The most versatile and frequently used method for numerically solving partial differential equations is that of approximation by difference equations. While the method has the advantages of conceptual simplicity, wide applicability, and ready suitability for digital computation, it also has the disadvantages of a predilection toward instability and of a frequent requirement for large storage capacity and excessive computing time. This Memorandum describes a modified approach that may be superior in some instances. Considering a particular equation, the usual difference approximation is replaced with a recurrence relation that clearly preserves such properties as boundedness and nonnegativity and that tends to the solution in the limit.
This report is part of the RAND Corporation Research memorandum series. The Research Memorandum was a product of the RAND Corporation from 1948 to 1973 that represented working papers meant to report current results of RAND research to appropriate audiences.
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