# Baseline step

A baseline step performs an experiment (a baseline experiment) and marks it as the initial experiment of a study. The purpose of the step is to build a reference configuration that Akamas can use to measure the effectiveness of an optimization conducted towards a system.

A baseline step offers three options when it comes to selecting the configuration of the baseline experiment:

* Use a configuration made with the default values of the parameters taken from the system of the study
* Use a configuration taken from an experiment of another study
* Use a custom configuration

The baseline step has the following structure:

| Field                   | Type             | Value restriction                                                                       | Is required | Default value | Description                                                                                                                                                                                                                                                                                   |
| ----------------------- | ---------------- | --------------------------------------------------------------------------------------- | ----------- | ------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `type`                  | string           | `baseline`                                                                              | yes         |               | The type of the step, in this case, `baseline`                                                                                                                                                                                                                                                |
| `name`                  | string           |                                                                                         | yes         |               | The name of the step                                                                                                                                                                                                                                                                          |
| `runOnFailure`          | boolean          | <p><code>true</code><br><code>false</code></p>                                          | no          | `false`       | <p>The execution policy of the step:</p><ul><li><code>false</code> prevents the step from running in case the previous step failed</li><li><code>true</code> allows the step to run even if the previous step failed</li></ul>                                                                |
| `from`                  | array of objects | Each object should have the structure described below                                   | no          |               | <p>The study and the experiment from which to take the configuration of the baseline experiment</p><p>The <code>from</code> and <code>experiments</code> fields are defined as an array, but it can only contain one element</p><p>This can be set only if <code>values</code> is not set</p> |
| `values`                | object           | The keys should match existing parameters                                               | no          |               | <p>The configuration with which execute the baseline experiment</p><p>This can be set only if <code>from</code> is not set</p>                                                                                                                                                                |
| `doNotRenderParameters` | string           | this cannot be used when using a *from* option since no experiment is actually executed | no          |               | Parameters not to be rendered. - see [Parameter rending](https://docs.akamas.io/akamas-docs/3.6/reference/construct-templates/study-template/parameter-rendering)                                                                                                                             |
| `renderParameters`      | string           | this cannot be used when using a *from* option since no experiment is actually executed | no          |               | Parameters to be rendered. - see [Parameter rending](https://docs.akamas.io/akamas-docs/3.6/reference/construct-templates/study-template/parameter-rendering)                                                                                                                                 |

where the `from` field should have the following structure:

```yaml
study: "study_from_which_to_take_the_baseline"
experiments: [1]
```

with

* `study` contains the name or ID of the study from which to take the configuration
* `experiments` contains the number of the experiment from which to take the configuration

### Examples

#### Baseline configuration with default values

Default values for the baseline configuration only require setting the `name` and `type` fields:

```yaml
name: "my_baseline"    # name of the step
type: "baseline"       # type of the step (baseline)
```

#### Baseline configuration from another study <a href="#baseline-configuration-taken-from-another-study" id="baseline-configuration-taken-from-another-study"></a>

The configuration taken from another study to be used as a baseline only requires setting the `from` field:

```yaml
name: "my_baseline"   # name of the step
type: "baseline"      # type of the step (baseline)
from:
  - study: "study_from_which_take_the_baseline" # name or id of the study from which to take the configuration
    experiments: [1]  # the number of the experiment from which to take the configuration
```

Notice: the `from` and `experiments` fields are defined as an array, but can only contain one element.

#### Custom baseline configuration

The custom configuration for the baseline only requires setting the `values` field:

```yaml
name: "my_baseline"         # name of the step
type: "baseline"            # type of the step (baseline)
values:
  jvm1.maxHeapSize: 1024    # parameter maxHeapSize of jvm1 is set to 1024
  jvm2.maxHeapSize: 2048    # parameter maxHeapSize of jvm2 is set to 2048
```