Introduce kernel-level LCM_INT

This is done using the gmp function mpz_lcm.
gap-system · Dec 12, 2017 · 64f783c · 64f783c
1 parent 9ae06ac
commit 64f783c
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Showing 2 changed files with 64 additions and 30 deletions.
diff --git a/lib/integer.gi b/lib/integer.gi
@@ -1078,13 +1078,7 @@ InstallGlobalFunction( IsPrimePowerInt,
 ##
 #F LcmInt( <m>, <n> ) . . . . . . . . . . least common multiple of integers
 ##
-InstallGlobalFunction(LcmInt,function ( n, m )
- if m = 0 and n = 0 then
- return 0;
- else
- return AbsInt( m / GcdInt( m, n ) * n );
- fi;
-end);
+InstallGlobalFunction(LcmInt, LCM_INT);
 
 
 #############################################################################

diff --git a/src/integer.c b/src/integer.c
@@ -2202,6 +2202,45 @@ Obj FuncGCD_INT ( Obj self, Obj opL, Obj opR )
  return GcdInt( opL, opR );
 }
 
+Obj LcmInt(Obj opL, Obj opR)
+{
+ UInt sizeL, sizeR;
+ fake_mpz_t mpzL, mpzR, mpzResult;
+ Obj result;
+
+ CHECK_INT(opL);
+ CHECK_INT(opR);
+
+ if (opL == INTOBJ_INT(0))
+ return AbsInt(opR);
+ if (opR == INTOBJ_INT(0))
+ return AbsInt(opL);
+
+ sizeL = SIZE_INT_OR_INTOBJ(opL);
+ sizeR = SIZE_INT_OR_INTOBJ(opR);
+
+ NEW_FAKEMPZ(mpzResult, sizeL + sizeR);
+ FAKEMPZ_GMPorINTOBJ(mpzL, opL);
+ FAKEMPZ_GMPorINTOBJ(mpzR, opR);
+
+ /* compute the gcd */
+ mpz_lcm(MPZ_FAKEMPZ(mpzResult), MPZ_FAKEMPZ(mpzL), MPZ_FAKEMPZ(mpzR));
+
+ /* convert result to GAP object and return it */
+ CHECK_FAKEMPZ(mpzResult);
+ CHECK_FAKEMPZ(mpzL);
+ CHECK_FAKEMPZ(mpzR);
+ result = GMPorINTOBJ_FAKEMPZ(mpzResult);
+ CHECK_INT(result);
+ return result;
+}
+
+Obj FuncLCM_INT(Obj self, Obj opL, Obj opR)
+{
+ REQUIRE_INT_ARG("LcmInt", "left", opL);
+ REQUIRE_INT_ARG("LcmInt", "right", opR);
+ return LcmInt(opL, opR);
+}
 
 /****************************************************************************
 **
@@ -2614,29 +2653,30 @@ static StructGVarFilt GVarFilts [] = {
 **
 *V GVarFuncs . . . . . . . . . . . . . . . . . . list of functions to export
 */
-static StructGVarFunc GVarFuncs [] = {
-
- GVAR_FUNC(QUO_INT, 2, "gmp1, gmp2"),
- GVAR_FUNC(ABS_INT, 1, "x"),
- GVAR_FUNC(SIGN_INT, 1, "x"),
- GVAR_FUNC(REM_INT, 2, "gmp1, gmp2"),
- GVAR_FUNC(GCD_INT, 2, "gmp1, gmp2"),
- GVAR_FUNC(PROD_INT_OBJ, 2, "gmp, obj"),
- GVAR_FUNC(POW_OBJ_INT, 2, "obj, gmp"),
- GVAR_FUNC(JACOBI_INT, 2, "n, m"),
- GVAR_FUNC(FACTORIAL_INT, 1, "n"),
- GVAR_FUNC(BINOMIAL_INT, 2, "n, k"),
- GVAR_FUNC(PVALUATION_INT, 2, "n, p"),
- GVAR_FUNC(POWERMODINT, 3, "base, exp, mod"),
- GVAR_FUNC(IS_PROBAB_PRIME_INT, 2, "n, reps"),
- GVAR_FUNC(INVMODINT, 2, "base, mod"),
- GVAR_FUNC(HexStringInt, 1, "gmp"),
- GVAR_FUNC(IntHexString, 1, "string"),
- GVAR_FUNC(Log2Int, 1, "gmp"),
- GVAR_FUNC(STRING_INT, 1, "gmp"),
- GVAR_FUNC(INT_STRING, 1, "string"),
- GVAR_FUNC(RandomIntegerMT, 2, "mtstr, nrbits"),
- { 0, 0, 0, 0, 0 }
+static StructGVarFunc GVarFuncs[] = {
+
+ GVAR_FUNC(QUO_INT, 2, "gmp1, gmp2"),
+ GVAR_FUNC(ABS_INT, 1, "x"),
+ GVAR_FUNC(SIGN_INT, 1, "x"),
+ GVAR_FUNC(REM_INT, 2, "gmp1, gmp2"),
+ GVAR_FUNC(GCD_INT, 2, "gmp1, gmp2"),
+ GVAR_FUNC(LCM_INT, 2, "gmp1, gmp2"),
+ GVAR_FUNC(PROD_INT_OBJ, 2, "gmp, obj"),
+ GVAR_FUNC(POW_OBJ_INT, 2, "obj, gmp"),
+ GVAR_FUNC(JACOBI_INT, 2, "n, m"),
+ GVAR_FUNC(FACTORIAL_INT, 1, "n"),
+ GVAR_FUNC(BINOMIAL_INT, 2, "n, k"),
+ GVAR_FUNC(PVALUATION_INT, 2, "n, p"),
+ GVAR_FUNC(POWERMODINT, 3, "base, exp, mod"),
+ GVAR_FUNC(IS_PROBAB_PRIME_INT, 2, "n, reps"),
+ GVAR_FUNC(INVMODINT, 2, "base, mod"),
+ GVAR_FUNC(HexStringInt, 1, "gmp"),
+ GVAR_FUNC(IntHexString, 1, "string"),
+ GVAR_FUNC(Log2Int, 1, "gmp"),
+ GVAR_FUNC(STRING_INT, 1, "gmp"),
+ GVAR_FUNC(INT_STRING, 1, "string"),
+ GVAR_FUNC(RandomIntegerMT, 2, "mtstr, nrbits"),
+ { 0, 0, 0, 0, 0 }
 
 };