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| Current File : //usr/share/gap/lib/float.gi |
#############################################################################
##
#W float.gi GAP library Steve Linton
## Laurent Bartholdi
##
##
#Y Copyright (C) 2011 The GAP Group
##
## This file deals with floats, and sets up a default interface, within GAP,
## to deal with floateans.
##
#############################################################################
## a category describing the "fields" of floating-point numbers
## we must put it here, because float.gd is read too early for "IsAlgebra"
## this is used mainly to create polynomials
DeclareCategory("IsFloatPseudoField", IsAlgebra);
## these things should also be in float.gd, but require IsRationalFunction
DeclareCategory("IsFloatRationalFunction", IsRationalFunction);
DeclareSynonym("IsFloatPolynomial", IsFloatRationalFunction and IsPolynomial);
DeclareSynonym("IsFloatUnivariatePolynomial", IsFloatRationalFunction and IsUnivariatePolynomial);
DeclareOperation("Value", [IsFloatRationalFunction,IsFloat]);
DeclareOperation("ValueInterval", [IsFloatRationalFunction,IsFloat]);
#############################################################################
MAX_FLOAT_LITERAL_CACHE_SIZE := 0; # cache all float literals by default.
FLOAT_DEFAULT_REP := fail;
FLOAT_STRING := fail;
FLOAT_PSEUDOFIELD := fail;
FLOAT := fail; # holds the constants
if IsHPCGAP then
BindGlobal("EAGER_FLOAT_LITERAL_CONVERTERS", AtomicRecord());
else
BindGlobal("EAGER_FLOAT_LITERAL_CONVERTERS", rec());
fi;
InstallGlobalFunction(SetFloats, function(arg)
local i, r, prec, install;
r := fail;
prec := fail;
install := true;
for i in [1..Length(arg)] do
if IsRecord(arg[i]) and i=1 then
r := arg[1];
elif IsBool(arg[i]) then
install := arg[i];
elif IsPosInt(arg[i]) then
prec := arg[i];
else
r := fail;
break;
fi;
od;
while r=fail do
Error("SetFloats requires a record, and optional precision(posint) and install(bool), not ",arg);
od;
if install then
if IsBound(r.filter) then
FLOAT_DEFAULT_REP := r.filter;
fi;
if IsBound(r.constants) then
FLOAT := r.constants;
fi;
if IsBound(r.creator) then
FLOAT_STRING := r.creator;
fi;
if IsBound(r.field) then
FLOAT_PSEUDOFIELD := r.field;
fi;
fi;
if IsBound(r.creator) and IsBound(r.eager) then
EAGER_FLOAT_LITERAL_CONVERTERS.([r.eager]) := r.creator;
fi;
FLUSH_FLOAT_LITERAL_CACHE();
if prec<>fail then
r.constants.MANT_DIG := prec;
if IsBound(r.constants.recompute) then
r.constants.recompute(r.constants,prec);
fi;
fi;
end);
################################################################
# creators
################################################################
InstallGlobalFunction(Float, function(obj)
if not IsString(obj) and IsList(obj) then
return List(obj,Float);
else
return NewFloat(FLOAT_DEFAULT_REP,obj);
fi;
end);
BindGlobal("INSTALLFLOATCONSTRUCTORS", function(arg)
local filter, float, constants, i;
if IsRecord(arg[1]) then
filter := arg[1].filter;
else
filter := arg[1];
fi;
InstallMethod(NewFloat, [filter,IsRat], -1, function(filter,obj)
return NewFloat(filter,NumeratorRat(obj))/NewFloat(filter,DenominatorRat(obj));
end);
InstallMethod(NewFloat, [filter,IsInfinity], -1, function(filter,obj)
return Inverse(NewFloat(filter,0));
end);
InstallMethod(NewFloat, [filter,IsNegInfinity], -1, function(filter,obj)
return -Inverse(NewFloat(filter,0));
end);
InstallMethod(NewFloat, [filter,IsList], -1, function(filter,mantexp)
if mantexp[1]=0 then
if mantexp[2]=0 then return NewFloat(filter,0);
elif mantexp[2]=1 then return Inverse(-Inverse(NewFloat(filter,0)));
elif mantexp[2]=2 then return Inverse(NewFloat(filter,0));
