MejorA DE LA EfiCIENCIA DE resolución DEL SISTEMA TOY(FD) Y SU aplicación A PROBLEMAS REALES DE LA INDUSTRIA TESIS DoctorAL Ignacio CastiñeirAS Pérez Directores Fernando Sáenz Pérez FrANCISCO Javier López FrAGUAS Universidad Complutense DE Madrid Facultad DE Informática Departamento DE Sistemas Informáticos Y Computación Madrid, MARZO DE 2014 Improving THE Solving EffiCIENCY OF TOY(FD) AND ITS Application TO Real-Life Problems PhD Thesis Ignacio CastiñeirAS Pérez Advisors Fernando Sáenz Pérez FrANCISCO Javier López FrAGUAS Complutense Univesity OF Madrid Faculty OF Information TECHNOLOGY AND Computer Science Departament OF Information Systems AND Computing Madrid, March OF 2014 MejorA DE LA EfiCIENCIA DE resolución DEL SISTEMA TOY(FD) Y SU aplicación A PROBLEMAS REALES DE LA INDUSTRIA Improving THE Solving EffiCIENCY OF TOY(FD) AND ITS Application TO Real-Life Problems Ignacio CastiñeirAS Pérez TESIS DOCTORal, CON título “MejorA DE LA EfiCIENCIA DE resolución DEL SISTEMA TOY(FD) Y SU aplicación A PROBLEMAS REALES DE LA INDUSTRIA”, PRESENTADA POR Ignacio CastiñeirAS Pérez PARA LA obtención DEL título DE Doctor POR LA Universi- DAD Complutense DE Madrid. Título: MejorA DE LA EfiCIENCIA DE resolución DEL SISTEMA TOY(FD) Y SU aplicación A PROBLEMAS REALES DE LA INDUSTRIA Autor: Ignacio CastiñeirAS Pérez ([email protected]) Directores: Fernando Sáenz Pérez ([email protected]) FrANCISCO Javier López FrAGUAS ([email protected]) Universidad Complutense DE Madrid, Facultad DE Informática, Departamento DE Sistemas Informáticos Y Computación Madrid, MARZO DE 2014 PhD Thesis, WITH TITLE “Improving THE Solving EffiCIENCY OF TOY(FD) AND ITS Ap- PLICATION TO Real-Life Problems”, PRESENTED BY Ignacio CastiñeirAS Pérez FOR ob- TAINING A PhD AT THE Complutense University OF Madrid. Títle: Improving THE Solving EffiCIENCY OF TOY(FD) AND ITS Application TO Real-Life Problems Author: Ignacio CastiñeirAS Pérez ([email protected]) Advisors: Fernando Sáenz Pérez ([email protected]) FrANCISCO Javier López FrAGUAS ([email protected]) Complutense Univesity OF Madrid, Faculty OF Information TECHNOLOGY AND Com- PUTER Science, Departament OF Information Systems AND Computing Madrid, March OF 2014 - As YOU requested, WE TOOK SOME fiBRE SAMPLES FROM NordberG’S jacket. Use THIS MICROSCOPE TO TAKE A LOOK FOR yourself. - I CAN’T SEE anything. - Use YOUR OPEN eye, Frank. - Yeah, I CAN SEE IT now. Lab MANAGER TED Olsen (Ed Williams), CAPTAIN Ed Hocken (GeorGE Kennedy) AND LIEUTENANT FrANK Drebin (Leslie Nielsen). The Naked Gun, 1988. Acknowledgements The DAY I JOINED THE DeclarATIVE ProgrAMMING Group (GPD) FOR STARTING THE MASTER PROGRAM IT WAS MY 24th birthday, AND THE DAY I AM fiNISHING THIS PhD THESIS IS THE 23rd BIRTHDAY OF MY sister. If I WANTED TO ENCOURAGE HER FOR JOINING A post-grADUATE PROGRam, I WOULD NOT KNOW WHAT TO say. Research has, AS ANY OTHER discipline, SEVERAL ADVANTAGES AND DRawbacks. But, IF I THINK back, IT HAS GIVEN ME TWO MAYOR points, WHICH I WANT TO POINT out. I STARTED THE post-grADUATE FOR THE SAKE OF BECOMING A