squiggle/packages/squiggle-lang/__tests__/Distributions/Scale_test.res
Quinn Dougherty 28cb6b9c88 Final cleanup, but typescript is still borked
Value: [1e-8 to 1e-6]
2022-05-06 15:09:00 -04:00

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open Jest
open Expect
open TestHelpers
describe("Scale logarithm", () => {
/* These tests may not be important, because scalelog isn't normalized
The first one may be failing for a number of reasons.
*/
Skip.test("mean of the base e scalar logarithm of an exponential(10)", () => {
let rate = 10.0
let scalelog = DistributionOperation.Constructors.scaleLogarithm(
~env,
mkExponential(rate),
MagicNumbers.Math.e,
)
let meanResult = E.R2.bind(DistributionOperation.Constructors.mean(~env), scalelog)
// expected value of log of exponential distribution.
let meanAnalytical = Js.Math.log(rate) +. 1.0
switch meanResult {
| Ok(meanValue) => meanValue->expect->toBeCloseTo(meanAnalytical)
| Error(err) => err->expect->toBe(DistributionTypes.OperationError(DivisionByZeroError))
}
})
let low = 10.0
let high = 100.0
let scalelog = DistributionOperation.Constructors.scaleLogarithm(~env, mkUniform(low, high), 2.0)
test("mean of the base 2 scalar logarithm of a uniform(10, 100)", () => {
//For uniform pdf `_ => 1 / (b - a)`, the expected value of log of uniform is `integral from a to b of x * log(1 / (b -a)) dx`
let meanResult = E.R2.bind(DistributionOperation.Constructors.mean(~env), scalelog)
let meanAnalytical = -.Js.Math.log2(high -. low) /. 2.0 *. (high ** 2.0 -. low ** 2.0) // -. Js.Math.log2(high -. low)
switch meanResult {
| Ok(meanValue) => meanValue->expect->toBeCloseTo(meanAnalytical)
| Error(err) => err->expect->toEqual(DistributionTypes.OperationError(NegativeInfinityError))
}
})
})