Congratulations!

SoilVision Systems Ltd. would like to extend our congratulations to Bob Nelson of PDESolutions Inc. on 31 years of finite element development. His focused work on the FlexPDE finite element solver has resulted in a unique product which forms an integral part of the SoilVision Systems Ltd. geotechnical product line. His implementation of advanced features such as automatic mesh generation and refinement, automatic timestep refinement, and moving meshes allow application of cutting edge numerical concepts to geotechnical engineering practice.







The development of the finite element code which eventually formed the FlexPDE product is an interesting journey in itself. A summary of some of the development milestones is as follows:

- In 1975 at Science Applications Inc., a library of matrix building subroutines (in FORTRAN) for differential operators was created, from which PDE solvers could be assembled. This was called DYLA (a pun for dial-a-code). It was used at SAI to do some moving-mesh combustion calculations (Gelinas and Doss).

- Then at Lawrence Livermore Lab in 1979 a program was written (in FORTRAN) that used a simple precursor to the FlexPDE scripting language. That program recognized a few pre-defined differential operators to build equations, but was otherwise very similar to FlexPDE.

- By 1990 the older system was re-written in Pascal to do the kind of symbolic equation processing that FlexPDE does. That effort became SPDE, which then became PDEase2.

- In 1996 and 1997, the PDEase2 product was included in the Macsyma mathematical software package (similar to MathCAD). The PDEase2 product was used in the Macsyma until the bancruptcy of the Macsyma Corporation. A new program was then written (in a custom language called BOP) to incorporate what had been learned in PDEase2, and 3D support was added. That was FlexPDE 1.

- In 2002, the software was converted to C++ and useful graphic libraries were added to make the software run independent of platform. That became FlexPDE 4.

Work continues on the FlexPDE product with the implementation of new features applicable to the geotechnical engineering community. More information regarding the FlexPDE product may be found from the PDE Solutions website.