4.8 Logistic Regression Limits

There are some limits that apply for the creation of any BigML resource. These are limits based on the number of classes, terms and items that can be considered to create your models. This is explained in Field Limits .

Additionally, some specific limits apply for your logistic regressions visualization, i.e. to the logistic regression chart and the coefficient table views, depending on the number of classes in the objective field and the number of input fields in your dataset. See subsection 4.8.2 and subsection 4.8.1 for a detailed explanation.

Note: chart limits and coefficient table limits just affect to the visualization of the model, i.e., despite your dataset reach those limits, you can still creating the logistic regression, evaluating it and using it to make predictions.

Field Limits

Logistic regression, similarly to other BigML models, has the following limitations according to the type of field:

• Classes: a maximum number of 1,000 distinct classes per field is allowed.

• Terms: BigML can handle up to 1,000 terms in total. If multiple text fields are defined, then the token limit per field is evenly divided by the number of text fields evenly, e.g., a dataset with two text fields would result in 500 terms per text field. BigML selects those terms with most significant frequency, discarding both those that appear either too often or too infrequently. A maximum of 256 characters per term is allowed.

• Items: a maximum number of 10,000 distinct items per field is allowed.

4.8.1 Chart Limits

There are some circumstances under which your chart cannot be displayed:

• As the chart only supports numeric fields for the x-axis, if your logistic regression only contains categorical, text, or items fields, the chart cannot be displayed. The view displayed by default will be the coeffcient table. When you try to click on the chart icon you will see a warning message. (See Figure 4.134 .)

  

• If your logistic regression contains more than 100 fields the chart cannot be displayed and again the default view will be the table view. When you try to click on the chart icon, you will see the warning message shown in Figure 4.135 .

  

• If your logistic regression contains more than 200 categories in the objective field, neither the chart nor the table can be displayed and you will see the warning message shown in Figure 4.136 . You can still see your coefficients by downloading the CSV file.

  

4.8.2 Coefficient Table Limits

If your logistic regression contains more than 1,000 fields and/or more than 200 categories in the objective field, the table cannot be displayed. You will need to download the CSV if you want to see your logistic regression coefficients. You will get the message shown in Figure 4.137 :