updated libquantum 0.1.0 source files

classic.c

@@ -0,0 +1,113 @@
+/* classic.c: Classic operations used in libquantum
+
+   Copyright 2003 Bjoern Butscher, Hendrik Weimer
+
+   This file is part of libquantum
+
+   libquantum is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published
+   by the Free Software Foundation; either version 2 of the License,
+   or (at your option) any later version.
+
+   libquantum 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
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with libquantum; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+   USA
+
+*/
+
+#include <math.h>
+
+/* Calculate A^B with A and B as integers */
+
+int
+quantum_ipow(int a, int b)
+{
+  int i;
+  int r=1;
+
+  for(i=0; i<b ;i++)
+    r*=a;
+
+  return r;
+}
+
+/* Calculate the greatest common divisor with Euclid's algorithm */
+
+int
+quantum_gcd(int u, int v)
+{
+  int r;
+
+  while(v)
+    {
+      r = u % v;
+      u = v;
+      v = r;
+    }
+  return u;
+}
+
+/* Fractional approximation of a decimal value */
+
+void
+quantum_frac_approx(int *a, int *b, int width)
+{
+  float f = (float) *a / *b;
+  float g=f;
+  int i, num2=0, den2=1, num1=1, den1=0, num=0, den=0;
+ 
+  do
+    {
+      i = (int) (g+0.000005);
+      
+      g -= i-0.000005;
+      g = 1.0/g;
+
+      if (i * den1 + den2 > 1<<width)
+	break;
+
+      num = i * num1 + num2;
+      den = i * den1 + den2;
+
+      num2 = num1;
+      den2 = den1;
+      num1 = num;
+      den1 = den;
+
+    } while(fabsf(((float) num / den) - f) > 1.0 / (2 * (1 << width)));
+  
+  *a = num;
+  *b = den;
+
+  return;
+}
+
+/* Calculates the number of qubits required to store N */
+
+int
+quantum_getwidth(int n)
+{
+  int i;
+  
+  for(i=1; 1<<i<n; i++);
+
+  return i;
+}
+
+/* Calculate the inverse modulus of N and C */
+
+int
+quantum_inverse_mod(int n, int c)
+{
+  int i;
+
+  for(i=1; (i*c)%n!=1; i++);
+
+  return i;
+}