The Surrogate Modeling Toolbox (SMT) is an open-source Python package that offers a collection of surrogate modeling methods, sampling techniques, and a set of sample problems. This paper presents SMT 2.0, a major new release of SMT that introduces significant upgrades and new features to the toolbox. This release adds the capability to handle mixed-variable surrogate models and hierarchical variables. These types of variables are becoming increasingly important in several surrogate modeling applications. SMT 2.0 also improves SMT by extending sampling methods, adding new surrogate models, and computing variance and kernel derivatives for Kriging. This release also includes new functions to handle noisy and use multifidelity data. To the best of our knowledge, SMT 2.0 is the first open-source surrogate library to propose surrogate models for hierarchical and mixed inputs. This open-source software is distributed under the New BSD license.

翻译：代理建模工具箱（SMT）是一个开源的Python软件包，提供了一系列代理建模方法、采样技术以及一组示例问题。本文介绍了SMT 2.0这一重要新版本，该版本对工具箱进行了重大升级并添加了新功能。此版本新增了处理混合变量代理模型和分层变量的能力，这类变量在若干代理建模应用中正变得日益重要。SMT 2.0还通过扩展采样方法、新增代理模型以及计算克里金法的方差与核函数导数来改进SMT。该版本还新增了处理噪声数据和使用多保真数据的功能。据我们所知，SMT 2.0是首个面向分层输入与混合输入提出代理模型的开源代理库。该开源软件基于New BSD许可证进行分发。