@@@ fltfmt mess

[mLib] / test / example / adhoc.c

diff --git a/test/example/adhoc.c b/test/example/adhoc.c
new file mode 100644 (file)
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+++ b/test/example/adhoc.c
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+/* -*-c-*-
+ *
+ * Demonstration of ad-doc testing
+ *
+ * (c) 2024 Straylight/Edgeware
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of the mLib utilities library.
+ *
+ * mLib is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU Library General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ *
+ * mLib is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
+ * License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with mLib.  If not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+ * USA.
+ */
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <limits.h>
+#include <stdio.h>
+
+#include "macros.h"
+#include "report.h"
+#include "tvec.h"
+#include "tvec-adhoc.h"
+#include "tvec-bench.h"
+#include "tvec-types.h"
+
+/*----- Main code ---------------------------------------------------------*/
+
+/* Stupid but traditional recursive Fibonacci. */
+static unsigned long recfib(unsigned n)
+  { return (n <= 1 ? n : recfib(n - 1) + recfib(n - 2)); }
+
+/* Slightly less stupid but still traditional iterative Fibonacci. */
+static unsigned long iterfib(unsigned n)
+{
+  unsigned long u, v, t;
+
+  for (u = 0, v = 1; n--; t = v, v = u, u += t);
+  return (u);
+}
+
+/* Sadly nontraditional intelligent Fibonacci. */
+static unsigned long expfib(unsigned n)
+{
+  unsigned long a, b, u, v, t;
+
+  /* We work in %$\Q(\phi)$%, where %$\phi^2 = \phi + 1$%.  I claim that
+   * %$\phi^k = F_k \phi + F_{k-1} \pmod f(\phi))$%.  Proof by induction:
+   * note that * %$F_{-1} = F_1 - F_0 = 1$%, so %$\phi^0 = 1 = {}$%
+   * %$F_0 \phi + F_{-1}$%; and %$\phi^{k+1} = F_k \phi^2 + {}$%
+   * %$F_{k-1} \phi = F_k (\phi + 1) + F_{k-1} \phi = (F_k + {}$%
+   * %$F_{k-1} \phi + F_k = F_{k+1} \phi + F_k$% as claimed.
+   *
+   * Now, notice that %$(a \phi + b) (c \phi + d) = a c \phi^2 + {}$%
+   * $%(a d + b c) \phi + b d = a c (\phi + 1) + (a d + b c) \phi + {}$%
+   * %$b d = (a c + a d + b c) \phi + (a c + b d)$%.  In particular,
+   * %$(u \phi + v)^2 \equiv (u^2 + 2 u v) \phi + (u^2 + v^2)$%.
+   */
+  a = 0, b = 1; u = 1, v = 0;
+  if (n)
+    for (;;) {
+      if (n%2) { t = a*u; a = t + a*v + b*u; b = t + b*v; }
+      n /= 2; if (!n) break;
+      t = u*u; u = t + 2*u*v; v = t + v*v;
+    }
+  return (a);
+}
+
+int main(int argc, char *argv[])
+{
+  struct tvec_state tvstate;
+  int argpos;
+  unsigned long i, a, b, t;
+
+  tvec_parseargs(argc, argv, &tvstate, &argpos, &tvec_adhocconfig);
+  if (argpos < argc) die(2, "no input files expected");
+  tvec_adhoc(&tvstate);
+
+#if (ULONG_MAX/65536 >> 16) >= 0xffffffff
+#  define FIBLIMIT 94               /* F_94 = 19740274219868223167 > 2^64 */
+#else
+#  define FIBLIMIT 48                  /* F_48 = 4807526976 > 2^32 */
+#endif
+
+  TVEC_TESTGROUP(&tvstate, "fib-test") {
+    for (i = 0, a = 0, b = 1; i < FIBLIMIT; i++, t = b, b = a, a += t)
+      TVEC_TEST(&tvstate) {
+       if (i < 40) TVEC_CLAIMEQ_UINT(&tvstate, a, recfib(i));
+       TVEC_CLAIMEQ_UINT(&tvstate, a, iterfib(i));
+       TVEC_CLAIMEQ_UINT(&tvstate, a, expfib(i));
+      }
+  }
+
+  TVEC_TESTGROUP(&tvstate, "fib-bench") {
+    TVEC_BENCHMARK_DECLS;
+
+    if (tvec_benchprep(&tvstate, &tvec_benchstate, 0)) break;
+
+    TVEC_BENCHMARK("recfib, n = 40", &tvstate, tvec_benchstate, BTU_OP, 1)
+      while (_bench_n--) ADMIRE(recfib(40));
+    TVEC_BENCHMARK("iterfib, n = " STR(FIBLIMIT),
+                  &tvstate, tvec_benchstate, BTU_OP, 1)
+      while (_bench_n--) ADMIRE(iterfib(FIBLIMIT));
+    TVEC_BENCHMARK("expfib, n = " STR(FIBLIMIT),
+                  &tvstate, tvec_benchstate, BTU_OP, 1)
+      while (_bench_n--) ADMIRE(expfib(FIBLIMIT));
+  }
+
+  return (tvec_end(&tvstate));
+}
+
+/*----- That's all, folks -------------------------------------------------*/