= John Rischard Rice
{c}
{title2=1934–2024}
= John R. Rice
{c}
{synonym}
<John Rischard Rice> was a <computer scientist> and mathematician whose work included numerical approximation, elliptic <partial differential equations> and mathematical software. Purdue's memorial identifies his full name and records that he led the development of the ELLPACK elliptic-problem software.<In Memoriam: Professor Emeritus John R. Rice by Eugene H. Spafford>[Opening identity paragraph and scientific-computing/ELLPACK paragraph]{ref}
His <algorithm selection> work separates a problem instance, its descriptive features, candidate algorithms and the performance criterion used to choose between them. The institutional technical-report record is dated 1975; the later chapter is dated 1976.<The Algorithm Selection Problem by John R. Rice>[Purdue technical report 75-152; later Advances in Computers15, pp65–118]{ref} Thus choosing an algorithm is itself a computational decision, not simply declaring one program universally best.
For an original example, suppose two candidates in an <algorithm portfolio> take $1$ and $5$ seconds, with relative errors $10^{-2}$ and $10^{-6}$ on one stipulated instance. If the rule is to minimize runtime subject to error at most $10^{-3}$, only the second candidate qualifies. Relaxing the tolerance to $10^{-1}$ makes the first candidate the faster admissible choice. The ranking changes because the stated task changes; the four values are chosen examples, not measured solver performance.
A real selector must obtain usable problem features and include selection overhead in its evaluation. Choosing after observing every candidate's completed result is a comparison bound, not automatically an implementable advance decision. This distinction connects numerical software to empirical tests of how its performance varies across inputs.
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