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Polynomial quotient and remainder.
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corywalker committed Jul 7, 2017
1 parent 82ccb1b commit 6c5aac0
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Showing 6 changed files with 61 additions and 7 deletions.
6 changes: 4 additions & 2 deletions expreduce/builtin_pattern.go
Expand Up @@ -91,8 +91,6 @@ func GetPatternDefinitions() (defs []Definition) {

// Test pinning in orderless
&SameTest{"{{b[[1]],b},{y,a},{y,c},{b[[1]],b},{x,a},{y,c},{b[[1]],b},{x,c},{y,a},{b[[1]],b},{x,a},{x,c}}", "pats"},

&SameTest{"True", "MatchQ[__, Optional[1]*a_]"},
},
KnownFailures: []TestInstruction{
// Test order of pattern checking
Expand Down Expand Up @@ -567,9 +565,13 @@ func GetPatternDefinitions() (defs []Definition) {

&SameTest{"True", "MatchQ[-x,p_.]"},
&SameTest{"True", "MatchQ[-x*a,p_.*a]"},

&SameTest{"True", "MatchQ[__, Optional[1]*a_]"},
&SameTest{"True", "MatchQ[x^x, x^Optional[exp_]]"},
},
KnownFailures: []TestInstruction{
&SameTest{"foo[a,b]", "foo[a,b]/.foo[a___,b_.,d_.]->{{a},{b},{d}}"},
&SameTest{"True", "MatchQ[x^x, (x^x)^Optional[exp_]]"},
},
})
return
Expand Down
31 changes: 30 additions & 1 deletion expreduce/builtin_power.go
Expand Up @@ -323,7 +323,6 @@ func GetPowerDefinitions() (defs []Definition) {
// the result so it does match up.
&SameTest{"{0,3,5,x^x}", "Exponent[3 + \"hello\" + x^3 + a*x^5 + x^x^x, x, List]//Sort"},
&SameTest{"{0}", "Exponent[1 + x^x^x, x^x, List]"},
&SameTest{"{0,1}", "Exponent[1 + x^x^x, x^x^x, List]"},
&SameTest{"{0}", "Exponent[2 + a, x, List]"},
&SameTest{"{0}", "Exponent[a, x, List]"},
&SameTest{"{2}", "Exponent[x^2, x, List]"},
Expand All @@ -339,6 +338,9 @@ func GetPowerDefinitions() (defs []Definition) {
&SameTest{"{0,1}", "Exponent[1 + b*x + x^2 - (x*(1 + a*x))/a, x, List]"},
&SameTest{"{0,1}", "Exponent[1 + x + x^2 - (x*(1 + 2*x))/2, x, List]"},
},
KnownFailures: []TestInstruction{
&SameTest{"{0,1}", "Exponent[1 + x^x^x, x^x^x, List]"},
},
})
defs = append(defs, Definition{
Name: "Coefficient",
Expand All @@ -359,5 +361,32 @@ func GetPowerDefinitions() (defs []Definition) {
&SameTest{"1/2", "Coefficient[1 + x + x^2 - (x*(1 + 2*x))/2, x]"},
},
})
defs = append(defs, Definition{
Name: "PolynomialQuotientRemainder",
Usage: "`PolynomialQuotientRemainder[poly_, div_, var_]` returns the quotient and remainder of `poly` divided by `div` treating `var` as the polynomial variable.",
SimpleExamples: []TestInstruction{
&SameTest{"{x^2/2,2}", "PolynomialQuotientRemainder[2 + x^2 + x^3, 2 + 2*x, x]"},
&SameTest{"{x^2-x y+y^2,-y^3}", "PolynomialQuotientRemainder[x^3, x + y, x]"},
&SameTest{"{x/a,1-x/a}", "PolynomialQuotientRemainder[1 + x^3, 1 + a*x^2, x]"},
},
})
defs = append(defs, Definition{
Name: "PolynomialQuotient",
Usage: "`PolynomialQuotient[poly_, div_, var_]` returns the quotient of `poly` divided by `div` treating `var` as the polynomial variable.",
SimpleExamples: []TestInstruction{
&SameTest{"x^2/2", "PolynomialQuotient[2 + x^2 + x^3, 2 + 2*x, x]"},
&SameTest{"x^2-x y+y^2", "PolynomialQuotient[x^3, x + y, x]"},
&SameTest{"x/a", "PolynomialQuotient[1 + x^3, 1 + a*x^2, x]"},
},
})
defs = append(defs, Definition{
Name: "PolynomialRemainder",
Usage: "`PolynomialRemainder[poly_, div_, var_]` returns the remainder of `poly` divided by `div` treating `var` as the polynomial variable.",
SimpleExamples: []TestInstruction{
&SameTest{"2", "PolynomialRemainder[2 + x^2 + x^3, 2 + 2*x, x]"},
&SameTest{"-y^3", "PolynomialRemainder[x^3, x + y, x]"},
&SameTest{"1-x/a", "PolynomialRemainder[1 + x^3, 1 + a*x^2, x]"},
},
})
return
}
2 changes: 2 additions & 0 deletions expreduce/builtin_system.go
Expand Up @@ -210,6 +210,7 @@ func GetSystemDefinitions() (defs []Definition) {
}
return ToStringInfixAdvanced(this.Parts[1:], " = ", true, "(", ")", form)
},
Bootstrap: true,
legacyEvalFn: func(this *Expression, es *EvalState) Ex {
if len(this.Parts) != 3 {
return this
Expand Down Expand Up @@ -342,6 +343,7 @@ func GetSystemDefinitions() (defs []Definition) {
defs = append(defs, Definition{
Name: "Print",
Usage: "`Print[expr1, expr2, ...]` prints the string representation of the expressions to the console and returns `Null`.",
Bootstrap: true,
legacyEvalFn: func(this *Expression, es *EvalState) Ex {
if len(this.Parts) < 2 {
return this
Expand Down
2 changes: 0 additions & 2 deletions expreduce/ex_expression.go
Expand Up @@ -4,8 +4,6 @@ import "bytes"
import "math/big"
import "sort"

