Don't compile Legendre/Meissel/Lehmer/LMOS prime counts by default

Changes

@@ -49,6 +49,9 @@ Revision history for Perl module Math::Prime::Util
 
     - znorder uses Carmichael Lambda instead of Euler Phi.  Faster.
 
+    - Legendre, Meissel, Lehmer, and LMOS methods are no longer compiled by
+      default.  Add -DLEHMER if you really want access to them.
+
 
 0.35  2013-12-08
 

XS.xs

@@ -231,9 +231,6 @@ _XS_nth_prime(IN UV n)
   OUTPUT:
     RETVAL
 
-UV
-_XS_legendre_phi(IN UV x, IN UV a)
-
 SV*
 sieve_primes(IN UV low, IN UV high)
   ALIAS:
@@ -565,6 +562,9 @@ kronecker(IN SV* sva, IN SV* svb)
     _vcallsubn(aTHX_ G_SCALAR, "_generic_kronecker", 2);
     return; /* skip implicit PUTBACK */
 
+UV
+legendre_phi(IN UV n, IN UV a)
+
 double
 _XS_ExponentialIntegral(IN SV* x)
   ALIAS:

factor.c

@@ -755,7 +755,7 @@ int pplus1_factor(UV n, UV *factors, UV B1)
 {
   UV X1, X2, f;
   UV sqrtB1 = isqrt(B1);
-  MPUassert( (n >= 3) && ((n%2) != 0) , "bad n in pminus1_factor");
+  MPUassert( (n >= 3) && ((n%2) != 0) , "bad n in pplus1_factor");
 
   X1 =  7 % n;
   X2 = 11 % n;

lehmer.c

@@ -1,12 +1,10 @@
+#if defined(LEHMER) || defined(PRIMESIEVE_STANDALONE)
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <math.h>
 
-/* Below this size, just sieve (with table speedup). */
-#define SIEVE_LIMIT  60000000
-#define MAX_PHI_MEM  (896*1024*1024)
-
 /*****************************************************************************
  *
  * Lehmer prime counting utility.  Calculates pi(x), count of primes <= x.
@@ -58,6 +56,10 @@
  * Factorization", 2nd edition, 1994.
  */
 
+/* Below this size, just sieve (with table speedup). */
+#define SIEVE_LIMIT  60000000
+#define MAX_PHI_MEM  (896*1024*1024)
+
 static int const verbose = 0;
 #define STAGE_TIMING 0
 
@@ -844,35 +846,6 @@ UV _XS_LMOS_pi(UV n)
   return sum;
 }
 
-static const unsigned char primes_small[] =
-  {0,2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97,
-   101,103,107,109,113,127,131,137,139,149,151,157,163,167,173,179,181,191};
-#define NPRIMES_SMALL (sizeof(primes_small)/sizeof(primes_small[0]))
-
-UV _XS_legendre_phi(UV x, UV a) {
-  phitableinit();
-  /* For small values, calculate directly */
-  if (a <= PHIC) return tablephi(x, a);
-  /* For large values, do our non-recursive phi */
-  if (a >= NPRIMES_SMALL) return phi(x,a);
-  /* Otherwise, recurse */
-  {
-    UV i, sum = tablephi(x, PHIC);
-    for (i = PHIC+1; i <= a; i++) {
-      uint32_t p = primes_small[i];
-      UV xp = x/p;
-      if (xp < p) {
-        while (x < primes_small[a])
-          a--;
-        return (sum - a + i - 1);
-      }
-      sum -= _XS_legendre_phi(xp, i-1);
-    }
-    return sum;
-  }
-}
-
-
 #ifdef PRIMESIEVE_STANDALONE
 int main(int argc, char *argv[])
 {
@@ -907,3 +880,13 @@ int main(int argc, char *argv[])
   return(0);
 }
 #endif
+
+#else
+
+#include "lehmer.h"
+UV _XS_LMOS_pi(UV n)            { croak("Not compiled with Lehmer support"); }
+UV _XS_lehmer_pi(UV n)          { croak("Not compiled with Lehmer support"); }
+UV _XS_meissel_pi(UV n)         { croak("Not compiled with Lehmer support"); }
+UV _XS_legendre_pi(UV n)        { croak("Not compiled with Lehmer support"); }
+
+#endif

lehmer.h

@@ -8,6 +8,4 @@ extern UV _XS_meissel_pi(UV n);
 extern UV _XS_lehmer_pi(UV n);
 extern UV _XS_LMOS_pi(UV n);
 
