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Introduce kernel-level LCM_INT #2019

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Dec 17, 2017
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Introduce kernel-level LCM_INT #2019

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e81afc2
Introduce kernel-level LCM_INT
markuspf Nov 24, 2017
13118fe
Add some tests for LcmInt
markuspf Dec 13, 2017
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8 changes: 1 addition & 7 deletions hpcgap/lib/integer.gi
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Original file line number Diff line number Diff line change
Expand Up @@ -1105,13 +1105,7 @@ 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);


#############################################################################
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8 changes: 1 addition & 7 deletions lib/integer.gi
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Expand Up @@ -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);


#############################################################################
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86 changes: 63 additions & 23 deletions src/integer.c
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Expand Up @@ -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);
}

/****************************************************************************
**
Expand Down Expand Up @@ -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 }

};

Expand Down
45 changes: 45 additions & 0 deletions tst/testinstall/intarith.tst
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Expand Up @@ -444,6 +444,51 @@ gap> GcdInt(-2^60, -2^60);
gap> GcdInt(-2^28, -2^28);
268435456

#
# LcmInt
#
gap> List(dataNonZero, x -> LcmInt(bigNeg, x));
[ 10000000000000000000100000000000000000000, 100000000000000000000,
100000000000000000000, 100000000000000000000, 100000000000000000000,
100000000000000000000, 100000000000000000000,
10000000000000000000100000000000000000000 ]
gap> List(dataNonZero, x -> LcmInt(smlNeg, x));
[ 1000000000000000000010000, 100000000000000000000, 10000, 10000, 10000,
10000, 100000000000000000000, 1000000000000000000010000 ]
gap> List(dataNonZero, x -> LcmInt(smlPos, x));
[ 1000000000000000000010000, 100000000000000000000, 10000, 10000, 10000,
10000, 100000000000000000000, 1000000000000000000010000 ]
gap> List(dataNonZero, x -> LcmInt(bigPos, x));
[ 10000000000000000000100000000000000000000, 100000000000000000000,
100000000000000000000, 100000000000000000000, 100000000000000000000,
100000000000000000000, 100000000000000000000,
10000000000000000000100000000000000000000 ]

#
gap> g:=3^10*257;; a:=g*991;; b:=g*1601;;
gap> LcmInt(2^20*a, 2^30*b) = 2^30*3^10*257*991*1601;
true
gap> LcmInt(2^80*a, 2^40*b) = 2^80*3^10*257*991*1601;
true
gap> LcmInt(2^80*a, 2^90*b) = 2^90*3^10*257*991*1601;
true

# check symmetry
gap> ForAll(data, x -> ForAll(data, y -> LcmInt(x,y) = LcmInt(y,x)));
true

#
gap> LcmInt(fail,1);
Error, LcmInt: <left> must be an integer (not a boolean or fail)
gap> LcmInt(1,fail);
Error, LcmInt: <right> must be an integer (not a boolean or fail)

# corner cases
gap> LcmInt(-2^60, -2^60);
1152921504606846976
gap> LcmInt(-2^28, -2^28);
268435456

#
# AInvInt
#
Expand Down