//import "fmt"

type Expression struct {
Parts []Ex
//needsEval bool
Expand Down
1 change: 0 additions & 1 deletion expreduce/parse_form.go
Expand Up @@ -79,7 +79,6 @@ func ParseForm(lhs_component Ex, isFlat bool, sequenceHead string, headDefault E
if len(optional.Parts) >= 3 {
defaultToUse = optional.Parts[2]
}
cl.Debugf("%v", optional)
if len(optional.Parts) >= 2 {
startI = 0
if defaultToUse == nil {
Expand Down
26 changes: 25 additions & 1 deletion expreduce/resources/power.er
Expand Up @@ -9,7 +9,7 @@ genExpand[addends_List, exponents_List] :=
genVars[addends, exponents[[ExpandUnique`i]]], {ExpandUnique`i, 1,
Length[exponents]}];
Expand[a_] := a //. {
s_Plus^n_Integer :>
s_Plus^n_Integer?Positive :>
genExpand[List @@ s, possibleExponents[n, Length[s]]],
c_*s_Plus :> ((c*#) &) /@ s
};
Expand Down Expand Up @@ -50,3 +50,27 @@ Coefficient[inP_, inTerm_] :=
];

Attributes[Coefficient] = {Listable, Protected};

ExpreduceLeadingCoeff[p_, x_] := Coefficient[p, x^Exponent[p, x]];
PolynomialQuotientRemainder[inp_, inq_, v_] :=
Module[{a = inp, b = inq, x = v, r, d, c, i, s, q},
q = 0;
r = a;
d = Exponent[b, x];
c = ExpreduceLeadingCoeff[b, x];
i = 1;
While[Exponent[r, x] >= d && i < 20,
s = (ExpreduceLeadingCoeff[r, x]/c)*x^(Exponent[r, x] - d);
q = q + s;
r = r - s*b;
i = i + 1;
];
{q, r} // Expand
];
Attributes[PolynomialQuotientRemainder] = {Protected};
PolynomialQuotient[inp_, inq_, v_] :=
PolynomialQuotientRemainder[inp, inq, v][[1]];
Attributes[PolynomialQuotient] = {Protected};
PolynomialRemainder[inp_, inq_, v_] :=
PolynomialQuotientRemainder[inp, inq, v][[2]];
Attributes[PolynomialRemainder] = {Protected};

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