Better (?) exec_on_roots

adamant-pwn · adamant-pwn · commit 23aabb142229 · 2025-04-24T21:56:10.000+02:00
diff --git a/cp-algo/math/cvector.hpp b/cp-algo/math/cvector.hpp
@@ -93,8 +93,8 @@ namespace cp_algo::math::fft {
             point cur;
             point arg = root(n, 1);
             for(size_t i = 0; i < m; i++) {
-                if(i % 32 == 0 || n < pre_roots) {
-                    cur = root(n, i);
+                if(i % 32 == 0) {
+                    cur = root(n / 32, i / 32);
                 } else {
                     cur *= arg;
                 }
@@ -207,7 +207,7 @@ namespace cp_algo::math::fft {
             }
             checkpoint("fft");
         }
-        static constexpr size_t pre_roots = 1 << 14;
+        static constexpr size_t pre_roots = 1 << 15;
         static constexpr size_t pre_evals = 1 << 16;
         static constexpr std::array<point, pre_roots> roots = []() {
             std::array<point, pre_roots> res = {};

Original file line number	Diff line number	Diff line change
`@@ -93,8 +93,8 @@ namespace cp_algo::math::fft {`
`93`	`93`	`point cur;`
`94`	`94`	`point arg = root(n, 1);`
`95`	`95`	`for(size_t i = 0; i < m; i++) {`
`96`		`- if(i % 32 == 0 \|\| n < pre_roots) {`
`97`		`- cur = root(n, i);`
	`96`	`+ if(i % 32 == 0) {`
	`97`	`+ cur = root(n / 32, i / 32);`
`98`	`98`	`} else {`
`99`	`99`	`cur *= arg;`
`100`	`100`	`}`
`@@ -207,7 +207,7 @@ namespace cp_algo::math::fft {`
`207`	`207`	`}`
`208`	`208`	`checkpoint("fft");`
`209`	`209`	`}`
`210`		`- static constexpr size_t pre_roots = 1 << 14;`
	`210`	`+ static constexpr size_t pre_roots = 1 << 15;`
`211`	`211`	`static constexpr size_t pre_evals = 1 << 16;`
`212`	`212`	`static constexpr std::array<point, pre_roots> roots = []() {`
`213`	`213`	`std::array<point, pre_roots> res = {};`