From 3da80b055277dd03b0c15c20c1c64f8327ae30c4 Mon Sep 17 00:00:00 2001
From: Lucas <lucas@domain.invalid>
Date: Tue, 17 Mar 2020 10:47:04 +0000
Subject: [PATCH] [fun-gen] add Nova fractal

---
 fun-gen.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 47 insertions(+), 4 deletions(-)

diff --git a/fun-gen.c b/fun-gen.c
index 62cd5ef..91649fd 100644
--- a/fun-gen.c
+++ b/fun-gen.c
@@ -196,7 +196,8 @@ usage(void)
 	fprintf(stderr, "Usage:\n"
 	    "\t%s p-degree q-degree p-coefs q-coefs\n"
 	    "\t%s -h p-degree p-coefs\n"
-	    "\t%s -n p-degree p-coefs\n", p, p, p);
+	    "\t%s -N ra ia p-degree p-coefs\n"
+	    "\t%s -n p-degree p-coefs\n", p, p, p, p);
 	exit(1);
 }
 
@@ -276,6 +277,43 @@ do_halley(int argc, char *argv[])
 	poly_free(&q);
 }
 
+static void
+do_nova(int argc, char *argv[])
+{
+	struct poly f, df, p;
+	double complex a;
+	double ra, ia;
+	int i, j, f_degree;
+
+	if (argc < 3)
+		usage();
+
+	ra = parse_double(argv[0]);
+	ia = parse_double(argv[1]);
+	a = ra + I * ia;
+	argc -= 2; argv += 2;
+
+	f_degree = parse_integer(argv[0], 0, MAX_DEGREE);
+	if (argc != f_degree + 1 + 1)
+		usage();
+
+	poly_init(&f, f_degree, "f");
+	for (j = 0, i = 1 + f.degree;
+	    i > 0;
+	    i--, j++)
+		f.coefs[j] = parse_double(argv[i]);
+
+	poly_derivate(f, &df, "q");
+	poly_init(&p, f_degree, "p");
+	for (i = 0; i <= f.degree; i++)
+		p.coefs[i] = (i == 0 ? 0.0 : df.coefs[i - 1]) - a * f.coefs[i];
+
+	print_funs(p, df);
+	poly_free(&f);
+	poly_free(&df);
+	poly_free(&p);
+}
+
 static void
 do_newton(int argc, char *argv[])
 {
@@ -309,14 +347,17 @@ do_newton(int argc, char *argv[])
 int
 main(int argc, char *argv[])
 {
-	int ch, hflag, nflag;
+	int ch, hflag, Nflag, nflag;
 
-	hflag = nflag = 0;
-	while ((ch = getopt(argc, argv, "hn")) != -1)
+	hflag = Nflag = nflag = 0;
+	while ((ch = getopt(argc, argv, "hNn")) != -1)
 		switch (ch) {
 		case 'h':
 			hflag = 1;
 			break;
+		case 'N':
+			Nflag = 1;
+			break;
 		case 'n':
 			nflag = 1;
 			break;
@@ -328,6 +369,8 @@ main(int argc, char *argv[])
 
 	if (hflag)
 		do_halley(argc, argv);
+	else if (Nflag)
+		do_nova(argc, argv);
 	else if (nflag)
 		do_newton(argc, argv);
 	else