MIT16_410F10_lec07a

MIT16_410F10_lec07a - 1 Solving Constraint Programs using...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1 Solving Constraint Programs using Conflicts and Backjumping 6/30/11 1 Brian C. Williams 16.410-13 September 29 th , 2010 Slides draw upon material from: Prof. Patrick Prosser, Glasow University 2 Search Performance on N Queens • Standard Search • Backtracking • BT with Forward Checking • Dynamic Variable Ordering • Iterative Repair • Conflict-directed Back Jumping • A handful of queens • About 15 queens • About 30 queens • About 1,000 queens • About 10,000,000 queens (except truly hard problems) 1 2 3 4 Q Q Q Q 2 3 Back Jumping Backtracking At dead end, backup to the most recent variable . Backjumping At dead end, backup to the most recent variable that eliminated some value in the domain of the dead end variable . Example of a CSP C E D B F A G H Va Vb Vc Vd Ve Vf Vg Vh 1 = red 2 = blue 3 = green Variables and Instantiation Order Checking back Slide progression due to Prosser [4C presentation, 2003] 3 C E D B F A G H Va Vb Vc Vd Ve Vf Vg Vh 1 = red 2 = blue 3 = green Variables and Instantiation Order Checking back Find solution using Backtracking Example of a CSP C E D B F A G H Va Vb Vc Vd Ve Vf Vg Vh 1 = red 2 = blue 3 = green Variables and Instantiation Order Checking back Example of a CSP 4 C E D B F A G H Va Vb Vc Vd Ve Vf Vg Vh 1 = red 2 = blue 3 = green Variables and Instantiation Order Checking back Example of a CSP C E D B F A G H Va Vb Vc Vd Ve Vf Vg Vh 1 = red 2 = blue 3 = green Variables and Instantiation Order Checking back Example of a CSP 5 C E D B F A G H Va Vb Vc Vd Ve Vf Vg Vh 1 = red 2 = blue 3 = green Variables and Instantiation Order Checking back Example of a CSP C E D B F A G H Va Vb Vc Vd Ve Vf Vg Vh 1 = red 2 = blue 3 = green Variables and Instantiation Order Checking back Fast forward .. Example of a CSP 6 C E D B F A G H Va Vb Vc Vd Ve Vf Vg Vh 1 = red 2 = blue 3 = green Variables and Instantiation Order Checking back Example of a CSP C E D B F A G H Va Vb Vc Vd Ve Vf Vg Vh 1 = red 2 = blue 3 = green Variables and Instantiation Order Checking back Example of a CSP 7 C E D B F A G H Va Vb Vc Vd Ve Vf Vg Vh 1 = red 2 = blue 3 = green Variables and Instantiation Order...
View Full Document

This note was uploaded on 12/26/2011 for the course SCIENCE 16.410 taught by Professor Prof.brianwilliams during the Fall '10 term at MIT.

Page1 / 21

MIT16_410F10_lec07a - 1 Solving Constraint Programs using...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online