public Builder setTopP(float value) {

      topP_ = value;
      bitField0_ |= 0x00000002;
      onChanged();
      return this;
    }
<pre>
Optional. If specified, nucleus sampling will be used.
</pre>

<code>optional float top_p = 2 [(.google.api.field_behavior) = OPTIONAL];</code>

@param value The topP to set.
@return This builder for chaining.
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/GenerationConfig.java