elif mantexp[2]=3 then return -Inverse(NewFloat(filter,0));
else return NewFloat(filter,0)/NewFloat(filter,0);
fi;
fi;
return NewFloat(filter,mantexp[1])*2^(mantexp[2]-LogInt(AbsoluteValue(mantexp[1]),2)-1);
end);
InstallMethod(NewFloat, [filter,filter], -1, function(filter,obj)
return obj; # floats are immutable, no harm to return the same one
end);
InstallMethod(MakeFloat, [filter,IsRat], -1, function(filter,obj)
return MakeFloat(filter,NumeratorRat(obj))/MakeFloat(filter,DenominatorRat(obj));
end);
InstallMethod(MakeFloat, [filter,IsInfinity], -1, function(filter,obj)
return Inverse(MakeFloat(filter,0));
end);
InstallMethod(MakeFloat, [filter,IsNegInfinity], -1, function(filter,obj)
return -Inverse(MakeFloat(filter,0));
end);
InstallMethod(MakeFloat, [filter,IsList], -1, function(filter,mantexp)
if mantexp[1]=0 then
if mantexp[2]=0 then return MakeFloat(filter,0);
elif mantexp[2]=1 then return Inverse(-Inverse(MakeFloat(filter,0)));
elif mantexp[2]=2 then return Inverse(MakeFloat(filter,0));
elif mantexp[2]=3 then return -Inverse(MakeFloat(filter,0));
else return MakeFloat(filter,0)/MakeFloat(filter,0);
fi;
fi;
return MakeFloat(filter,mantexp[1])*2^(mantexp[2]-LogInt(AbsoluteValue(mantexp[1]),2)-1);
end);
InstallMethod(MakeFloat, [filter,filter], -1, function(filter,obj)
return obj; # floats are immutable, no harm to return the same one
end);
if IsRecord(arg[1]) and IsBound(arg[1].constants) then
float := arg[1].constants;
constants := [["E","2.7182818284590452354"],
["LOG2E", "1.4426950408889634074"],
["LOG10E", "0.43429448190325182765"],
["LN2", "0.69314718055994530942"],
["LN10", "2.30258509299404568402"],
["PI", "3.14159265358979323846"],
["2PI", "6.28318530717958647692"],
["PI_2", "1.57079632679489661923"],
["PI_4", "0.78539816339744830962"],
["1_PI", "0.31830988618379067154"],
["2_PI", "0.63661977236758134308"],
["2_SQRTPI", "1.12837916709551257390"],
["SQRT2", "1.41421356237309504880"],
["SQRT1_2", "0.70710678118654752440"]];
for i in constants do
if not IsBound(float.(i[1])) then
float.(i[1]) := NewFloat(filter,i[2]);
fi;
od;
fi;
end);
################################################################
# inner converter from string to float
################################################################
BindGlobal("CONVERT_FLOAT_LITERAL", function(s)
local i,l,f,s1,s2;
f:= FLOAT_STRING(s);
if f<>fail then return f; fi;
l := LENGTH(s);
s1 := "";
for i in [1..LENGTH(s)] do
if s[i] in ".0123456789eE+-" then
s1[i] := s[i];
elif s[i] in "dDqQ" then
s1[i] := 'e';
else
s1 := fail; break;
fi;
od;
if s1<>fail then
f := FLOAT_STRING(s1);
if f<>fail then return f; fi;
fi;
return fail; # conversion failure; signal the kernel that something went wrong
end);
BindGlobal("CONVERT_FLOAT_LITERAL_EAGER", function(s,mark)
local f;
if mark = '\000' then
return CONVERT_FLOAT_LITERAL(s);
else
if not IsBound(EAGER_FLOAT_LITERAL_CONVERTERS.([mark])) then
Error("Unknown float literal conversion ",mark);
else
f := EAGER_FLOAT_LITERAL_CONVERTERS.([mark]);
if not IsFunction(f) then
Error("Float literal conversion for ",mark," bound to non-function");
fi;
return f(s);
fi;
fi;
end);
################################################################
# zeros
################################################################
InstallGlobalFunction(RootsFloat, function(arg)
local l;
if Length(arg)=1 and IsList(arg[1]) then
l := arg[1];
elif ForAll(arg,IsFloat) then
l := arg;
elif Length(arg)=1 and IsUnivariatePolynomial(arg[1]) then
l := CoefficientsOfUnivariatePolynomial(arg[1]);
else
Error("RootsFloat: expected coefficients, a list of coefficients, or a polynomial, not ",arg);
fi;
if Length(l)=0 then return []; fi;
return RootsFloatOp(l,l[1]);
end);
