64,
                     penalty_repeat = 1.1)

# Clean output (remove special tokens)
clean_output <- generate(ctx, "Explain quantum physics", clean = TRUE)

## End(Not run)

Generate Text in Parallel for Multiple Prompts

Description

Generate Text in Parallel for Multiple Prompts

Usage

generate_parallel(
  context,
  prompts,
  max_tokens = 100L,
  top_k = 40L,
  top_p = 1,
  temperature = 0,
  repeat_last_n = 0L,
  penalty_repeat = 1,
  seed = 1234L,
  progress = FALSE,
  clean = FALSE
)

Arguments

Value

Character vector of generated texts

Get Backend Library Path

Description

Returns the full path to the installed localLLM backend library.

Usage

get_lib_path()

Details

This function will throw an error if the backend library is not installed. Use lib_is_installed to check installation status first.

Value

Character string containing the path to the backend library file.

See Also

lib_is_installed, install_localLLM

Examples

## Not run: 
# Get the library path (only if installed)
if (lib_is_installed()) {
  lib_path <- get_lib_path()
  message("Library is at: ", lib_path)
}

## End(Not run)

Get the model cache directory

Description

Get the model cache directory

Usage

get_model_cache_dir()

Value

Path to the directory where models are cached

Install localLLM Backend Library

Description

This function downloads and installs the pre-compiled C++ backend library required for the localLLM package to function.

Usage

install_localLLM()

Details

This function downloads platform-specific pre-compiled binaries from GitHub releases. The backend library is stored in the user's data directory and loaded at runtime. Internet connection is required for the initial download.

Value

Returns NULL invisibly. Called for side effects.

See Also

lib_is_installed, get_lib_path

Examples

## Not run: 
# Install the backend library
install_localLLM()

## End(Not run)

Check if Backend Library is Installed

Description

Checks whether the localLLM backend library has been downloaded and installed.

Usage

lib_is_installed()

Value

Logical value indicating whether the backend library is installed.

See Also

install_localLLM, get_lib_path

Examples

# Check if backend library is installed
if (lib_is_installed()) {
  message("Backend library is ready")
} else {
  message("Please run install_localLLM() first")
}

List cached models on disk

Description

Enumerates the models that have been downloaded to the local cache. This is useful when you want to reuse a previously downloaded model but no longer remember the original URL. The cache directory can be overridden with the 'LOCALLLM_CACHE_DIR' environment variable or via the 'cache_dir' argument.

Usage

list_cached_models(cache_dir = NULL)

Arguments

Value

A data frame with one row per cached model and the columns 'name' (file name), 'path' (absolute path), 'size_bytes', and 'modified'. Returns an empty data frame when no models are cached.

Load Language Model with Automatic Download Support

Description

Loads a GGUF format language model from local path or URL with intelligent caching and download management. Supports various model sources including Hugging Face, Ollama repositories, and direct HTTPS URLs. Models are automatically cached to avoid repeated downloads.

Usage

model_load(
  model_path,
  cache_dir = NULL,
  n_gpu_layers = 0L,
  use_mmap = TRUE,
  use_mlock = FALSE,
  show_progress = TRUE,
  force_redownload = FALSE,
  verify_integrity = TRUE,
  check_memory = TRUE,
  hf_token = NULL,
  verbosity = 1L
)

Arguments

Value

A model object (external pointer) that can be used with context_create, tokenize, and other model functions

See Also

context_create, download_model, get_model_cache_dir, list_cached_models

Examples

## Not run: 
# Load local GGUF model
model <- model_load("/path/to/my_model.gguf")

# Download from Hugging Face and cache locally
hf_path = "https://huggingface.co/Qwen/Qwen3-0.6B-GGUF/resolve/main/Qwen3-0.6B-Q8_0.gguf"
model <- model_load(hf_path)

# Load with GPU acceleration (offload 10 layers)
model <- model_load("/path/to/model.gguf", n_gpu_layers = 10)

# Download to custom cache directory
model <- model_load(hf_path, 
                    cache_dir = file.path(tempdir(), "my_models"))

# Force fresh download (ignore cache)
model <- model_load(hf_path, 
                    force_redownload = TRUE)

# High-performance settings for large models
model <- model_load("/path/to/large_model.gguf", 
                    n_gpu_layers = -1,     # All layers on GPU
                    use_mlock = TRUE)      # Lock in memory

# Load with minimal verbosity (quiet mode)
model <- model_load("/path/to/model.gguf", verbosity = 2L)

## End(Not run)

Quick LLaMA Inference

Description

A high-level convenience function that provides one-line LLM inference. Automatically handles model downloading, loading, and text generation with optional chat template formatting and system prompts for instruction-tuned models.

