Clad version 0.3

Introduction

This document contains the release notes for the automatic differentiation plugin for clang Clad, release 0.3. Clad is built on top of Clang and LLVM compiler infrastructure. Here we describe the status of Clad in some detail, including major improvements from the previous release and new feature work.

Note that if you are reading this file from a git checkout, this document applies to the next release, not the current one.

What's New in Clad 0.3?

Some of the major new features and improvements to Clad are listed here. Generic improvements to Clad as a whole or to its underlying infrastructure are described first.

External Dependencies

• clang-5.0

Misc

• Improvements in both Forward and Reverse mode:

  • Better correctness of C++ constructs -- handle scopes properly; allow proper
    variable shadowing; and preserve namespaces.

• Forward Mode:

  • Efficient evaluation in forward mode -- for given:

  double t = std::sin(x) * std::cos(x);

  is converted into:

  double _t0 = std::sin(x);
  double _t1 = std::cos(x);
  double _d_t = sin_darg0(x) * (_d_x) * _t1 + _t0 * cos_darg0(x) * (_d_x);
  double t = _t0 * _t1;

  instead of

  double _d_t = sin_darg0(x) * (_d_x) * cos(x) + sin(x) * cos_darg0(x) * (_d_x);
  double t = sin(x) * cos(x);

  to avoid re-evaluation.

  • Reduced cloning complexity -- the recursive cloning of complexity O(n^2) is
    replaced by cloning the whole tree at once yielding O(2n).

  • Handle more C++ constructs -- variable reassignments and for loops.

Fixed Bugs

Issue 47
Issue 92

Special Kudos

This release wouldn't have happened without the efforts of our contributors,
listed in the form of Firstname Lastname (#contributions):

FirstName LastName (#commits)

Aleksandr Efremov (6)
Vassil Vassilev (2)