#############################################################################
## Default methods
##
## These methods have priority -1, because they are inefficient.
## Hopefully every float implementation implements them better.
#############################################################################
InstallMethod( Diameter, "for a float interval", [ IsFloatInterval ],
AbsoluteDiameter );
InstallMethod( AbsoluteValue, "for real floats", [ IsRealFloat ], -1,
function ( x )
if x < Zero(x) then return -x; else return x; fi;
end );
InstallMethod( Norm, "for real floats", [ IsRealFloat ], -1,
function ( x )
return x*x;
end );
InstallMethod( SignFloat, "for real floats", [ IsRealFloat ], -1,
function ( x )
if IsZero( x ) then
return 0;
elif x < Zero( x ) then
return -1;
else
return 1;
fi;
end );
InstallMethod( Exp2, "for floats", [ IsFloat ], -1,
function ( x )
return Exp(Log(MakeFloat(x,2))*x);
end );
InstallMethod( Exp10, "for floats", [ IsFloat ], -1,
function ( x )
return Exp(Log(MakeFloat(x,10))*x);
end );
InstallMethod( Expm1, "for floats", [ IsFloat ], -1,
function ( x )
return Exp(x)-MakeFloat(x,1);
end );
InstallMethod( Log2, "for floats", [ IsFloat ], -1,
function ( x )
return Log(x) / Log(MakeFloat(x,2));
end );
InstallMethod( Log10, "for floats", [ IsFloat ], -1,
function ( x )
return Log(x) / Log(MakeFloat(x,10));
end );
InstallMethod( Log1p, "for floats", [ IsFloat ], -1,
function ( x )
return Log(MakeFloat(x,1)+x);
end );
InstallMethod( Sec, "for floats", [ IsFloat ], -1,
function ( x )
return Inverse(Cos(x));
end );
InstallMethod( Csc, "for floats", [ IsFloat ], -1,
function ( x )
return Inverse(Sin(x));
end );
InstallMethod( Cot, "for floats", [ IsFloat ], -1,
function ( x )
return Inverse(Tan(x));
end );
InstallMethod( Sech, "for floats", [ IsFloat ], -1,
function ( x )
return Inverse(Cosh(x));
end );
InstallMethod( Csch, "for floats", [ IsFloat ], -1,
function ( x )
return Inverse(Sinh(x));
end );
InstallMethod( Coth, "for floats", [ IsFloat ], -1,
function ( x )
return Inverse(Tanh(x));
end );
InstallMethod( CubeRoot, "for floats", [ IsFloat ], -1,
function ( x )
if x>Zero(x) then
return Exp(Log(x)/3);
elif IsZero(x) then
return x;
else
return -Exp(Log(-x)/3);
fi;
end );
InstallMethod( Square, "for floats", [ IsFloat ], -1,
function ( x )
return x*x;
end );
InstallMethod( Hypothenuse, "for floats", [ IsFloat, IsFloat ], -1,
function ( x, y )
return Sqrt(x*x+y*y);
end );
InstallMethod( Ceil, "for real floats", [ IsRealFloat ], -1,
function ( x )
return -Floor(-x);
end );
# this is disabled because it's so bad... it loses an ulp in fringe cases.
#InstallMethod( Round, "for floats", [ IsFloat ], -1,
# function ( x )
# return Floor(x+MakeFloat(x,1/2));
#end );
InstallMethod( Trunc, "for real floats", [ IsRealFloat ], -1,
function ( x )
if x>Zero(x) then
return Floor(x);
else
return -Floor(-x);
fi;
end );
InstallMethod( Frac, "for floats", [ IsFloat ], -1,
function ( x )
return x-Floor(x);
end );
InstallMethod( SinCos, "for floats", [ IsFloat ], -1,
function ( x )
return [Sin(x), Cos(x)];
end );
InstallMethod( Hypothenuse, "for floats", [ IsFloat, IsFloat ], -1,
function ( x, y )
return Sqrt(x*x+y*y);
end );
InstallMethod( FrExp, "for floats", [ IsFloat ], -1,
function(obj)
local m, e, s;
if IsZero(obj) then return [0,0]; fi;
if obj>Zero(obj) then s := 1; else s := -1; obj := -obj; fi;
e := Int(Log2(obj))+1;
m := obj/2^e;
return [m,e];
end);
InstallMethod( LdExp, "for floats", [ IsFloat, IsInt ], -1,
function(m,e)
return m*2^e;
end);
InstallMethod( ExtRepOfObj, "for floats", [ IsFloat ], -1,
function(obj)
local p, v, sgn;
if IsZero(obj) then # special treatment for 0 and -0
if 1/obj > Zero(obj) then
return [0,0];
else
return [0,1];
fi;
elif IsPInfinity(obj) then
return [0,2];
elif IsNInfinity(obj) then
return [0,3];
elif IsNaN(obj) then
return [0,4];
fi;
p := FrExp(obj);
v := p[1];
while v mod One(v) <> Zero(v) do v := 2*v; od;
return [Int(v),p[2]];
end);
InstallMethod( ObjByExtRep, "for floats", [ IsFloatFamily, IsCyclotomicCollection ], -1,
