Perform trial division for the first 180 primes on isprime function i…

…f argument has more than one limb
alpertron · May 6, 2020 · bdb489f · bdb489f
1 parent 6eb6209
commit bdb489f
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Showing 22 changed files with 121 additions and 101 deletions.
diff --git a/CONTFRAC.HTM b/CONTFRAC.HTM
diff --git a/CUAD.HTM b/CUAD.HTM
diff --git a/CUADMOD.HTM b/CUADMOD.HTM
diff --git a/ConsoleApplication1.vcxproj.user b/ConsoleApplication1.vcxproj.user
@@ -8,7 +8,7 @@
     <DebuggerFlavor>WindowsLocalDebugger</DebuggerFlavor>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
-    <LocalDebuggerCommandArguments>11*modinv(2,7)</LocalDebuggerCommandArguments>
+    <LocalDebuggerCommandArguments>11</LocalDebuggerCommandArguments>
     <DebuggerFlavor>WindowsLocalDebugger</DebuggerFlavor>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">

diff --git a/ECM.HTM b/ECM.HTM
diff --git a/ECMC.HTM b/ECMC.HTM
diff --git a/FACTPOL.HTM b/FACTPOL.HTM
diff --git a/FCUBES.HTM b/FCUBES.HTM
diff --git a/FRACCONT.HTM b/FRACCONT.HTM
diff --git a/FSQUARES.HTM b/FSQUARES.HTM
diff --git a/GAUSIANO.HTM b/GAUSIANO.HTM
diff --git a/GAUSSIAN.HTM b/GAUSSIAN.HTM
diff --git a/POLFACT.HTM b/POLFACT.HTM
diff --git a/QUAD.HTM b/QUAD.HTM
diff --git a/QUADMOD.HTM b/QUADMOD.HTM
diff --git a/SUMCUAD.HTM b/SUMCUAD.HTM
diff --git a/SUMCUBOS.HTM b/SUMCUBOS.HTM
diff --git a/bignbr.c b/bignbr.c
@@ -22,6 +22,7 @@ along with Alpertron Calculators.  If not, see <http://www.gnu.org/licenses/>.
 #include "factor.h"
 #include "expression.h"
 #include "skiptest.h"
+
 static BigInteger Temp, Temp2, Temp3, Base, Power, expon;
 static char ProcessExpon[MAX_LEN*BITS_PER_GROUP + 1000];
 static char primes[MAX_LEN*BITS_PER_GROUP + 1000];
@@ -33,6 +34,7 @@ extern int q[MAX_LEN];
 extern limb TestNbr[MAX_LEN];
 extern limb MontgomeryMultR1[MAX_LEN];
 int groupLen = 6;
+static int smallPrimes[SMALL_PRIMES_ARRLEN];
 #ifdef __EMSCRIPTEN__
 int percentageBPSW;
 #endif
@@ -1521,6 +1523,33 @@ static void Halve(limb *pValue)
   }
 }
 
+void initializeSmallPrimes(int* pSmallPrimes)
+{
+  int ctr, P;
+  if (*pSmallPrimes != 0)
+  {
+    return;
+  }
+  P = 3;
+  *pSmallPrimes++ = 2;
+  for (ctr = 1; ctr < SMALL_PRIMES_ARRLEN; ctr++)
+  {     // Loop that fills the SmallPrime array.
+    int Q;
+    *pSmallPrimes++ = P; /* Store prime */
+    do
+    {
+      P += 2;
+      for (Q = 3; Q * Q <= P; Q += 2)
+      { /* Check if P is prime */
+        if (P % Q == 0)
+        {
+          break;  /* Composite */
+        }
+      }
+    } while (Q * Q <= P);
+  }
+}
+
 // BPSW primality test:
 // 1) If the input number is 2-SPRP composite, indicate composite and go out.
 // 2) If number is perfect square, indicate it is composite and go out.
@@ -1561,6 +1590,22 @@ int BpswPrimalityTest(/*@in@*/BigInteger *pValue)
   {
     return 1;    // Number is even and different from 2. Indicate composite.
   }
+  if (nbrLimbs > 1)
+  {              // Check whether it is divisible by small number.
+    int primeIndex;
+    initializeSmallPrimes(smallPrimes);
+    for (primeIndex = 0; primeIndex < 180; primeIndex += 3)
+    {
+      int primeProd = smallPrimes[primeIndex] * smallPrimes[primeIndex+1] * smallPrimes[primeIndex+2];
+      int remainder = getRemainder(pValue, primeProd);
+      if (remainder % smallPrimes[primeIndex] == 0 ||
+        remainder % smallPrimes[primeIndex + 1] == 0 ||
+        remainder % smallPrimes[primeIndex + 2] == 0)
+      {
+        return 1;   // Number is divisible by small number. Indicate composite.
+      }
+    }
+  }
 #ifdef __EMSCRIPTEN__
 #ifdef FACTORIZATION_APP
   StepECM = 3;   // Show progress (in percentage) of BPSW primality test.