teacher. During THESE YEARS I HAVE HAD THE OPPORTUNITY OF HELPING PROFESSORS ON LAB subjects, AND I HAVE ENJOYED IT A lot. But, BESIDES ANY CONCRETE CONCEPT I TAUGHT STUDENTS (which I HOPE THEY understood), RESEARCH HAS TAUGHT ME TO ASK MYSELF FOR THE WHY OF THE things. That is, TO ZOOM OUT FROM THE CONCRETE TOPIC WE WERE WORKING on, AND START ASKING MYSELF QUESTIONS like: Why ARE WE WORKING ON this? Are WE THE fiRST ONES WORKING ON this? What DO THE OTHERS do, WHAT DO THEY ADD TO THE topic? What INTERACTIONS CAN BE DONE FROM OUR approaches? Can WE fiND NEW WAYS FOR COLLABORATING AND START NEW APPROACHES together? This VALUABLE WAY OF THINKING WILL BE VERY USEFUL TO ME FOR THE REST OF MY life, WHATEVER I DO FOR living. Thus, THANKS FOR that. The SECOND MAYOR POINT IS RELATED TO PUTTING MY BODY IN ANOTHER PART OF THE globe. Although Madrid IS A NICE PLACE FOR MEETING PEOPLE FROM OTHER countries, LEARN ABOUT THEIR culture, WHAT DO THEY like/dislike, THE WAY THEY think, etc., THE TRUTH IS I DID NOT fiND MYSELF IN SUCH AS MUCH INTERACTION AS I WOULD HAVE wanted. Research HAS ALLOWED ME TO FULLY EXPERIENCE THE NOTION OF THE Global Village, VIA CONFERENCES AND SUMMER SCHOOLS WHERE I INTERACTED WITH PEOPLE FROM NEARLY everywhere. Also, IT ALLOWED ME TO LIVE IN Ireland FOR NINE months, IMMERSING MYSELF COMPLETELY IN THE DAILY LIFE OF THE country, THE Cork CITY AND THE Cork ConstrAINT Computation Centre (4C) I WAS WORKING for. I WANT TO SAY THAT THIS HAS BEEN ONE OF THE BEST EXPERIENCES IN MY life, AND IT ALLOWS ME TO LINK WITH THE fiNAL IDEA I AM TRYING TO express. When YOU KNOW YOU LIKE A, YOU DO it, YOU ENJOY IT AND YOU ARE happy. Good. But, THERE ARE OTHER THINGS B, C, D, etc., THAT YOU WOULD ALSO like, AND YOU DO NOT EVEN KNOW them. Moreover, YOU WILL PROBABLY NOT BE AVAILABLE TO DISCOVER THEM BY yourself. It WAS RESEARCH WHICH PLACED ME IN A FOREIGN GROUP AND country, MAKING ME DISCOVERING THAT THIS WAS AN EXPERIENCE REALLY MAKING ME happy. Thus, THANKS FOR that. By NOW I HAVE FOCUSED IN THE THINGS I WANT TO SAY THANKS for. However, IT WAS NOT RESEARCH, BUT CONCRETE people, THE ONES MAKING THESE THINGS possible. I WOULD LIKE TO START ACKNOWLEDGING Paco. WE CAN SAY THAT MY post-grADUATE STORY STARTED WITH THE SUBJECT Computability AND Complexity, WHERE HE WAS MY professor. I FOUND AMAZING THE MATERIAL HE proposed, BUT SPECIALLY THE WAY HE MADE US think/reason ABOUT it. Further, I DISCOVERED that, BESIDES A GREAT pro- fessor, HE IS ALSO A GREAT RESEARCHER (head OF THE GPD). I WANT TO THANK HIM FOR OFFERING ME JOINING THE group, FOR TRUSTING IN MY CAPABILITIES and, IN summary, FOR GIVING ME THE OPPORTUNITY FOR DOING THE MASTER AND THE thesis. Finally, I WANT TO THANK HIM for, EVEN WITH SUCH A TIGHT agenda, ALWAYS BEING IN CHARGE OF ENSURING THAT EVERYTHING WAS OK WITH me. I MET Fernando WHEN I JOINED THE GPD, AND HE HAS BEEN MY ADVISOR DURING ALL THESE post-grADUATE years. As WE HAVE HAD A DAILY RELATIONSHIP SINCE then, I APPRECIATE HIM SO much, BOTH FROM A PERSONAL AND A PROFESSIONAL POINT OF view, SO I fiND