function(fam,obj)
if obj[1]=0 then
if obj[2]=0 then
return 0.0; # 0
elif obj[2]=1 then
return 1/(-(1.0/0.0)); # -0
elif obj[2]=2 then
return 1.0/0.0; # inf
elif obj[2]=3 then
return -1.0/0.0; # -inf
elif obj[2]=4 then
return 0.0/0.0; # NaN
elif obj[2]=5 then
return -0.0/0.0; # -NaN
else
Error("Unknown external float representation ",obj);
fi;
fi;
return LdExp(Float(obj[1]),obj[2]-LogInt(AbsInt(obj[1]),2)-1);
end);
InstallMethod( ViewObj, "for floats", [ IsFloat ],
function ( x )
Print(ViewString(x));
end);
InstallMethod( Display, "for floats", [ IsFloat ],
function ( x )
Print(DisplayString(x));
end);
InstallMethod( PrintObj, "for floats", [ IsFloat ],
function ( x )
Print(String(x));
end);
InstallMethod( DisplayString, "for floats", [ IsFloat ], f->Concatenation(String(f),"\n"));
InstallMethod( ViewString, "for floats", [ IsFloat ], String );
InstallMethod( IsPInfinity, "for floats", [ IsFloat ], -1,
x->x=x+x and x>-x);
InstallMethod( IsNInfinity, "for floats", [ IsFloat ], -1,
x->x=x+x and x<-x);
InstallMethod( IsXInfinity, "for floats", [ IsFloat ], -1,
x->x=x+x and x<>-x);
InstallMethod( IsFinite, "for floats", [ IsFloat ], -1,
x->not IsXInfinity(x) and not IsNaN(x));
InstallMethod( IsNaN, "for floats", [ IsFloat ], -1, # IEEE754, not GAP standard
x->x<>x+Zero(x));
InstallMethod( EqFloat, "for floats", [ IsFloat, IsFloat ], -1,
function(x,y)
return (not IsNaN(x)) and x=y;
end);
InstallMethod( Zero, "for floats", [ IsFloat ], -1,
function(x)
return MakeFloat(x,0);
end);
InstallMethod( One, "for floats", [ IsFloat ], -1,
function(x)
return MakeFloat(x,1);
end);
#############################################################################
##
#M Rat( x ) . . . . . . . . . . . . . . . . . . . . . . . . . . . for macfloats
##
InstallOtherMethod( Rat, "for floats", [ IsFloat ],
function ( x )
local M, a_i, i, sign, maxdenom, maxpartial;
i := 0; M := [[1,0],[0,1]];
maxdenom := ValueOption("maxdenom");
maxpartial := ValueOption("maxpartial");
if maxpartial=fail then maxpartial := 10000; fi;
if maxdenom=fail then maxdenom := 10^QuoInt(FLOAT.DECIMAL_DIG,2); fi;
if x < Zero(x) then sign := -1; x := -x; else sign := 1; fi;
repeat
a_i := Int(x);
if i >= 1 and a_i > maxpartial then break; fi;
M := M * [[a_i,1],[1,0]];
if x = Float(a_i) then break; fi;
x := One(x) / (x - a_i);
i := i+1;
until M[2][1] > maxdenom;
return sign * M[1][1]/M[2][1];
end );
InstallOtherMethod( Rat, "for float intervals", [ IsFloatInterval ],
function ( x )
local M, a;
if x < Zero(x) then
M := [[-1,0],[0,1]]; x := -x;
else
M := [[1,0],[0,1]];
fi;
repeat
a := Int(Sup(x));
M := M * [[a,1],[1,0]];
x := x-a;
if Zero(x) in x then break; fi;
x := Inverse(x);
until AbsoluteDiameter(x) >= One(x);
return M[1][1]/M[2][1];
end);
BindGlobal("CYC_FLOAT_DEGREE", function(x,n,prec)
local i, m, b, phi;
phi := Phi(n);
m := IdentityMat(phi+1);
b := [];
for i in [1..phi] do
Add(m[i],Int(LdExp(Cos(FLOAT.2PI*(i-1)/n),prec)));
Add(m[i],Int(LdExp(Sin(FLOAT.2PI*(i-1)/n),prec)));
b[i] := E(n)^(i-1);
od;
Add(m[phi+1],Int(LdExp(RealPart(x),prec)));
Add(m[phi+1],Int(LdExp(ImaginaryPart(x),prec)));
m := First(LLLReducedBasis(m).basis,r->r[phi+1]<>0);
return -b*m{[1..phi]}/m[phi+1];
end);
BindGlobal("CYC_FLOAT", function(x,prec)
local n, len, e, minlen, minn, mine;
n := 2;
minlen := infinity;
repeat
e := CYC_FLOAT_DEGREE(x,n,prec);
len := n*Norm(DenominatorCyc(e)*e)^2;
if len < minlen then
Info(InfoWarning,2,"Degree ",n,": ",e);
minlen := len;
minn := n;
mine := e;
fi;
n := n+1;
until n > 2*minn+4;
return mine;
end);
InstallMethod( Cyc, "for floats, degree", [ IsFloat, IsPosInt ], -1,
function(x,n)
local prec;
prec := ValueOption("bits");
if not IsPosInt(prec) then prec := PrecisionFloat(x); fi;
return CYC_FLOAT_DEGREE(x,n,prec);
end);
InstallMethod( Cyc, "for intervals, degree", [ IsFloatInterval, IsPosInt ], -1,
function(x,n)
local diam;
diam := AbsoluteDiameter(x);
if IsZero(diam) then
return CYC_FLOAT_DEGREE(Mid(x),n,PrecisionFloat(x));
else
