The calculation time is reduced by more then ten times by using a subset of the comprehensive data set consisting of only symmetrical arrays. It is further reduced by more than thirty times by calculating the Sherman–Morrison update for all the possible two-electrode combinations, which are then used to calculate the model resolution values for the four-electrode arrays. The calculation time is reduced by half by using the fact that arrays that are symmetrical about the center of the line produce identical changes in the model resolution values.

Recent improvements in computer GPU technology can reduce the calculation time by about seven times. A single-precision version of the ‘Compare R’ algorithm using a new ranking function reduces the calculation time by two to eight times while providing results similar to the double-precision version. Several techniques are proposed to reduce the calculation time for such survey lines. The optimization method faces practical limitations for 2-D survey lines with more than 60 electrodes where the number of possible arrays exceeds a million. The number of possible arrays (the comprehensive data set) increases with the fourth power of the number of electrodes. This method determines the optimum set of arrays by selecting those that give the maximum model resolution.

Previous studies show that optimized arrays generated using the ‘Compare R’ method have significantly better resolution than conventional arrays.

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