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Function `std.numeric.sumOfLog2s`

Compute the sum of binary logarithms of the input range r. The error of this method is much smaller than with a naive sum of log2.


						
				ElementType!Range sumOfLog2s(Range)
				(
				

				  Range r
				

				)
				

				if (isInputRange!Range && isFloatingPoint!(ElementType!Range));

Example

import std.math : isNaN;

writeln(sumOfLog2s(new double[0])); // 0
writeln(sumOfLog2s([0.0L])); // -real.infinity
writeln(sumOfLog2s([-0.0L])); // -real.infinity
writeln(sumOfLog2s([2.0L])); // 1
assert(sumOfLog2s([-2.0L]).isNaN());
assert(sumOfLog2s([real.nan]).isNaN());
assert(sumOfLog2s([-real.nan]).isNaN());
writeln(sumOfLog2s([real.infinity])); // real.infinity
assert(sumOfLog2s([-real.infinity]).isNaN());
writeln(sumOfLog2s([0.25, 0.25, 0.25, 0.125])); // -9

Authors

Andrei Alexandrescu, Don Clugston, Robert Jacques, Ilya Yaroshenko

License

Boost License 1.0.