Split out inverse.h

Author: Chillee

content/numerical/PolyBase.h

@@ -44,11 +44,4 @@ poly operator*(poly a, const num b) {
 		poly c = a; \
 		return c o##= b; \
 	}
-OP(*, *=) OP(+, +=) OP(-, -=);
-poly modK(poly a, int k) { return {a.begin(), a.begin() + min(k, sz(a))}; }
-poly inverse(poly A) {
-	poly B = poly({num(1) / A[0]});
-	while (sz(B) < sz(A))
-		B = modK(B * (poly({num(2)}) - modK(A, 2*sz(B)) * B), 2 * sz(B));
-	return modK(B, sz(A));
-}
+OP(*, *=) OP(+, +=) OP(-, -=);

content/numerical/PolyInverse.h

@@ -0,0 +1,16 @@
+/**
+ * Author: chilli, Andrew He, Adamant
+ * Date: 2019-04-27
+ * Description: A FFT based Polynomial class.
+ */
+#pragma once
+
+#include "PolyBase.h"
+
+poly modK(poly a, int k) { return {a.begin(), a.begin() + min(k, sz(a))}; }
+poly inverse(poly A) {
+	poly B = poly({num(1) / A[0]});
+	while (sz(B) < sz(A))
+		B = modK(B * (poly({num(2)}) - modK(A, 2*sz(B)) * B), 2 * sz(B));
+	return modK(B, sz(A));
+}

content/numerical/PolyLogExp.h

@@ -6,6 +6,7 @@
 #pragma once
 
 #include "PolyBase.h"
+#include "PolyInverse.h"
 #include "PolyIntegDeriv.h"
 
 poly log(poly a) {

content/numerical/PolyPow.h

@@ -19,5 +19,5 @@ poly pow(poly a, ll m) {
 	a.resize(n);
 	auto res =  exp(log(a) * num(m)) * (j ^ m);
 	res.insert(res.begin(), p*m, 0);
-	return modK(res, n);
+	return {res.begin(), res.begin()+n};
 }

fuzz-tests/numerical/Polynomial.cpp

@@ -537,7 +537,7 @@ template <class A, class B> void testPow(string name, A f1, B f2, int mxSz = 5,
     }
     cout << name + " tests passed!" << endl;
     auto a = genVec((rand() % mxSz) + 1);
-    int p = mxSz;
+    int p = mxSz/2;
     {
         timeit x("mine");
         for (int it = 0; it < NUMITERS; it++) {
@@ -612,18 +612,18 @@ signed main() {
     ios::sync_with_stdio(0);
     cin.tie(0);
     int SZ = 100000;
-    testBinary("sub", mine::operator-, MIT::operator-, SZ);
-    testBinary("add", mine::operator+, MIT::operator+, SZ);
-    testBinary("div", mine::operator/, MIT::operator/, SZ);
-    testBinary("mod", mine::operator%, MIT::operator%, SZ);
-    testUnary("inv", mine::inverse, MIT::inverse, SZ);
-    testUnary("derivative", mine::deriv, MIT::deriv, SZ);
-    testUnary("integral", mine::integr, MIT::integ, SZ);
-    testUnary("log", mine::log, MIT::log, SZ);
-    testUnary("exp", mine::exp, MIT::exp, SZ);
+    // testBinary("sub", mine::operator-, MIT::operator-, SZ);
+    // testBinary("add", mine::operator+, MIT::operator+, SZ);
+    // testBinary("div", mine::operator/, MIT::operator/, SZ);
+    // testBinary("mod", mine::operator%, MIT::operator%, SZ);
+    // testUnary("inv", mine::inverse, MIT::inverse, SZ);
+    // testUnary("derivative", mine::deriv, MIT::deriv, SZ);
+    // testUnary("integral", mine::integr, MIT::integ, SZ);
+    // testUnary("log", mine::log, MIT::log, SZ);
+    // testUnary("exp", mine::exp, MIT::exp, SZ);
     SZ = 10000;
     testPow("pow", mine::pow, MIT::pow, SZ, 5);
-    testEval("eval", mine::eval, MIT::eval, SZ);
-    testInterp("interp", mine::interp, MIT::interp, SZ);
+    // testEval("eval", mine::eval, MIT::eval, SZ);
+    // testInterp("interp", mine::interp, MIT::interp, SZ);
     return 0;
 }