timings for pidigits

TBR=rsc
OCL=32857
CL=32857

test/bench/pidigits.c

+/*
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in the
+    documentation and/or other materials provided with the distribution.
+
+    * Neither the name of "The Computer Language Benchmarks Game" nor the
+    name of "The Computer Language Shootout Benchmarks" nor the names of
+    its contributors may be used to endorse or promote products derived
+    from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/* The Computer Language Benchmarks Game
+  http://shootout.alioth.debian.org/
+
+  contributed by Paolo Bonzini & Sean Bartlett
+  modified by Michael Mellor
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <gmp.h>
+
+static mpz_t numer, accum, denom, tmp1, tmp2;
+
+static int extract_digit()
+{
+  if (mpz_cmp(numer, accum) > 0)
+    return -1;
+
+  /* Compute (numer * 3 + accum) / denom */
+  mpz_mul_2exp(tmp1, numer, 1);
+  mpz_add(tmp1, tmp1, numer);
+  mpz_add(tmp1, tmp1, accum);
+  mpz_fdiv_qr(tmp1, tmp2, tmp1, denom);
+
+  /* Now, if (numer * 4 + accum) % denom... */
+  mpz_add(tmp2, tmp2, numer);
+
+  /* ... is normalized, then the two divisions have the same result.  */
+  if (mpz_cmp(tmp2, denom) >= 0)
+    return -1;
+
+  return mpz_get_ui(tmp1);
+}
+
+static void next_term(unsigned int k)
+{
+  unsigned int y2 = k*2 + 1;
+
+  mpz_mul_2exp(tmp1, numer, 1);
+  mpz_add(accum, accum, tmp1);
+  mpz_mul_ui(accum, accum, y2);
+  mpz_mul_ui(numer, numer, k);
+  mpz_mul_ui(denom, denom, y2);
+}
+
+static void eliminate_digit(unsigned int d)
+{
+  mpz_submul_ui(accum, denom, d);
+  mpz_mul_ui(accum, accum, 10);
+  mpz_mul_ui(numer, numer, 10);
+}
+
+static void pidigits(unsigned int n)
+{
+  int d;
+  unsigned int i = 0, k = 0, m;
+  mpz_init(tmp1);
+  mpz_init(tmp2);
+  mpz_init_set_ui(numer, 1);
+  mpz_init_set_ui(accum, 0);
+  mpz_init_set_ui(denom, 1);
+
+  for(;;)
+  {
+    do {
+      k++;
+      next_term(k);
+      d = extract_digit();
+    } while(d == -1);
+
+    putchar(d + '0');
+
+    i++;
+    m = i%10;
+    if(m == 0)
+      printf("\t:%d\n", i);
+    if(i >= n)
+      break;
+    eliminate_digit(d);
+  }
+
+  if(m) {
+    m = 10 - m;
+    while(m--)
+      putchar(' ');
+    printf("\t:%d\n", n);
+  }
+}
+
+int main(int argc, char **argv)
+{
+  pidigits(argc > 1 ? atoi(argv[1]) : 27);
+  return 0;
+}

test/bench/pidigits.txt

+3141592653	:10
+5897932384	:20
+6264338   	:27

test/bench/timing.log

@@ -71,9 +71,9 @@ August 6, 2009
 
 k-nucleotide 5000000
 	gcc -O2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include k-nucleotide.c -lglib-2.0	k-nucleotide.c: 10.72u 0.01s 10.74r
-	gccgo -O2 k-nucleotide.go	22.69u 0.85s 24.09r
-	gc k-nucleotide	15.63u 0.26s 16.41r
-	gc_B k-nucleotide	17.22u 0.04s 17.28r
+	gccgo -O2 k-nucleotide.go	21.64u 0.83s 22.78r
+	gc k-nucleotide	16.08u 0.06s 16.50r
+	gc_B k-nucleotide	17.32u 0.02s 17.37r
 
 mandelbrot 5500
 	gcc -O2 mandelbrot.c	56.13u 0.02s 56.17r
@@ -86,3 +86,9 @@ meteor 16000
 	gccgo -O2 meteor-contest.go	0.12u 0.00s 0.14r
 	gc meteor-contest	0.24u 0.00s 0.26r
 	gc_B meteor-contest	0.23u 0.00s 0.24r
+
+pidigits 10000
+	gcc -O2 pidigits.c -lgmp	2.60u 0.00s 2.62r
+	gc pidigits	77.69u 0.14s 78.18r
+	gc_B pidigits	74.26u 0.18s 75.41r
+	gc_B pidigits	68.48u 0.20s 69.31r   # special case: no bounds checking in bignum

test/bench/timing.sh

@@ -111,9 +111,17 @@ meteor() {
 	run 'gc_B  meteor-contest' $O.out
 }
 
+pidigits() {
+	echo 'pidigits 10000'
+	run 'gcc -O2 pidigits.c -lgmp' a.out 10000
+#	run 'gccgo -O2 pidigits.go' a.out -n 10000  # uncomment when gccgo library updated
+	run 'gc pidigits' $O.out -n 10000
+	run 'gc_B  pidigits' $O.out -n 10000
+}
+
 case $# in
 0)
-	run="fasta revcom nbody binarytree fannkuch regexdna spectralnorm knucleotide mandelbrot meteor"
+	run="fasta revcom nbody binarytree fannkuch regexdna spectralnorm knucleotide mandelbrot meteor pidigits"
 	;;
 *)
 	run=$*