NTT multiplication: rewrite planner and improve comments

Cargo.toml

@@ -23,6 +23,7 @@ rand_core_0_9 = ["dep:rand_core_0_9"]
 rand_0_10 = ["rand_core_0_10", "dep:rand_0_10"]
 rand_core_0_10 = ["dep:rand_core_0_10"]
 serde = ["dep:serde"]
+bench-internals = []
 
 [package.metadata.docs.rs]
 features = ["std", "serde", "rand_0_10", "rand_0_9", "quickcheck", "arbitrary"]
@@ -47,6 +48,10 @@ required-features = ["rand_0_10"]
 harness = false
 name = "shootout-pidigits"
 
+[[bench]]
+name = "ntt_plan"
+required-features = ["bench-internals"]
+
 [dependencies]
 
 [dependencies.num-integer]

benches/ntt_plan.rs

@@ -0,0 +1,55 @@
+#![feature(test)]
+
+extern crate test;
+
+// Run with: cargo bench --bench ntt_plan --features bench-internals
+
+use num_bigint::__benchmark_ntt_plan_build;
+use test::{black_box, Bencher};
+
+macro_rules! ntt_plan_bench {
+    ($name:ident, $prime:expr, $exponent:expr) => {
+        #[bench]
+        fn $name(bencher: &mut Bencher) {
+            let min_len = 1usize << $exponent;
+            bencher.iter(|| black_box(__benchmark_ntt_plan_build::<$prime>(black_box(min_len))));
+        }
+    };
+}
+
+ntt_plan_bench!(p1_2_09, 1, 9);
+ntt_plan_bench!(p1_2_10, 1, 10);
+ntt_plan_bench!(p1_2_11, 1, 11);
+ntt_plan_bench!(p1_2_12, 1, 12);
+ntt_plan_bench!(p1_2_13, 1, 13);
+ntt_plan_bench!(p1_2_14, 1, 14);
+ntt_plan_bench!(p1_2_15, 1, 15);
+ntt_plan_bench!(p1_2_16, 1, 16);
+ntt_plan_bench!(p1_2_17, 1, 17);
+ntt_plan_bench!(p1_2_18, 1, 18);
+ntt_plan_bench!(p1_2_19, 1, 19);
+ntt_plan_bench!(p1_2_20, 1, 20);
+ntt_plan_bench!(p2_2_09, 2, 9);
+ntt_plan_bench!(p2_2_10, 2, 10);
+ntt_plan_bench!(p2_2_11, 2, 11);
+ntt_plan_bench!(p2_2_12, 2, 12);
+ntt_plan_bench!(p2_2_13, 2, 13);
+ntt_plan_bench!(p2_2_14, 2, 14);
+ntt_plan_bench!(p2_2_15, 2, 15);
+ntt_plan_bench!(p2_2_16, 2, 16);
+ntt_plan_bench!(p2_2_17, 2, 17);
+ntt_plan_bench!(p2_2_18, 2, 18);
+ntt_plan_bench!(p2_2_19, 2, 19);
+ntt_plan_bench!(p2_2_20, 2, 20);
+ntt_plan_bench!(p3_2_09, 3, 9);
+ntt_plan_bench!(p3_2_10, 3, 10);
+ntt_plan_bench!(p3_2_11, 3, 11);
+ntt_plan_bench!(p3_2_12, 3, 12);
+ntt_plan_bench!(p3_2_13, 3, 13);
+ntt_plan_bench!(p3_2_14, 3, 14);
+ntt_plan_bench!(p3_2_15, 3, 15);
+ntt_plan_bench!(p3_2_16, 3, 16);
+ntt_plan_bench!(p3_2_17, 3, 17);
+ntt_plan_bench!(p3_2_18, 3, 18);
+ntt_plan_bench!(p3_2_19, 3, 19);
+ntt_plan_bench!(p3_2_20, 3, 20);

src/biguint.rs

@@ -25,6 +25,12 @@ mod convert;
 mod iter;
 mod monty;
 mod ntt;
+
+#[cfg(feature = "bench-internals")]
+#[doc(hidden)]
+pub fn __benchmark_ntt_plan_build<const PRIME: usize>(min_len: usize) -> (usize, usize, usize) {
+    ntt::benchmark_plan_build::<PRIME>(min_len)
+}
 mod power;
 mod roots;
 mod serde;