Development of WORHP began in 2006, performed by a small team of young scientists, in response to an ESA initiative in 2004 for developing a European NLP solver. This first development effort resulted in a FORTRAN77-based SQP solver with reverse communication and exploitation of sparse matrix structures.
This initial version has since then been rewritten in C and Fortran2003 and extended by more than 20 contributing young scientists, and turned into a state-of-the-art NLP solver.

Development has been supported by BMWi (German Federal Ministry of Economics and Technology) and the TEC-EC Control Division of ESA (through GSTP-4 and GSTP-5), who aim to create a European NLP solver as critical component of mission analysis and other tools, and by the EU commission, who try to reduce the environmental impact of air traffic through the Clean Sky initiative.

WORHP's initial years of development have been accompanied and influenced by our industrial partner Astos Solutions, who led most of these initial activities, provided important feedback about industrial demands and practices, and posed challenging optimization problems for WORHP.

The ownership and rights to WORHP lie with Steinbeis Forschungszentrum Optimierung, Steuerung und Regelung, under the direction of Prof. Dr. Christof Büskens.

Development timeline

The WORHP development has been possible through funding during the following activities:

08-2006 09-2007 Sparse-NLP Solver Funded by BMWi grant 50JR0688, led by OHB Systems and in cooperation with Astos Solutions (formerly TTI).
06-2007 05-2010 Black-Box Optimierer Funded by BMWi grant 50RL0722, in cooperation with Astos Solutions.
12-2007 06-2010 eNLP Funded by ESA TEC-ECM (GSTP-4 G603-45EC "Non-Linear Programming Solver for Space Trajectory Optimization"), led by Astos Solutions and in cooperation with Skysoft (now GMV) and University of Coimbra.
12-2010 12-2011 eNLPext Funded by ESA TEC-ECM (GSTP-5 G517-045EC "Extension/Deployment of the European Mathematical NLP-solver"), led by Astos Solutions
04-2013 01-2015 Clean Sky ("AWACs") Funded by Clean Sky (JTI-CS-2012-3-SGO-03-020), together with Universität der Bundeswehr München, Technische Universität München and University of Southampton.