Bailey is perhaps best known as a co-author (with Peter Borwein and Simon Plouffe) of a 1997 paper that presented a new formula for π (pi), which had been discovered by Plouffe in 1995. This Bailey–Borwein–Plouffe formula permits one to calculate binary or hexadecimal digits of pi beginning at an arbitrary position, by means of a simple algorithm. Subsequently, Bailey and Richard Crandall showed that the existence of this and similar formulas has implications for the long-standing question of "normality"[2]—whether and why the digits of certain mathematical constants (including pi) appear "random" in a particular sense.
Bailey was a long-time collaborator with Jonathan Borwein (Peter's brother). They co-authored five books and over 80 technical papers on experimental mathematics.
Bailey also does research in numerical analysis and parallel computing. He has published studies on the fast Fourier transform (FFT), high-precision arithmetic, and the PSLQ algorithm (used for integer relation detection). He is a co-author of the NAS Benchmarks, which are used to assess and analyze the performance of parallel scientific computers. A "4-step" method of calculating the FFT is widely known as Bailey's FFT algorithm (Bailey himself credits it to W. M. Gentleman and G. Sande[3][4]).
He has also published articles in the area of mathematical finance, including a 2014 paper "Pseudo-mathematics and financial charlatanism," which emphasizes the dangers of statistical overfitting and other abuses of mathematics in the financial field.
Bailey is a member of the Church of Jesus Christ of Latter-day Saints. He has positioned himself as an advocate of the teaching of science and that accepting the conclusions of modern science is not incompatible with a religious view.[6]
with Jonathan Borwein: Mathematics by experiment: Plausible reasoning in the 21st century, A. K. Peters 2004, 2008 (with accompanying CD Experiments in Mathematics, 2006)
with Jonathan Borwein, Roland Girgensohn: Experimentation in mathematics: Computational paths to discovery, A. K. Peters 2004
with Robert F. Lucas, Samuel Williams (eds.): Performance tuning of scientific applications. Chapman & Hall/CRC Computational Science Series, CRC Press 2010, ISBN9781439815694.
^Gentleman, W.M.; Sande, G. (1966). "Fast Fourier Transforms—For Fun and Profit". AFIPS Conference Proceedings Volume 29. Fall Joint Computer Conference, November 7-10, 1966. San Francisco, California. pp. 563–578.
Bailey, D. H. (March 1989). "FFTS in external or hierarchical memory". Proceedings of the 1989 ACM/IEEE conference on Supercomputing – Supercomputing '89. Vol. 4. ACM Press. pp. 23–35. doi:10.1145/76263.76288. ISBN0-89791-341-8. S2CID52809390.