return CYC_FLOAT_DEGREE(Mid(x),n,1+LogInt(1+Int(Inverse(diam)),2));
fi;
end);
InstallMethod( Cyc, "for floats", [ IsFloat ], -1,
function(x)
local n, len, e, minlen, minn, mine, prec;
prec := ValueOption("bits");
if not IsPosInt(prec) then prec := PrecisionFloat(x); fi;
return CYC_FLOAT(x,prec);
end);
InstallMethod( Cyc, "for intervals", [ IsFloatInterval ], -1,
function(x)
local diam;
diam := AbsoluteDiameter(x);
if IsZero(diam) then
return CYC_FLOAT(Mid(x),PrecisionFloat(x));
else
return CYC_FLOAT(Mid(x),1+LogInt(1+Int(Inverse(diam)),2));
fi;
end);
BindGlobal("FLOAT_MINIMALPOLYNOMIAL", function(x,n,ind,prec)
local z, i, m;
m := IdentityMat(n);
z := LdExp(One(x),prec);
for i in [1..n] do
Add(m[i],Int(RealPart(z)));
Add(m[i],Int(ImaginaryPart(z)));
z := z*x;
od;
m := LLLReducedBasis(m).basis[1];
return UnivariatePolynomialByCoefficients(CyclotomicsFamily,m{[n,n-1..1]},ind);
end);
InstallMethod( MinimalPolynomial, "for floats", [ IsRationals, IsFloat, IsPosInt ],
function(ring,x,ind)
local n, len, p, lastlen, lastp, prec;
prec := ValueOption("bits");
if not IsPosInt(prec) then
prec := PrecisionFloat(x);
if IsFloatInterval(x) then
p := AbsoluteDiameter(x);
if not IsZero(x) then
prec := 1+LogInt(1+Int(Inverse(p)),2);
fi;
fi;
fi;
if IsFloatInterval(x) then
x := Mid(x);
fi;
n := ValueOption("degree");
if IsPosInt(n) then
return FLOAT_MINIMALPOLYNOMIAL(x,n+1,ind,prec);
fi;
n := 1;
len := infinity;
p := fail;
repeat
lastlen := len;
lastp := p;
p := FLOAT_MINIMALPOLYNOMIAL(x,n+1,ind,prec);
len := (CoefficientsOfUnivariatePolynomial(p)^2)^n;
n := n+1;
until len > lastlen;
return lastp;
end);
################################################################
# rational functions
################################################################
# we need a new method, so that we keep track of the 0 and 1 of the
# specific pseudofield
InstallOtherMethod(RationalFunctionsFamily, "floats pseudofield",
[IsFloatPseudoField],
function(pf)
local fam;
# create a new family in the category <IsRationalFunctionsFamily>
fam := NewFamily("RationalFunctionsFamily(...)",
IsPolynomialFunction and IsPolynomialFunctionsFamilyElement
and IsFloatRationalFunction and IsRationalFunctionsFamilyElement,
CanEasilySortElements,
IsPolynomialFunctionsFamily and CanEasilySortElements and
IsRationalFunctionsFamily);
# default type for polynomials
fam!.defaultPolynomialType := NewType( fam,
IsPolynomial and IsPolynomialDefaultRep and
HasExtRepPolynomialRatFun);
# default type for univariate laurent polynomials
fam!.threeLaurentPolynomialTypes :=
[ NewType( fam,
IsLaurentPolynomial
and IsLaurentPolynomialDefaultRep and
HasIndeterminateNumberOfLaurentPolynomial and
HasCoefficientsOfLaurentPolynomial),
NewType( fam,
IsLaurentPolynomial
and IsLaurentPolynomialDefaultRep and
HasIndeterminateNumberOfLaurentPolynomial and
HasCoefficientsOfLaurentPolynomial and
IsConstantRationalFunction and IsUnivariatePolynomial),
NewType( fam,
IsLaurentPolynomial and IsLaurentPolynomialDefaultRep and
HasIndeterminateNumberOfLaurentPolynomial and
HasCoefficientsOfLaurentPolynomial and
IsUnivariatePolynomial)];
# default type for univariate rational functions
fam!.univariateRatfunType := NewType( fam,
IsUnivariateRationalFunctionDefaultRep and
HasIndeterminateNumberOfLaurentPolynomial and
HasCoefficientsOfUnivariateRationalFunction);
fam!.defaultRatFunType := NewType( fam,
IsRationalFunctionDefaultRep and
HasExtRepNumeratorRatFun and HasExtRepDenominatorRatFun);
# functions to add zipped lists
fam!.zippedSum := [ MONOM_GRLEX, \+ ];
# functions to multiply zipped lists
fam!.zippedProduct := [ MONOM_PROD,
MONOM_GRLEX, \+, \* ];
# set the one and zero coefficient
fam!.zeroCoefficient := Zero(pf);
fam!.oneCoefficient := One(pf);
fam!.oneCoefflist := Immutable([fam!.oneCoefficient]);
# set the coefficients
SetCoefficientsFamily( fam, FamilyObj(fam!.zeroCoefficient) );
SetCharacteristic( fam, 0 );
# and set one and zero
SetZero( fam, PolynomialByExtRepNC(fam,[]));
SetOne( fam, PolynomialByExtRepNC(fam,[[],fam!.oneCoefficient]));