Usage

quick_llama(
  prompt,
  model = .get_default_model(),
  n_threads = NULL,
  n_gpu_layers = "auto",
  n_ctx = 2048L,
  verbosity = 1L,
  max_tokens = 100L,
  top_k = 40L,
  top_p = 1,
  temperature = 0,
  repeat_last_n = 0L,
  penalty_repeat = 1,
  min_p = 0.05,
  system_prompt = "You are a helpful assistant.",
  auto_format = TRUE,
  chat_template = NULL,
  stream = FALSE,
  seed = 1234L,
  progress = interactive(),
  clean = TRUE,
  ...
)

Arguments

Value

Character string (single prompt) or named list (multiple prompts)

See Also

model_load, generate, generate_parallel, install_localLLM

Examples

## Not run: 
# Simple usage with default settings (deterministic)
response <- quick_llama("Hello, how are you?")

# Raw text generation without chat template
raw_response <- quick_llama("Complete this: The capital of France is",
                           auto_format = FALSE)

# Custom system prompt
code_response <- quick_llama("Write a Python hello world program",
                            system_prompt = "You are a Python programming expert.")

# Creative writing with higher temperature
creative_response <- quick_llama("Tell me a story",
                                 temperature = 0.8,
                                 max_tokens = 200)

# Prevent repetition
no_repeat <- quick_llama("Explain AI",
                        repeat_last_n = 64,
                        penalty_repeat = 1.1)

# Multiple prompts (parallel processing)
responses <- quick_llama(c("Summarize AI", "Explain quantum computing"),
                        max_tokens = 150)

## End(Not run)

Reset quick_llama state

Description

Clears cached model and context objects, forcing fresh initialization on the next call to quick_llama().

Usage

quick_llama_reset()

Value

No return value, called for side effects (resets cached state).

Configure Hugging Face access token

Description

Utility helper to manage the 'HF_TOKEN' environment variable used for authenticated downloads from Hugging Face. The token is set for the current R session, and it can optionally be persisted to a '.Renviron' file for future sessions. The token is not printed back to the console.

Usage

set_hf_token(token, persist = FALSE, renviron_path = NULL)

Arguments

Value

Invisibly returns the currently active token value.

Examples

## Not run: 
set_hf_token("hf_xxx")
tmp_env <- file.path(tempdir(), ".Renviron_localLLM")
set_hf_token("hf_xxx", persist = TRUE, renviron_path = tmp_env)

## End(Not run)

Smart Chat Template Application

Description

Automatically detects the model type and applies the appropriate chat template. For Gemma models, uses the Gemma-specific format. For other models, falls back to the standard apply_chat_template function.

Usage

smart_chat_template(model, messages, template = NULL, add_assistant = TRUE)

Arguments

Value

Formatted chat template string

Convert Text to Token IDs

Description

Converts text into a sequence of integer token IDs that the language model can process. This is the first step in text generation, as models work with tokens rather than raw text. Different models may use different tokenization schemes (BPE, SentencePiece, etc.).

Usage

tokenize(model, text, add_special = TRUE)

Arguments

Value

Integer vector of token IDs corresponding to the input text. These can be used with generate for text generation or detokenize to convert back to text

See Also

detokenize, generate, model_load

Examples

## Not run: 
# Load model
model <- model_load("path/to/model.gguf")

# Basic tokenization
tokens <- tokenize(model, "Hello, world!")
print(tokens)  # e.g., c(15339, 11, 1917, 0)

# Tokenize without special tokens (for model inputs)
raw_tokens <- tokenize(model, "Continue this text", add_special = FALSE)

# Tokenize multiple texts
batch_tokens <- tokenize(model, c("First text", "Second text"))

# Check tokenization of specific phrases
question_tokens <- tokenize(model, "What is AI?")
print(length(question_tokens))  # Number of tokens

## End(Not run)

Test tokenize function (debugging)

Description

Test tokenize function (debugging)

Usage

tokenize_test(model)

Arguments

Value

Integer vector of tokens for "H"