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+\documentclass{article}
+\usepackage{axiom}
+\begin{document}
+\title{\$SPAD/src/algebra rdeef.spad}
+\author{Manuel Bronstein}
+\maketitle
+\begin{abstract}
+\end{abstract}
+\eject
+\tableofcontents
+\eject
+\section{package INTTOOLS IntegrationTools}
+<<package INTTOOLS IntegrationTools>>=
+)abbrev package INTTOOLS IntegrationTools
+++ Tools for the integrator
+++ Author: Manuel Bronstein
+++ Date Created: 25 April 1990
+++ Date Last Updated: 9 June 1993
+++ Keywords: elementary, function, integration.
+IntegrationTools(R:OrderedSet, F:FunctionSpace R): Exp == Impl where
+ K ==> Kernel F
+ SE ==> Symbol
+ P ==> SparseMultivariatePolynomial(R, K)
+ UP ==> SparseUnivariatePolynomial F
+ IR ==> IntegrationResult F
+ ANS ==> Record(special:F, integrand:F)
+ U ==> Union(ANS, "failed")
+ ALGOP ==> "%alg"
+
+ Exp ==> with
+ varselect: (List K, SE) -> List K
+ ++ varselect([k1,...,kn], x) returns the ki which involve x.
+ kmax : List K -> K
+ ++ kmax([k1,...,kn]) returns the top-level ki for integration.
+ ksec : (K, List K, SE) -> K
+ ++ ksec(k, [k1,...,kn], x) returns the second top-level ki
+ ++ after k involving x.
+ union : (List K, List K) -> List K
+ ++ union(l1, l2) returns set-theoretic union of l1 and l2.
+ vark : (List F, SE) -> List K
+ ++ vark([f1,...,fn],x) returns the set-theoretic union of
+ ++ \spad{(varselect(f1,x),...,varselect(fn,x))}.
+ if R has IntegralDomain then
+ removeConstantTerm: (F, SE) -> F
+ ++ removeConstantTerm(f, x) returns f minus any additive constant
+ ++ with respect to x.
+ if R has GcdDomain and F has ElementaryFunctionCategory then
+ mkPrim: (F, SE) -> F
+ ++ mkPrim(f, x) makes the logs in f which are linear in x
+ ++ primitive with respect to x.
+ if R has ConvertibleTo Pattern Integer and R has PatternMatchable Integer
+ and F has LiouvillianFunctionCategory and F has RetractableTo SE then
+ intPatternMatch: (F, SE, (F, SE) -> IR, (F, SE) -> U) -> IR
+ ++ intPatternMatch(f, x, int, pmint) tries to integrate \spad{f}
+ ++ first by using the integration function \spad{int}, and then
+ ++ by using the pattern match intetgration function \spad{pmint}
+ ++ on any remaining unintegrable part.