# we will store separate `one's for univariate polynomials. This will
# allow to keep univariate calculations in this one indeterminate.
fam!.univariateOnePolynomials:=[];
fam!.univariateZeroPolynomials:=[];
# assign a names list
fam!.namesIndets := [];
# and return
return fam;
end);
InstallOtherMethod( UnivariatePolynomialByCoefficients, "ring",
[IsFloatPseudoField,IsList,IsInt],
function(r,cofs,ind)
return LaurentPolynomialByCoefficients(r,cofs,0,ind);
end );
InstallOtherMethod( LaurentPolynomialByCoefficients, "ring",
[IsFloatPseudoField,IsList,IsInt,IsInt],
function(r,cofs,val,ind)
local lc, fam;
lc := Length(cofs);
fam := RationalFunctionsFamily(r);
if lc > 0 and (IsZero( cofs[1] ) or IsZero( cofs[lc] )) then
cofs := ShallowCopy( cofs );
val := val + RemoveOuterCoeffs( cofs, fam!.zeroCoefficient );
fi;
return LaurentPolynomialByExtRepNC( fam, cofs, val, ind );
end );
InstallOtherMethod( UnivariateRationalFunctionByCoefficients, "ring",
[IsFloatPseudoField,IsList,IsList,IsInt],
function(r,ncof,dcof,val)
return UnivariateRationalFunctionByCoefficients(r,ncof,dcof,val,1);
end );
InstallOtherMethod( UnivariateRationalFunctionByCoefficients, "ring",
[IsFloatPseudoField,IsList,IsList,IsInt,IsInt],
function(r,ncof,dcof,val,ind)
local fam;
fam := RationalFunctionsFamily( r );
if Length( ncof ) > 0 and (IsZero( ncof[1] ) or IsZero( ncof[Length( ncof )] )) then
if not IsMutable( ncof ) then
ncof := ShallowCopy( ncof );
fi;
val := val + RemoveOuterCoeffs( ncof, fam!.zeroCoefficient );
fi;
if Length( dcof ) > 0 and (IsZero( dcof[1] ) or IsZero( dcof[Length( dcof )] )) then
if not IsMutable( dcof ) then
dcof := ShallowCopy( dcof );
fi;
val := val - RemoveOuterCoeffs( dcof, fam!.zeroCoefficient );
fi;
return UnivariateRationalFunctionByExtRepNC( fam, ncof, dcof, val, ind );
end );
InstallMethod( PolynomialRing,"indetlist", true, [ IsFloatPseudoField, IsList ],
1,
function( r, n )
local rfun, zero, one, ind, i, type, prng;
if IsPolynomialFunctionCollection(n) and ForAll(n,IsLaurentPolynomial) then
n:=List(n,IndeterminateNumberOfLaurentPolynomial);
fi;
if IsEmpty(n) or not IsInt(n[1]) then
TryNextMethod();
fi;
# get the rational functions of the elements family
rfun := RationalFunctionsFamily(r);
# cache univariate rings - they might be created often
if not IsBound(r!.univariateRings) then
r!.univariateRings:=[];
fi;
if Length(n)=1
# some bozo might put in a ridiculous number
and n[1]<10000
# only cache for the prime field
and IsField(r)
and IsBound(r!.univariateRings[n[1]]) then
return r!.univariateRings[n[1]];
fi;
# first the indeterminates
zero := Zero(r);
one := One(r);
ind := [];
for i in n do
Add( ind, LaurentPolynomialByCoefficients(r,[one],1,i) );
od;
# construct a polynomial ring
type := IsPolynomialRing and IsAttributeStoringRep and IsFreeLeftModule and IsAlgebraWithOne;
if Length(n) = 1 then
type := type and IsUnivariatePolynomialRing and IsEuclideanRing;
#and IsAlgebraWithOne; # done above already
fi;
prng := Objectify( NewType( CollectionsFamily(rfun), type ), rec() );
# set the left acting domain
SetLeftActingDomain( prng, r );
# set the indeterminates
SetIndeterminatesOfPolynomialRing( prng, ind );
# set known properties
SetIsFinite( prng, false );
SetIsFiniteDimensional( prng, false );
SetSize( prng, infinity );
# set the coefficients ring
SetCoefficientsRing( prng, r );
# set one and zero
SetOne( prng, ind[1]^0 );
