Reference · Math

math.exp

math.exp(num) -> float

What it does

e raised to the power of the number, as a float, as Python's math.exp. It is the inverse of math.log: math.exp(math.log(x)) is x, give or take the last digit.

Examples

print(math.exp(0), math.exp(1), math.exp(-1))print(math.exp(10), math.exp(math.log(10)))

1.0 2.718281828459045 0.3678794411714423322026.465794806718 10.000000000000002

Edge cases

• A large negative number gives 0.0: underflow is not an error.
• 709 is about the largest input that fits a float (about 8.2 × 10³⁰⁷); 710 is a range error.
• -inf gives 0.0, inf gives inf, NaN gives NaN.
• For math.exp(x) - 1 with a tiny x, math.expm1 keeps the digits that the subtraction loses.

print(math.exp(-1000), math.isfinite(math.exp(709)))print(math.exp(-math.inf), math.exp(math.inf), math.exp(math.nan))print(math.exp(1e-10) - 1, math.expm1(1e-10))

0.0 true0.0 inf NaN0.0000000001000000082740371 0.000000000100000000005

Errors

An input whose result is past the largest float is a runtime error (a range error), not an error value: it stops the request, and ?? does not catch it. A value that is not a number is a runtime error too; a decimal is converted first with float.

print(math.exp(710))

line 1: `math.exp`: math range error (710)

print(math.exp(null))

line 1: `math.exp` expects a number as argument 1, got null

Chaining

In a pipeline the number comes first. For a whole list, vec.exp does the same in one call:

let rate = 0.05print(rate * 10 | math.exp)print([0, 1, 2] | map(math.exp), vec.exp([0, 1, 2]))

1.6487212707001282[1.0, 2.718281828459045, 7.38905609893065] [1.0, 2.718281828459045, 7.38905609893065]

See also

math.log, math.expm1, math.exp2, math.pow, vec.exp

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