+
+ Impl ==> add
+ better?: (K, K) -> Boolean
+
+ union(l1, l2) == setUnion(l1, l2)
+ varselect(l, x) == [k for k in l | member?(x, variables(k::F))]
+ ksec(k, l, x) == kmax setUnion(remove(k, l), vark(argument k, x))
+
+ vark(l, x) ==
+ varselect(reduce("setUnion",[kernels f for f in l],empty()$List(K)), x)
+
+ kmax l ==
+ ans := first l
+ for k in rest l repeat
+ if better?(k, ans) then ans := k
+ ans
+
+-- true if x should be considered before y in the tower
+ better?(x, y) ==
+ height(y) ^= height(x) => height(y) < height(x)
+ has?(operator y, ALGOP) or
+ (is?(y, "exp"::SE) and not is?(x, "exp"::SE)
+ and not has?(operator x, ALGOP))
+
+ if R has IntegralDomain then
+ removeConstantTerm(f, x) ==
+ not freeOf?((den := denom f)::F, x) => f
+ (u := isPlus(num := numer f)) case "failed" =>
+ freeOf?(num::F, x) => 0
+ f
+ ans:P := 0
+ for term in u::List(P) repeat
+ if not freeOf?(term::F, x) then ans := ans + term
+ ans / den
+
+ if R has GcdDomain and F has ElementaryFunctionCategory then
+ psimp : (P, SE) -> Record(coef:Integer, logand:F)
+ cont : (P, List K) -> P
+ logsimp : (F, SE) -> F
+ linearLog?: (K, F, SE) -> Boolean
+
+ logsimp(f, x) ==
+ r1 := psimp(numer f, x)
+ r2 := psimp(denom f, x)
+ g := gcd(r1.coef, r2.coef)
+ g * log(r1.logand ** (r1.coef quo g) / r2.logand ** (r2.coef quo g))
+
+ cont(p, l) ==
+ empty? l => p
+ q := univariate(p, first l)
+ cont(unitNormal(leadingCoefficient q).unit * content q, rest l)
+
+ linearLog?(k, f, x) ==
+ is?(k, "log"::SE) and
+ ((u := retractIfCan(univariate(f,k))@Union(UP,"failed")) case UP)
+-- and one?(degree(u::UP))
+ and (degree(u::UP) = 1)
+ and not member?(x, variables leadingCoefficient(u::UP))
+
+ mkPrim(f, x) ==
+ lg := [k for k in kernels f | linearLog?(k, f, x)]
+ eval(f, lg, [logsimp(first argument k, x) for k in lg])
+
+ psimp(p, x) ==
+ (u := isExpt(p := ((p exquo cont(p, varselect(variables p, x)))::P)))
+ case "failed" => [1, p::F]
+ [u.exponent, u.var::F]
+
+ if R has Join(ConvertibleTo Pattern Integer, PatternMatchable Integer)
+ and F has Join(LiouvillianFunctionCategory, RetractableTo SE) then
+ intPatternMatch(f, x, int, pmint) ==
+ ir := int(f, x)
+ empty?(l := notelem ir) => ir
+ ans := ratpart ir
+ nl:List(Record(integrand:F, intvar:F)) := empty()
+ lg := logpart ir
+ for rec in l repeat
+ u := pmint(rec.integrand, retract(rec.intvar))
+ if u case ANS then
+ rc := u::ANS
+ ans := ans + rc.special
+ if rc.integrand ^= 0 then
+ ir0 := intPatternMatch(rc.integrand, x, int, pmint)
+ ans := ans + ratpart ir0
+ lg := concat(logpart ir0, lg)
+ nl := concat(notelem ir0, nl)
+ else nl := concat(rec, nl)
+ mkAnswer(ans, lg, nl)
+
+@
+\section{package RDEEF ElementaryRischDE}
+<<package RDEEF ElementaryRischDE>>=
+)abbrev package RDEEF ElementaryRischDE
+++ Risch differential equation, elementary case.
+++ Author: Manuel Bronstein
+++ Date Created: 1 February 1988
+++ Date Last Updated: 2 November 1995
+++ Keywords: elementary, function, integration.
+ElementaryRischDE(R, F): Exports == Implementation where
+ R : Join(GcdDomain, OrderedSet, CharacteristicZero,
+ RetractableTo Integer, LinearlyExplicitRingOver Integer)
+ F : Join(TranscendentalFunctionCategory, AlgebraicallyClosedField,
+ FunctionSpace R)
+
+ N ==> NonNegativeInteger
+ Z ==> Integer
+ SE ==> Symbol
+ LF ==> List F
+ K ==> Kernel F
+ LK ==> List K
+ P ==> SparseMultivariatePolynomial(R, K)
+ UP ==> SparseUnivariatePolynomial F
+ RF ==> Fraction UP
+ GP ==> LaurentPolynomial(F, UP)
+ Data ==> List Record(coeff:Z, argument:P)
+ RRF ==> Record(mainpart:F,limitedlogs:List NL)
+ NL ==> Record(coeff:F,logand:F)
+ U ==> Union(RRF, "failed")
+ UF ==> Union(F, "failed")
+ UUP ==> Union(UP, "failed")
+ UGP ==> Union(GP, "failed")
+ URF ==> Union(RF, "failed")
+ UEX ==> Union(Record(ratpart:F, coeff:F), "failed")
+ PSOL==> Record(ans:F, right:F, sol?:Boolean)
+ FAIL==> error("Function not supported by Risch d.e.")