SetZero( prng, ind[1]*zero );
# set the generators left operator ring-with-one if the rank is one
if IsRingWithOne(r) then
SetGeneratorsOfLeftOperatorRingWithOne( prng, ind );
fi;
if Length(n)=1 and n[1]<10000
# only cache for the prime field
and IsField(r) then
r!.univariateRings[n[1]]:=prng;
fi;
# and return
return prng;
end );
InstallOtherMethod( Indeterminate, [IsFloatFamily,IsPosInt],
function(fam,ind)
Error("`Indeterminate(<family>,<ind>)' can not be used with floats; use `Indeterminate(<float pseudofield>,<ind>)'");
end);
InstallOtherMethod( Indeterminate,"number", true, [ IsFloatPseudoField,IsPosInt ],0,
function( r,n )
return LaurentPolynomialByCoefficients(r,[One(r)],1,n);
end);
InstallOtherMethod( Indeterminate,"number 1", true, [ IsFloatPseudoField ],0,
function( r )
return LaurentPolynomialByCoefficients(r,[One(r)],1,1);
end);
InstallOtherMethod( Indeterminate,"number, avoid", true, [ IsFloatPseudoField,IsList ],0,
function( r,a )
if not IsRationalFunction(a[1]) then
TryNextMethod();
fi;
return LaurentPolynomialByCoefficients(r,[One(r)],1,
GiveNumbersNIndeterminates(RationalFunctionsFamily(r),1,[],a)[1]);
end);
InstallOtherMethod( Indeterminate,"number, name", true, [ IsFloatPseudoField,IsString ],0,
function( r,n )
if not IsString(n) then
TryNextMethod();
fi;
return LaurentPolynomialByCoefficients(r,[One(r)],1,
GiveNumbersNIndeterminates(RationalFunctionsFamily(r),1,[n],[])[1]);
end);
InstallOtherMethod( Indeterminate,"number, name, avoid",true,
[ IsFloatPseudoField,IsString,IsList ],0,
function( r,n,a )
if not IsString(n) then
TryNextMethod();
fi;
return LaurentPolynomialByCoefficients(r,[One(r)],1,
GiveNumbersNIndeterminates(RationalFunctionsFamily(r),1,[n],a)[1]);
end);
# we must avoid over/underflow here; hence the specific method
InstallOtherMethod(ReduceCoeffs, "for float vectors",
[IsFloatCollection, IsInt, IsFloatCollection, IsInt],
function (l1, n1, l2, n2)
local l, q, i, x;
if 0 = n2 then
Error("<l2> must be non-zero");
elif 0 = n1 then
return n1;
fi;
while 0 < n2 and IsZero(l2[n2]) do n2 := n2 - 1; od;
if 0 = n2 then
Error("<l2> must be non-zero");
fi;
while 0 < n1 and IsZero(l1[n1]) do n1 := n1 - 1; od;
while n1 >= n2 do
q := l1[n1] / l2[n2];
l := n1-n2;
for i in [ n1-n2+1 .. n1 ] do
x := l1[i] - q * l2[i-n1+n2];
if i=n1 or l1[i] - x/2 = l1[i] then # epsilon-small value
l1[i] := Zero(l1[i]);
else
l1[i] := x;
l := i;
fi;
od;
n1 := l;
od;
return n1;
end);
InstallMethod( Derivative, "for float laurent polynomial",
[IsFloatRationalFunction and IsUnivariateRationalFunction and IsLaurentPolynomial],
function(f)
local c, d, e, i, ind, fam;
ind := IndeterminateNumberOfUnivariateRationalFunction( f );
fam := FamilyObj(f);
e := CoefficientsOfLaurentPolynomial( f );
c := e[1];
if Length( c ) = 0 then
return f;
fi;
e := e[2];
d := [ ];
for i in [ 1 .. Length(c) ] do
d[i] := (i + e - 1) * c[i];
od;
e := e-1 + RemoveOuterCoeffs(d, fam!.zeroCoefficient);
return LaurentPolynomialByExtRepNC( fam, d, e, ind );
end );
#############################################################################
##
#M \<, \+, ... for float and rat
##
# we say that all floateans are after all rationals, to sort them
BindGlobal("COMPARE_FLOAT_ANY", function(x,y)
local z;
if IsFloat(x) then z := y; else z := x; fi;
Error("Comparison of float and ",z," is not supported. Please refer to the manual section on floats for details");
end);
