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Getting started

Shoals is a Chelis library for financial calculations. You use its released package as a Reef dependency; there is no need to check out Shoals' source repository. Follow the Chelis install guide to install the toolchain.

Create a project, then download Shoals and the four packages it depends on from their GitHub releases. These downloads need no GitHub token:

Terminal window
chelisup install 0.22.1
chelis +0.22.1 reef init demo --module-prefix Demo --output demo
cd demo
chelis reef install --from-github chelis-lang/nautilus@v0.7.58
chelis reef install --from-github chelis-lang/coral@v0.7.52
chelis reef install --from-github chelis-lang/shoreleave@v0.1.6
chelis reef install --from-github chelis-lang/chelis-clarabel@v0.1.2
chelis reef install --from-github chelis-lang/shoals@v0.25.1

Add the Shoals dependency to the generated reef.toml:

[package]
compiler = "=0.22.1"


[dependencies]
shoals = { version = "=0.25.1" }

Then run chelis reef build. If GITHUB_TOKEN is set or the gh CLI is signed in, chelis reef build finds and downloads missing packages itself and the reef install lines are unnecessary; without either, it stops with remote discovery is unavailable ... GITHUB_TOKEN is not set. See Reef and packages for the project setup.

Begin with the pricing reference for its exported pricing functions, then read conventions for tensor inputs and random keys.

Price a call

Section titled “Price a call”

Shoals.Pricing.bs_call_scalar takes spot, strike, continuously compounded risk-free rate, volatility, and maturity in years, all as f32. It prices a European call on a non-dividend-paying underlying:

module Demo.Main
import Shoals.Pricing (bs_call_scalar)
px = bs_call_scalar(cast(100.0, f32), cast(100.0, f32), cast(0.05, f32), cast(0.2, f32), cast(1.0, f32))

Save it as src/main.ch in that project, replacing the starter module, then run chelis eval --file src/main.ch:

px = 10.450583