+ ALGOP ==> "%alg"
+
+ Exports ==> with
+ rischDE: (Z, F, F, SE, (F, LF) -> U, (F, F) -> UEX) -> PSOL
+ ++ rischDE(n, f, g, x, lim, ext) returns \spad{[y, h, b]} such that
+ ++ \spad{dy/dx + n df/dx y = h} and \spad{b := h = g}.
+ ++ The equation \spad{dy/dx + n df/dx y = g} has no solution
+ ++ if \spad{h \~~= g} (y is a partial solution in that case).
+ ++ Notes: lim is a limited integration function, and
+ ++ ext is an extended integration function.
+
+ Implementation ==> add
+ import IntegrationTools(R, F)
+ import TranscendentalRischDE(F, UP)
+ import TranscendentalIntegration(F, UP)
+ import PureAlgebraicIntegration(R, F, F)
+ import FunctionSpacePrimitiveElement(R, F)
+ import ElementaryFunctionStructurePackage(R, F)
+ import PolynomialCategoryQuotientFunctions(IndexedExponents K,
+ K, R, P, F)
+
+ RF2GP: RF -> GP
+ makeData : (F, SE, K) -> Data
+ normal0 : (Z, F, F, SE) -> UF
+ normalise0: (Z, F, F, SE) -> PSOL
+ normalise : (Z, F, F, F, SE, K, (F, LF) -> U, (F, F) -> UEX) -> PSOL
+ rischDEalg: (Z, F, F, F, K, LK, SE, (F, LF) -> U, (F, F) -> UEX) -> PSOL
+ rischDElog: (LK, RF, RF, SE, K, UP->UP,(F,LF)->U,(F,F)->UEX) -> URF
+ rischDEexp: (LK, RF, RF, SE, K, UP->UP,(F,LF)->U,(F,F)->UEX) -> URF
+ polyDElog : (LK, UP, UP,UP,SE,K,UP->UP,(F,LF)->U,(F,F)->UEX) -> UUP
+ polyDEexp : (LK, UP, UP,UP,SE,K,UP->UP,(F,LF)->U,(F,F)->UEX) -> UUP
+ gpolDEexp : (LK, UP, GP,GP,SE,K,UP->UP,(F,LF)->U,(F,F)->UEX) -> UGP
+ boundAt0 : (LK, F, Z, Z, SE, K, (F, LF) -> U) -> Z
+ boundInf : (LK, F, Z, Z, Z, SE, K, (F, LF) -> U) -> Z
+ logdegrad : (LK, F, UP, Z, SE, K,(F,LF)->U, (F,F) -> UEX) -> UUP
+ expdegrad : (LK, F, UP, Z, SE, K,(F,LF)->U, (F,F) -> UEX) -> UUP
+ logdeg : (UP, F, Z, SE, F, (F, LF) -> U, (F, F) -> UEX) -> UUP
+ expdeg : (UP, F, Z, SE, F, (F, LF) -> U, (F, F) -> UEX) -> UUP
+ exppolyint: (UP, (Z, F) -> PSOL) -> UUP
+ RRF2F : RRF -> F
+ logdiff : (List K, List K) -> List K
+
+ tab:AssociationList(F, Data) := table()
+
+ RF2GP f == (numer(f)::GP exquo denom(f)::GP)::GP
+
+ logdiff(twr, bad) ==
+ [u for u in twr | is?(u, "log"::SE) and not member?(u, bad)]
+
+ rischDEalg(n, nfp, f, g, k, l, x, limint, extint) ==
+ symbolIfCan(kx := ksec(k, l, x)) case SE =>
+ (u := palgRDE(nfp, f, g, kx, k, normal0(n, #1, #2, #3))) case "failed"
+ => [0, 0, false]
+ [u::F, g, true]
+ has?(operator kx, ALGOP) =>
+ rec := primitiveElement(kx::F, k::F)
+ y := rootOf(rec.prim)
+ lk:LK := [kx, k]
+ lv:LF := [(rec.pol1) y, (rec.pol2) y]
+ rc := rischDE(n, eval(f, lk, lv), eval(g, lk, lv), x, limint, extint)
+ rc.sol? => [eval(rc.ans, retract(y)@K, rec.primelt), rc.right, true]