-extern UV _XS_legendre_phi(UV x, UV a);
-
 #endif

lmo.c

@@ -259,6 +259,30 @@ static UV mapes(UV x, uint32 a)
   return (UV) val;
 }
 
+/* TODO: This is pretty simplistic. */
+UV legendre_phi(UV x, UV a) {
+  UV i, c = (a > 7) ? 7 : a;
+  UV sum = mapes(x, c);
+  if (a > c) {
+    UV p  = _XS_nth_prime(c);
+    UV pa = _XS_nth_prime(a);
+    for (i = c+1; i <= a; i++) {
+      p = _XS_next_prime(p);
+      UV xp = x/p;
+      if (xp < p) {
+        while (x < pa) {
+          a--;
+          pa = _XS_prev_prime(pa);
+        }
+        return (sum - a + i - 1);
+      }
+      sum -= legendre_phi(xp, i-1);
+    }
+  }
+  return sum;
+}
+
+
 typedef struct {
   sword_t  *sieve;                 /* segment bit mask */
   uint8    *word_count;            /* bit count in each 64-bit word */

lmo.h

@@ -5,4 +5,6 @@
 
 extern UV _XS_LMO_pi(UV n);
 
+extern UV legendre_phi(UV n, UV a);
+
 #endif

sieve.h

@@ -111,10 +111,7 @@ static UV prev_prime_in_sieve(const unsigned char* sieve, UV p) {
     UV d_ = p/30; \
     UV s_, mask_ = 2; \
     UV lastd_ = l_/30; \
-    if (get_prime_cache(l_, &sieve_) < l_) { \
-      release_prime_cache(sieve_); \
-      croak("Could not generate sieve for %"UVuf, l_); \
-    } \
+    get_prime_cache(l_, &sieve_); \
     s_ = sieve_[d_]; \
     if (p <= 5) { \
       p = (p <= 2) ? 2 : (p <= 3) ? 3 : 5; \

t/13-primecount.t

@@ -87,7 +87,7 @@ plan tests => 0 + 1
                 + $use64 * 3 * scalar(keys %pivals64)
                 + scalar(keys %intervals)
                 + 1
-                + 8 + 2*$extra; # prime count specific methods
+                + 4 + 2*$extra; # prime count specific methods
 
 ok( eval { prime_count(13); 1; }, "prime_count in void context");
 
@@ -156,14 +156,14 @@ sub parse_range {
 
 # Make sure each specific algorithm isn't broken.
 SKIP: {
-  skip "Not XS -- skipping direct primecount tests", 6 unless $isxs;
+  skip "Not XS -- skipping direct primecount tests", 2 unless $isxs;
   # This has to be above SIEVE_LIMIT in lehmer.c and lmo.c or nothing happens.
-  is(Math::Prime::Util::_XS_lehmer_pi  (66123456), 3903023, "XS Lehmer count");
-  is(Math::Prime::Util::_XS_meissel_pi (66123456), 3903023, "XS Meissel count");
-  is(Math::Prime::Util::_XS_legendre_pi(66123456), 3903023,"XS Legendre count");
-  is(Math::Prime::Util::_XS_LMOS_pi    (66123456), 3903023, "XS LMOS count");
-  is(Math::Prime::Util::_XS_LMO_pi     (66123456), 3903023, "XS LMO count");
-  is(Math::Prime::Util::_XS_prime_count(66123456), 3903023, "XS sieve count");
+  #is(Math::Prime::Util::_XS_lehmer_pi  (66123456),3903023,"XS Lehmer count");
+  #is(Math::Prime::Util::_XS_meissel_pi (66123456),3903023,"XS Meissel count");
+  #is(Math::Prime::Util::_XS_legendre_pi(66123456),3903023,"XS Legendre count");
+  #is(Math::Prime::Util::_XS_LMOS_pi    (66123456),3903023,"XS LMOS count");
+  is(Math::Prime::Util::_XS_LMO_pi     (66123456), 3903023,"XS LMO count");
+  is(Math::Prime::Util::_XS_prime_count(66123456), 3903023,"XS sieve count");
 }
 is(Math::Prime::Util::PP::_lehmer_pi   (1456789), 111119, "PP Lehmer count");
 is(Math::Prime::Util::PP::_sieve_prime_count(1456789), 111119, "PP sieve count");

xt/legendre_phi.t

@@ -22,7 +22,7 @@ foreach my $a (0 .. $sqrtx+1) {
   if ($a > $pcsqrtx) {
     is ( $expect, $pcx - $a + 1, "sieved phi($x,$a) = Pi($x) - $a + 1" );
   }
-  my $phixa = Math::Prime::Util::_XS_legendre_phi($x, $a);
+  my $phixa = Math::Prime::Util::legendre_phi($x, $a);
   is( $phixa, $expect, "Legendre phi($x,$a) = $expect" );
 }
 done_testing();