DIffiCULT NOT TO MIX THE TWO THINGS now. I WANT TO THANK HIM FOR intro- DUCING ME TO THE KNOWLEDGE AREA OF ConstrAINT Functional Logic ProgrAMMING OVER Finite Domains. He HAS GUIDED ME DURING THE ENTIRE RESEARCH process, AT ANY point, AT ANY moment. He HAS SHOWN ME HOW TO CARRY OUT A project, AND HOW TO ACCOMPLISH IT ON TIME AND QUALITY BY APPLYING patience, COMMON SENSE AND HARD work. I WANT TO THANK HIM FOR HIS POSITIVE ATtitude, HIS ADVICES AND FOR BEING A RIGHT person. During ALL THESE years, AND SPECIALLY WHEN THE THINGS TURNED MORE DIfficult, I HAVE FELT HIS CONfiDENCE ON ME TO OVERCOME THE DIfficul- TIES AND ACHIEVE THE PROPOSED goals. In summary, I FEEL VERY HAPPY OF HAVING HAD THE OPPORTUNITY OF WORKING WITH him. All I SAID FOR Fernando IS ALSO APPLICABLE TO Teresa, WHO I MET AS WELL WHEN I JOINED THE GPD. Although SHE RETIRED A COUPLE OF YEARS ago, SHE HAS BEEN CRUCIAL IN THE DEVELOPMENT OF MY MASTER AND IN THE EARLY STAGES OF THIS thesis. I WANT TO THANK HER FOR TEACHING ME THE BASICS OF researching, GUIDING ME TO BRIDGE THE GAP BETWEEN under-grADUATE AND post-graduate. Looking BACK now, I AM TOTALLY SURE that, WITHOUT HER ADVISES AND support, I WOULD HAVE NOT ACHIEVED it. Enrique, Adrián, Manu, Juan, Carlos, Roberto, Pablo, Miky, Edison, Kike, Diego, J. Fran, Javier, Alaeddin, Daniele, TAMA AND VicenzO HAVE BEEN MY col- LEAGUES AT THE LAB Office. I WANT TO THANK THEM FOR THE GREAT ATMOSPHERE WE HAVE HAD ALL THIS time, FOR BEING SUCH GREAT GUYS AND FOR TURNING HARD DAYS INTO BETTER ones. I MET Barry IN THE CP Summer School OF 2008, WHERE HE WAS THE PROFESSOR OF SOME lectures. I ALSO MET THERE PhD STUDENTS EITHER DOING THEIR THESIS AT THE 4C, OR GOING THERE AS visitors. All OF THEM TOLD ME GOOD THINGS ABOUT THE group, THE RESEARCH TOPICS THEY WERE WORKING AT AND THE WAY THEY WERE treated. Thus, AS THE PhD SCHOLARSHIP I HAD AT THE GPD ALLOWED ME FOR MOVING ABROAD AS A visitor, I APPLIED TO THE 4C. I HAVE VISITED THEM IN 2011 AND 2013. In BOTH cases, Barry HAS BEEN MY supervisor. I WANT TO THANK HIM FOR ALLOWING ME TO JOIN ONE OF THE RESEARCH LINES OF THE group. For me, IT HAS BEEN AMAZING TO BE ADVISED BY him, TO JUMP INTO A NEW RESEARCH TOPIC AND TO BE ABLE TO MAKE SOME progress, AS TO CONTRIBUTE something. Besides that, I HEREBY CONfiRM ALL THE GOOD feed- BACK I RECEIVED FROM THE 4C, AND I WOULD ENCOURAGE OTHER PhD STUDENTS TO VISIT THE group, AS IT WAS SUCH A GREAT EXPERIENCE TO me. In particular, BESIDES Barry, I ALSO WANT TO THANK TO ALL MY COLLEAGUES AT THE LAB Office, FOR TREATING ME incred- IBLY WELL AND MAKE ME FEEL AT home. Thanks TO Diarmuid, Milan, Alex, Barry, Luis, Yuri, Yulia, Vincent, Massimo, Georgiana, Óscar, Giovanni, Lars, Mohamed, Deepak AND Padraig. Finally, I WOULD LIKE TO ACKNOWLEDGE THIS THESIS TO ALL MY FAMILY AND friends, FOR MAKING ME A HAPPY person. In particular, I WOULD LIKE TO THANK MY parents, Pilar AND Antonio, FOR ALL THEIR LOVE AND support, AND MY sister, Alicia, FOR THE SAME reasons, AND ALSO FOR HELPING ME WITH THE START OF THIS SECTION :-) Contents AbstrACT .