| # llama.cpp/examples/imatrix | |
| Compute an importance matrix for a model and given text dataset. Can be used during quantization to enchance the quality of the quantized models. | |
| More information is available here: https://github.com/ggerganov/llama.cpp/pull/4861 | |
| ## Usage | |
| ``` | |
| ./llama-imatrix \ | |
| -m model.gguf -f some-text.txt [-o imatrix.dat] [--process-output] [--verbosity 1] \ | |
| [--no-ppl] [--chunk 123] [--output-frequency 10] [--save-frequency 0] \ | |
| [--in-file imatrix-prev-0.dat --in-file imatrix-prev-1.dat ...] | |
| ``` | |
| Here `-m` with a model name and `-f` with a file containing training data (such as e.g. `wiki.train.raw`) are mandatory. | |
| The parameters in square brackets are optional and have the following meaning: | |
| * `-o` (or `--output-file`) specifies the name of the file where the computed data will be stored. If missing `imatrix.dat` is used. | |
| * `--verbosity` specifies the verbosity level. If set to `0`, no output other than the perplexity of the processed chunks will be generated. If set to `1`, each time the results are saved a message is written to `stderr`. If `>=2`, a message is output each time data is collected for any tensor. Default verbosity level is `1`. | |
| * `--output-frequency` specifies how often the so far computed result is saved to disk. Default is 10 (i.e., every 10 chunks) | |
| * `--save-frequency` specifies how often to save a copy of the imatrix in a separate file. Default is 0 (i.e., never) | |
| * `--process-output` specifies if data will be collected for the `output.weight` tensor. My experience is that it is better to not utilize the importance matrix when quantizing `output.weight`, so this is set to `false` by default. | |
| For faster computation, make sure to use GPU offloading via the `-ngl` argument | |
| ## Example | |
| ```bash | |
| # generate importance matrix (imatrix.dat) | |
| ./llama-imatrix -m ggml-model-f16.gguf -f train-data.txt -ngl 99 | |
| # use the imatrix to perform a Q4_K_M quantization | |
| ./llama-quantize --imatrix imatrix.dat ggml-model-f16.gguf ./ggml-model-q4_k_m.gguf q4_k_m | |
| ``` | |