In this paper, the SHARK integral generation and digestion engine is described. In essence, SHARK is based on a reformulation of the popular McMurchie/Davidson approach to molecular integrals. This reformulation leads to an efficient algorithm that is driven by BLAS level 3 operations. The algorithm is particularly efficient for high angular momentum basis functions (up to L = 7 is available by default, but the algorithm is programmed for arbitrary angular momenta). SHARK features a significant number of specific programming constructs that are designed to greatly simplify the workflow in quantum chemical program development and avoid undesirable code duplication to the largest possible extent. SHARK can handle segmented, generally and partially generally contracted basis sets. It can be used to generate a host of one- and two-electron integrals over various kernels including, two-, three-, and four-index repulsion integrals, integrals over Gauge Including Atomic Orbitals (GIAOs), relativistic integrals and integrals featuring a finite nucleus model. SHARK provides routines to evaluate Fock like matrices, generate integral transformations and related tasks. SHARK is the essential engine inside the ORCA package that drives essentially all tasks that are related to integrals over basis functions in version ORCA 5.0 and higher. Since the core of SHARK is based on low-level basic linear algebra (BLAS) operations, it is expected to not only perform well on present day but also on future hardware provided that the hardware manufacturer provides a properly optimized BLAS library for matrix and vector operations. Representative timings and comparisons to the Libint library used by ORCA are reported for Intel i9 and Apple M1 max processors.

中文翻译：

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SHARK积分生成消化系统

在本文中，描述了SHARK积分生成和消化引擎。本质上，SHARK 是基于对流行的 McMurchie/Davidson 分子积分方法的重新表述。这种重构导致了一种由 BLAS 3 级操作驱动的高效算法。该算法对于高角动量基函数（高达L = 7 默认情况下可用，但该算法针对任意角动量进行了编程）。SHARK 具有大量特定的编程结构，旨在极大地简化量子化学程序开发的工作流程，并最大程度地避免不必要的代码重复。SHARK 可以处理分段、一般和部分一般收缩基组。它可用于在各种内核上生成大量单电子和双电子积分，包括双、三和四指数排斥积分、规范包括原子轨道 (GIAO) 的积分、相对论积分和具有有限核模型。SHARK 提供例程来评估 Fock 类矩阵、生成积分变换和相关任务。SHARK 是 ORCA 包中的基本引擎，它基本上驱动与 ORCA 5.0 及更高版本中的基函数积分相关的所有任务。由于 SHARK 的核心基于低级基本线性代数 (BLAS) 运算，因此如果硬件制造商为矩阵和向量提供适当优化的 BLAS 库，则预计它不仅在现在而且在未来的硬件上都能表现良好操作。针对 Intel i9 和 Apple M1 max 处理器报告了具有代表性的时序和与 ORCA 使用的 Libint 库的比较。如果硬件制造商为矩阵和向量运算提供适当优化的 BLAS 库，则预计它不仅在现在而且在未来的硬件上都能表现良好。针对 Intel i9 和 Apple M1 max 处理器报告了具有代表性的时序和与 ORCA 使用的 Libint 库的比较。如果硬件制造商为矩阵和向量运算提供适当优化的 BLAS 库，则预计它不仅在现在而且在未来的硬件上都能表现良好。针对 Intel i9 和 Apple M1 max 处理器报告了具有代表性的时序和与 ORCA 使用的 Libint 库的比较。