+ [0, 0, false]
+ FAIL
+
+-- solve y' + n f'y = g for a rational function y
+ rischDE(n, f, g, x, limitedint, extendedint) ==
+ zero? g => [0, g, true]
+ zero?(nfp := n * differentiate(f, x)) =>
+ (u := limitedint(g, empty())) case "failed" => [0, 0, false]
+ [u.mainpart, g, true]
+ freeOf?(y := g / nfp, x) => [y, g, true]
+ vl := varselect(union(kernels nfp, kernels g), x)
+ symbolIfCan(k := kmax vl) case SE => normalise0(n, f, g, x)
+ is?(k, "log"::SE) or is?(k, "exp"::SE) =>
+ normalise(n, nfp, f, g, x, k, limitedint, extendedint)
+ has?(operator k, ALGOP) =>
+ rischDEalg(n, nfp, f, g, k, vl, x, limitedint, extendedint)
+ FAIL
+
+ normal0(n, f, g, x) ==
+ rec := normalise0(n, f, g, x)
+ rec.sol? => rec.ans
+ "failed"
+
+-- solve y' + n f' y = g
+-- when f' and g are rational functions over a constant field
+ normalise0(n, f, g, x) ==
+ k := kernel(x)@K
+ if (data1 := search(f, tab)) case "failed" then
+ tab.f := data := makeData(f, x, k)
+ else data := data1::Data
+ f' := nfprime := n * differentiate(f, x)
+ p:P := 1
+ for v in data | (m := n * v.coeff) > 0 repeat
+ p := p * v.argument ** (m::N)
+ f' := f' - m * differentiate(v.argument::F, x) / (v.argument::F)
+ rec := baseRDE(univariate(f', k), univariate(p::F * g, k))
+ y := multivariate(rec.ans, k) / p::F
+ rec.nosol => [y, differentiate(y, x) + nfprime * y, false]
+ [y, g, true]
+
+-- make f weakly normalized, and solve y' + n f' y = g
+ normalise(n, nfp, f, g, x, k, limitedint, extendedint) ==
+ if (data1:= search(f, tab)) case "failed" then
+ tab.f := data := makeData(f, x, k)
+ else data := data1::Data
+ p:P := 1
+ for v in data | (m := n * v.coeff) > 0 repeat
+ p := p * v.argument ** (m::N)
+ f := f - v.coeff * log(v.argument::F)
+ nfp := nfp - m * differentiate(v.argument::F, x) / (v.argument::F)
+ newf := univariate(nfp, k)
+ newg := univariate(p::F * g, k)
+ twr := union(logdiff(tower f, empty()), logdiff(tower g, empty()))
+ ans1 :=
+ is?(k, "log"::SE) =>
+ rischDElog(twr, newf, newg, x, k,
+ differentiate(#1, differentiate(#1, x),
+ differentiate(k::F, x)::UP),
+ limitedint, extendedint)
+ is?(k, "exp"::SE) =>
+ rischDEexp(twr, newf, newg, x, k,
+ differentiate(#1, differentiate(#1, x),
+ monomial(differentiate(first argument k, x), 1)),
+ limitedint, extendedint)
+ ans1 case "failed" => [0, 0, false]
+ [multivariate(ans1::RF, k) / p::F, g, true]
+
+-- find the n * log(P) appearing in f, where P is in P, n in Z
+ makeData(f, x, k) ==
+ disasters := empty()$Data
+ fnum := numer f
+ fden := denom f
+ for u in varselect(kernels f, x) | is?(u, "log"::SE) repeat
