chore(math): initialize pallas-math crate (#474)

Cargo.toml

@@ -14,6 +14,7 @@ members = [
   "pallas-utxorpc",
   "pallas-hardano",
   "pallas-wallet",
+  "pallas-math",
   "pallas",
   "examples/block-download",
   "examples/block-decode",

README.md

@@ -53,6 +53,7 @@ As already explained, _Pallas_ aims at being an expanding set of components. The
 | ------------------------------- | -------------------------------------------------- |
 | [pallas-crypto](/pallas-crypto) | Shared Cryptographic primitives                    |
 | [pallas-codec](/pallas-codec)   | Shared CBOR encoding / decoding using minicbor lib |
+| [pallas-math](/pallas-math)     | Shared mathematics functions                       |
 
 ## Etymology
 

pallas-math/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "pallas-math"
+description = "Mathematics functions for Cardano"
+version = "0.27.0"
+edition = "2021"
+repository = "https://github.com/txpipe/pallas"
+homepage = "https://github.com/txpipe/pallas"
+documentation = "https://docs.rs/pallas-math"
+license = "Apache-2.0"
+readme = "README.md"
+authors = ["Andrew Westberg <andrewwestberg@gmail.com>"]
+
+[dependencies]
+rug = "1.24.1"
+
+[dev-dependencies]
+quickcheck = "1.0"
+quickcheck_macros = "1.0"
+rand = "0.8"

pallas-math/README.md

@@ -0,0 +1,14 @@
+# Pallas Math
+
+Crate with all the mathematics functions to support Cardano protocol:
+
+- [] lncf - Approximate `ln(1+x)` for `x in 0..infinty`.
+- [] cf - Compute continued fraction using max steps or bounded list of a/b factors.
+- [] bound - Simple way to find integer powers that bound x.
+- [] contract - Bisect bounds to find the smallest integer power such that `factor^n<=x<factor^(n+1)`.
+- [] find_e - find n with `e^n<=x<e^(n+1)`.
+- [] ln - Compute natural logarithm via continued fraction, first splitting integral part and then using continued fractions approximation for `ln(1+x)`.
+- [] taylor_exp - Compute `exp(x)` using Taylor expansion.
+- [] taylor_exp_cmp - Efficient way to compare the result of the Taylor expansion of the exponential function to a threshold value.
+- ...
+- ...

pallas-math/src/lib.rs

@@ -0,0 +1 @@
+pub mod math;

pallas-math/src/math.rs

@@ -0,0 +1,17 @@
+/*!
+# Cardano Math functions
+*/
+
+pub fn add(a: i32, b: i32) -> i32 {
+    a + b
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_add() {
+        assert_eq!(add(1, 2), 3);
+    }
+}