From 12b21e1d27f43deaa748419919b40b80cedd0ddd Mon Sep 17 00:00:00 2001 From: Tim Dwyer Date: Wed, 12 Jul 2006 00:55:58 +0000 Subject: Previously graph layout was done using the Kamada-Kawai layout algorithm implemented in Boost. I am replacing this with a custom implementation of a constrained stress-majorization algorithm. The stress-majorization algorithm is more robust and has better convergence characteristics than Kamada-Kawai, and also simple constraints can be placed on node position (for example, to enforce downward-pointing edges, non-overlap constraints, or cluster constraints). Another big advantage is that we no longer need Boost. I've tested the basic functionality, but I have yet to properly handle disconnected graphs or to properly scale the resulting layout. This commit also includes significant refactoring... the quadratic program solver - libvpsc (Variable Placement with Separation Constraints) has been moved to src/libvpsc and the actual graph layout algorithm is in libcola. (bzr r1394) --- src/libvpsc/constraint.cpp | 47 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 src/libvpsc/constraint.cpp (limited to 'src/libvpsc/constraint.cpp') diff --git a/src/libvpsc/constraint.cpp b/src/libvpsc/constraint.cpp new file mode 100644 index 000000000..7c200878b --- /dev/null +++ b/src/libvpsc/constraint.cpp @@ -0,0 +1,47 @@ +/** + * \brief A constraint determines a minimum or exact spacing required between + * two variables. + * + * Authors: + * Tim Dwyer + * + * Copyright (C) 2005 Authors + * + * Released under GNU LGPL. Read the file 'COPYING' for more information. + */ + +#include "constraint.h" +#include +Constraint::Constraint(Variable *left, Variable *right, double gap, bool equality) +: left(left), + right(right), + gap(gap), + timeStamp(0), + active(false), + visited(false), + equality(equality) +{ + left->out.push_back(this); + right->in.push_back(this); +} +Constraint::~Constraint() { + Constraints::iterator i; + for(i=left->out.begin(); i!=left->out.end(); i++) { + if(*i==this) break; + } + left->out.erase(i); + for(i=right->in.begin(); i!=right->in.end(); i++) { + if(*i==this) break; + } + right->in.erase(i); +} +std::ostream& operator <<(std::ostream &os, const Constraint &c) +{ + if(&c==NULL) { + os<<"NULL"; + } else { + const char *type=c.equality?"=":"<="; + os<<*c.left<<"+"<