InstallMethod( \<, "for rational and float", [ IsRat, IsFloat ], -1, COMPARE_FLOAT_ANY );
InstallMethod( \<, "for float and rational", [ IsFloat, IsRat ], -1, COMPARE_FLOAT_ANY );
InstallMethod( \<, "for floats", [ IsFloat, IsFloat ], -1,
function(x,y) return x < MakeFloat(x,y); end);
InstallMethod( \=, "for rational and float", [ IsRat, IsFloat ], -1, COMPARE_FLOAT_ANY );
InstallMethod( \=, "for float and rational", [ IsFloat, IsRat ], -1, COMPARE_FLOAT_ANY );
InstallMethod( \=, "for floats", [ IsFloat, IsFloat ], -1,
function(x,y) return x = MakeFloat(x,y); end);
InstallMethod( \+, "for rational and float", ReturnTrue, [ IsRat, IsFloat ], -1,
function ( x, y ) return MakeFloat(y,x) + y; end );
InstallMethod( \+, "for float and rational", ReturnTrue, [ IsFloat, IsRat ], -1,
function ( x, y ) return x + MakeFloat(x,y); end );
InstallMethod( \+, "for floats", ReturnTrue, [ IsFloat, IsFloat ], -1,
function ( x, y ) return x + MakeFloat(x,y); end );
InstallMethod( \-, "for rational and float", ReturnTrue, [ IsRat, IsFloat ], -1,
function ( x, y ) return MakeFloat(y,x) - y; end );
InstallMethod( \-, "for float and rational", ReturnTrue, [ IsFloat, IsRat ], -1,
function ( x, y ) return x - MakeFloat(x,y); end );
InstallMethod( \-, "for floats", ReturnTrue, [ IsFloat, IsFloat ], -1,
function ( x, y ) return x - MakeFloat(x,y); end );
InstallMethod( \*, "for rational and float", ReturnTrue, [ IsRat, IsFloat ], -1,
function ( x, y ) return MakeFloat(y,x) * y; end );
InstallMethod( \*, "for float and rational", ReturnTrue, [ IsFloat, IsRat ], -1,
function ( x, y ) return x * MakeFloat(x,y); end );
InstallMethod( \*, "for floats", ReturnTrue, [ IsFloat, IsFloat ], -1,
function ( x, y ) return x * MakeFloat(x,y); end );
InstallMethod( \/, "for rational and float", ReturnTrue, [ IsRat, IsFloat ], -1,
function ( x, y ) return MakeFloat(y,x) / y; end );
InstallMethod( \/, "for float and rational", ReturnTrue, [ IsFloat, IsRat ], -1,
function ( x, y ) return x / MakeFloat(x,y); end );
InstallMethod( \/, "for floats", ReturnTrue, [ IsFloat, IsFloat ], -1,
function ( x, y ) return x / MakeFloat(x,y); end );
InstallMethod( LQUO, "for rational and float", ReturnTrue, [ IsRat, IsFloat ], -1,
function ( x, y ) return LQUO(MakeFloat(y,x),y); end );
InstallMethod( LQUO, "for float and rational", ReturnTrue, [ IsFloat, IsRat ], -1,
function ( x, y ) return LQUO(x,MakeFloat(x,y)); end );
InstallMethod( LQUO, "for floats", ReturnTrue, [ IsFloat, IsFloat ], -1,
function ( x, y ) return LQUO(x,MakeFloat(x,y)); end );
InstallOtherMethod( \/, "for empty list", [ IsEmpty, IsFloat ],
function ( x, y ) return x; end );
InstallMethod( \^, "for rational and float", ReturnTrue, [ IsRat, IsFloat ], -1,
function ( x, y ) return MakeFloat(y,x) ^ y; end );
InstallMethod( \^, "for float and rational", ReturnTrue, [ IsFloat, IsRat ], -1,
function ( x, y )
if IsInt(y) then TryNextMethod(); fi;
return x ^ MakeFloat(x,y);
end );
InstallMethod( \^, "for floats", ReturnTrue, [ IsFloat, IsFloat ], -1,
function ( x, y ) return x ^ MakeFloat(x,y); end );
InstallMethod( IsGeneratorsOfMagmaWithInverses,
"for a collection of floats (return false)",
[ IsFloatCollection ],
SUM_FLAGS, # override everything else
function( gens )
Info( InfoWarning, 1,
"no groups of floats allowed because of incompatible ^" );
return false;
end );
#############################################################################
##
#E