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Function `std.math.exponential.expm1`

Calculates the value of the natural logarithm base (e) raised to the power of x, minus 1.


						
				real expm1
				(
				

				  real x
				

				) pure nothrow @nogc @trusted;
				

				

				double expm1
				(
				

				  double x
				

				) pure nothrow @nogc @safe;
				

				

				float expm1
				(
				

				  float x
				

				) pure nothrow @nogc @safe;

For very small x, expm1(x) is more accurate than exp(x)-1.

Special Values
x	e^x-1
±0.0	±0.0
+∞	+∞
-∞	-1.0
NAN	NAN

Example

import std.math.traits : isIdentical;
import std.math.operations : feqrel;

assert(isIdentical(expm1(0.0), 0.0));
assert(expm1(1.0).feqrel(1.71828) > 16);
assert(expm1(2.0).feqrel(6.3890) > 16);

Authors

Walter Bright, Don Clugston, Conversion of CEPHES math library to D by Iain Buclaw and David Nadlinger

License

Boost License 1.0.