diff --git a/dilog.htm b/dilog.htm
diff --git a/expression.c b/expression.c
@@ -48,7 +48,6 @@ along with Alpertron Calculators.  If not, see <http://www.gnu.org/licenses/>.
 #define MAXIMUM_OPERATOR             18
 
 #define COMPUTE_NEXT_PRIME_SIEVE_SIZE 2000
-#define SMALL_PRIMES_ARRLEN           1229   // Number of primes less than 10000.
 
 static limb comprStackValues[COMPR_STACK_SIZE];
 static int comprStackOffset[PAREN_STACK_SIZE];
@@ -1073,33 +1072,6 @@ static enum eExprErr func(char *expr, BigInteger *ExpressionResult,
   return EXPR_OK;
 }
 
-static void initializeSmallPrimes(int* pSmallPrimes)
-{
-  int ctr, P;
-  if (*pSmallPrimes != 0)
-  {
-    return;
-  }
-  P = 3;
-  *pSmallPrimes++ = 2;
-  for (ctr = 1; ctr < SMALL_PRIMES_ARRLEN; ctr++)
-  {     // Loop that fills the SmallPrime array.
-    int Q;
-    *pSmallPrimes++ = P; /* Store prime */
-    do
-    {
-      P += 2;
-      for (Q = 3; Q * Q <= P; Q += 2)
-      { /* Check if P is prime */
-        if (P % Q == 0)
-        {
-          break;  /* Composite */
-        }
-      }
-    } while (Q * Q <= P);
-  }
-}
-
 static void generateSieve(int* pSmallPrimes, char* sieve, BigInteger* pArgument, int isNext)
 {
   int ctr;

diff --git a/expression.h b/expression.h
@@ -1,8 +1,8 @@
 #ifndef _EXPRESSION_H
 #define _EXPRESSION_H
 
-#define COPYRIGHT_SPANISH "Hecho por Darío Alpern. Actualizado el 4 de mayo de 2020."
-#define COPYRIGHT_ENGLISH "Written by Dario Alpern. Last updated on 4 May 2020."
+#define COPYRIGHT_SPANISH "Hecho por Darío Alpern. Actualizado el 6 de mayo de 2020."
+#define COPYRIGHT_ENGLISH "Written by Dario Alpern. Last updated on 6 May 2020."
 
 #ifdef __EMSCRIPTEN__
 int stamp(void);
@@ -43,6 +43,8 @@ enum eExprErr
   EXPR_OK = 0,
   EXPR_NOT_FOUND,
 };
+#define SMALL_PRIMES_ARRLEN           1229   // Number of primes less than 10000.
+
 #ifndef lang  
   extern int lang;
 #endif
@@ -57,5 +59,6 @@ void partition(int val, BigInteger *pResult);
 void factorial(BigInteger *result, int argument);
 void primorial(BigInteger *result, int argument);
 void textError(char * ptrOutput, enum eExprErr rc);
+void initializeSmallPrimes(int* pSmallPrimes);
 #else
 #endif
diff --git a/logdi.htm b/logdi.htm