+ logand := first argument u
+ if zero?(degree univariate(fden, u)) and
+-- one?(degree(num := univariate(fnum, u))) then
+ (degree(num := univariate(fnum, u)) = 1) then
+ cf := (leadingCoefficient num) / fden
+ if (n := retractIfCan(cf)@Union(Z, "failed")) case Z then
+ if degree(numer logand, k) > 0 then
+ disasters := concat([n::Z, numer logand], disasters)
+ if degree(denom logand, k) > 0 then
+ disasters := concat([-(n::Z), denom logand], disasters)
+ disasters
+
+ rischDElog(twr, f, g, x, theta, driv, limint, extint) ==
+ (u := monomRDE(f, g, driv)) case "failed" => "failed"
+ (v := polyDElog(twr, u.a, retract(u.b), retract(u.c), x, theta, driv,
+ limint, extint)) case "failed" => "failed"
+ v::UP / u.t
+
+ rischDEexp(twr, f, g, x, theta, driv, limint, extint) ==
+ (u := monomRDE(f, g, driv)) case "failed" => "failed"
+ (v := gpolDEexp(twr, u.a, RF2GP(u.b), RF2GP(u.c), x, theta, driv,
+ limint, extint)) case "failed" => "failed"
+ convert(v::GP)@RF / u.t::RF
+
+ polyDElog(twr, aa, bb, cc, x, t, driv, limint, extint) ==
+ zero? cc => 0
+ t' := differentiate(t::F, x)
+ zero? bb =>
+ (u := cc exquo aa) case "failed" => "failed"
+ primintfldpoly(u::UP, extint(#1, t'), t')
+ n := degree(cc)::Z - (db := degree(bb)::Z)
+ if ((da := degree(aa)::Z) = db) and (da > 0) then
+ lk0 := tower(f0 :=
+ - (leadingCoefficient bb) / (leadingCoefficient aa))
+ lk1 := logdiff(twr, lk0)
+ (if0 := limint(f0, [first argument u for u in lk1]))
+ case "failed" => error "Risch's theorem violated"
+ (alph := validExponential(lk0, RRF2F(if0::RRF), x)) case F =>
+ return
+ (ans := polyDElog(twr, alph::F * aa,
+ differentiate(alph::F, x) * aa + alph::F * bb,
+ cc, x, t, driv, limint, extint)) case "failed" => "failed"
+ alph::F * ans::UP
+ if (da > db + 1) then n := max(0, degree(cc)::Z - da + 1)
+ if (da = db + 1) then
+ i := limint(- (leadingCoefficient bb) / (leadingCoefficient aa),
+ [first argument t])
+ if not(i case "failed") then
+ r :=
+ null(i.limitedlogs) => 0$F
+ i.limitedlogs.first.coeff
+ if (nn := retractIfCan(r)@Union(Z, "failed")) case Z then
+ n := max(nn::Z, n)
+ (v := polyRDE(aa, bb, cc, n, driv)) case ans =>
+ v.ans.nosol => "failed"
+ v.ans.ans
+ w := v.eq
+ zero?(w.b) =>
+ degree(w.c) > w.m => "failed"
+ (u := primintfldpoly(w.c, extint(#1,t'), t')) case "failed" => "failed"
+ degree(u::UP) > w.m => "failed"
+ w.alpha * u::UP + w.beta
+ (u := logdegrad(twr, retract(w.b), w.c, w.m, x, t, limint, extint))
+ case "failed" => "failed"
+ w.alpha * u::UP + w.beta
+
+ gpolDEexp(twr, a, b, c, x, t, driv, limint, extint) ==
+ zero? c => 0
+ zero? b =>
