An approach to verifying and debugging simulation models governed by ordinary differential equations: Part 1. Methodology for residual generation

For dynamic simulations to be credible, verification of the computer code must be an integral part of the modelling process. This two-part paper describes a novel approach to verification through program testing and debugging. In Part 1, a methodology is presented for detecting and isolating coding errors using back-to-back testing. Residuals are generated by comparing the output of two independent implementations, in response to identical inputs. The key feature of the methodology is that a specially modified observer is created using one of the implementations, so as to impose an error-dependent structure on these residuals. Each error can be associated with a fixed and known subspace, permitting errors to be isolated to specific equations in the code. It is shown that the geometric properties extend to multiple errors in either one of the two implementations. Copyright (C) 2003 John Wiley Sons, Ltd

Making the Most of Formal Specification Through Animation, Testing and Proof

AbstractThe use of formality in software development enables formal manipulation at the symbolic level and hence can yield new perspectives on the design which can be submitted to inspection and interactive or automatic analysis. We describe the experience of an industrial pilot project which undertook a formal development using VDM and B and employed a number of techniques for the analysis of the formal texts by animation, test case generation and proof. We assess the effectiveness of methodology and techniques adopted by measuring the introduction and detection of faults