This tutorial will walk you through a simple example of writing and adding a custom eval. The example eval will test the model's ability to do basic arithmetic. We will assume that you have followed the setup instructions in the README and gone through the other docs for how to run and build evals.
When writing your own evals, the primary files of interest are:
evals/api.py, which provides common interfaces and utilities used by eval creators to sample from models and process the results,evals/record.py, which defines the recorder classes which log eval results in different ways, such as to a local JSON file or to a remote Snowflake database, andevals/metrics.py, which defines various common metrics of interest.
These files provide a suite of tools for writing new evals. Once you have gone through this tutorial, you can see a more realistic example of these tools in action with the machine translation eval example, which also implements custom eval logic in lieu of using an existing template.
The first step is to create the datasets for your eval. Here, we will create toy train and test sets of just two examples each. The test examples are what we will evaluate the model on, and we'll include the train examples as few-shot examples in the prompt to the model.
We will use the new chat format described here. By default, we encourage all evals to be written using chat formatting if you want to evaluate our new models. Under the hood, we convert chat formatted data into raw strings for older non chat models.
To create the toy datasets, in your terminal, type:
echo -e '[{"role": "system", "content": "2+2=", "name": "example_user"}, {"role": "system", "content": "4", "name": "example_assistant"}]\n[{"role": "system", "content": "4*4=", "name": "example_user"}, {"role": "system", "content": "16", "name": "example_assistant"}]' > /tmp/train.jsonl
echo -e '[{"role": "system", "content": "48+2=", "name": "example_user"}, {"role": "system", "content": "50", "name": "example_assistant"}]\n[{"role": "system", "content": "5*20=", "name": "example_user"}, {"role": "system", "content": "100", "name": "example_assistant"}]' > /tmp/test.jsonlThe next step is to write a Python class that represents the actual evaluation. This class uses your datasets to create prompts, which are passed to the model to generate completions. Evaluation classes generally will inherit from the evals.Eval base class (defined in evals/eval.py) and will override two methods: eval_sample and run.
Let's create a file called arithmetic.py under the evals/elsuite folder. We'll start by defining the eval class. Its __init__ method will take in the arguments we need (references to the train and test sets) along with other kwargs that will be handled by the base class. We'll also define the run method which takes in a recorder and returns the final metrics of interest.
import random
import textwrap
import evals
import evals.metrics
class Arithmetic(evals.Eval):
def __init__(self, train_jsonl, test_jsonl, train_samples_per_prompt=2, **kwargs):
super().__init__(**kwargs)
self.train_jsonl = train_jsonl
self.test_jsonl = test_jsonl
self.train_samples_per_prompt = train_samples_per_prompt
def run(self, recorder):
"""
Called by the `oaieval` CLI to run the eval. The `eval_all_samples` method calls `eval_sample`.
"""
self.train_samples = evals.get_jsonl(self.train_jsonl)
test_samples = evals.get_jsonl(self.test_jsonl)
self.eval_all_samples(recorder, test_samples)
# Record overall metrics
return {
"accuracy": evals.metrics.get_accuracy(recorder.get_events("match")),
}Generally, most run methods will follow the same pattern shown here: loading the data, calling eval_all_samples, and aggregating the results (in this case, using the get_accuracy function in evals/metrics.py). eval_all_samples takes in both the recorder and the test_samples and, under the hood, will call the eval_sample method on each sample in test_samples. So let's write that eval_sample method now:
def eval_sample(self, test_sample, rng: random.Random):
"""
Called by the `eval_all_samples` method to evaluate a single sample.
ARGS
====
`test_sample`: a line from the JSONL test file
`rng`: should be used for any randomness that is needed during evaluation
This method does the following:
1. Generate a prompt that contains the task statement, a few examples, and the test question.
2. Check if the model generates the correct answer.
"""
stuffing = rng.sample(self.train_samples, self.train_samples_per_prompt)
prompt = [
{"role": "system", "content": "Solve the following math problems"},
]
for i, sample in enumerate(stuffing + [test_sample]):
if i < len(stuffing):
prompt += [
{"role": "system", "content": sample["problem"], "name": "example_user"},
{"role": "system", "content": sample["answer"], "name": "example_assistant"},
]
else:
prompt += [{"role": "user", "content": sample["problem"]}]
evals.check_sampled_text(self.model_spec, prompt, expected=sample["answer"])You'll notice that eval_sample doesn't take the recorder as an argument. This is because eval_all_samples sets it to be the default recorder before calling eval_sample, and the recording utilities defined in evals/record.py use the default recorder. In this example, the eval_sample method passes off a lot of the heavy lifting to the evals.check_sampled_text utility function, which is defined in evals/api.py. This utility function queries the model, defined by self.model_spec, with the given prompt and checks to see if the result matches the expected answer (or one of them, if given a list). It then records these matches (or non matches) using the default recorder.
eval_sample methods may vary greatly based on your use case. If you are building custom evals, it is a good idea to be familiar with the functions available to you in evals/record.py, evals/metrics.py, and especially evals/api.py.
The next step is to register your eval in the registry so that it can be run using the oaieval CLI.
Let's create a file called arithmetic.yaml under the evals/registry/evals folder and add an entry for our eval as follows:
# Define a base eval
arithmetic:
# id specifies the eval that this eval is an alias for
# in this case, arithmetic is an alias for arithmetic.dev.match-v1
# When you run `oaieval davinci arithmetic`, you are actually running `oaieval davinci arithmetic.dev.match-v1`
id: arithmetic.dev.match-v1
# The metrics that this eval records
# The first metric will be considered to be the primary metric
metrics: [accuracy]
description: Evaluate arithmetic ability
# Define the eval
arithmetic.dev.match-v1:
# Specify the class name as a dotted path to the module and class
class: evals.elsuite.arithmetic:Arithmetic
# Specify the arguments as a dictionary of JSONL URIs
# These arguments can be anything that you want to pass to the class constructor
args:
train_jsonl: /tmp/train.jsonl
test_jsonl: /tmp/test.jsonlThe args field should match the arguments that your eval class __init__ method expects.
The final step is to run your eval and view the results.
pip install . # you can omit this if you used `pip install -e .` to install
oaieval gpt-3.5-turbo arithmeticIf you run with the gpt-3.5-turbo model, you should see an output similar to this (we have cleaned up the output here slightly for readability):
% oaieval gpt-3.5-turbo arithmetic
... [registry.py:147] Loading registry from .../evals/registry/evals
... [registry.py:147] Loading registry from .../.evals/evals
... [oaieval.py:139] Run started: <run_id>
... [eval.py:32] Evaluating 2 samples
... [eval.py:138] Running in threaded mode with 1 threads!
100%|██████████████████████████████████████████| 2/2 [00:00<00:00, 3.35it/s]
... [record.py:320] Final report: {'accuracy': 1.0}. Logged to /tmp/evallogs/<run_id>_gpt-3.5-turbo_arithmetic.jsonl
... [oaieval.py:170] Final report:
... [oaieval.py:172] accuracy: 1.0
... [record.py:309] Logged 6 rows of events to /tmp/evallogs/<run_id>_gpt-3.5-turbo_arithmetic.jsonl: insert_time=2.038ms
If you notice evals has cached your data and you need to clear that cache, you can do so with rm -rf /tmp/filecache.