+ (u := c exquo (a::GP)) case "failed" => "failed"
+ expintfldpoly(u::GP,
+ rischDE(#1, first argument t, #2, x, limint, extint))
+ lb := boundAt0(twr, - coefficient(b, 0) / coefficient(a, 0),
+ nb := order b, nc := order c, x, t, limint)
+ tm := monomial(1, (m := max(0, max(-nb, lb - nc)))::N)$UP
+ (v := polyDEexp(twr,a * tm,lb * differentiate(first argument t, x)
+ * a * tm + retract(b * tm::GP)@UP,
+ retract(c * monomial(1, m - lb))@UP,
+ x, t, driv, limint, extint)) case "failed" => "failed"
+ v::UP::GP * monomial(1, lb)
+
+ polyDEexp(twr, aa, bb, cc, x, t, driv, limint, extint) ==
+ zero? cc => 0
+ zero? bb =>
+ (u := cc exquo aa) case "failed" => "failed"
+ exppolyint(u::UP, rischDE(#1, first argument t, #2, x, limint, extint))
+ n := boundInf(twr,-leadingCoefficient(bb) / (leadingCoefficient aa),
+ degree(aa)::Z, degree(bb)::Z, degree(cc)::Z, x, t, limint)
+ (v := polyRDE(aa, bb, cc, n, driv)) case ans =>
+ v.ans.nosol => "failed"
+ v.ans.ans
+ w := v.eq
+ zero?(w.b) =>
+ degree(w.c) > w.m => "failed"
+ (u := exppolyint(w.c,
+ rischDE(#1, first argument t, #2, x, limint, extint)))
+ case "failed" => "failed"
+ w.alpha * u::UP + w.beta
+ (u := expdegrad(twr, retract(w.b), w.c, w.m, x, t, limint, extint))
+ case "failed" => "failed"
+ w.alpha * u::UP + w.beta
+
+ exppolyint(p, rischdiffeq) ==
+ (u := expintfldpoly(p::GP, rischdiffeq)) case "failed" => "failed"
+ retractIfCan(u::GP)@Union(UP, "failed")
+
+ boundInf(twr, f0, da, db, dc, x, t, limitedint) ==
+ da < db => dc - db
+ da > db => max(0, dc - da)
+ l1 := logdiff(twr, l0 := tower f0)
+ (if0 := limitedint(f0, [first argument u for u in l1]))
+ case "failed" => error "Risch's theorem violated"
+ (alpha := validExponential(concat(t, l0), RRF2F(if0::RRF), x))
+ case F =>
+ al := separate(univariate(alpha::F, t))$GP
+ zero?(al.fracPart) and monomial?(al.polyPart) =>
+ max(0, max(degree(al.polyPart), dc - db))
+ dc - db
+ dc - db
+
+ boundAt0(twr, f0, nb, nc, x, t, limitedint) ==
+ nb ^= 0 => min(0, nc - min(0, nb))
+ l1 := logdiff(twr, l0 := tower f0)
+ (if0 := limitedint(f0, [first argument u for u in l1]))
+ case "failed" => error "Risch's theorem violated"
+ (alpha := validExponential(concat(t, l0), RRF2F(if0::RRF), x))
+ case F =>
+ al := separate(univariate(alpha::F, t))$GP
+ zero?(al.fracPart) and monomial?(al.polyPart) =>
+ min(0, min(degree(al.polyPart), nc))
+ min(0, nc)
+ min(0, nc)
+
+-- case a = 1, deg(B) = 0, B <> 0
+-- cancellation at infinity is possible
+ logdegrad(twr, b, c, n, x, t, limitedint, extint) ==
+ t' := differentiate(t::F, x)
+ lk1 := logdiff(twr, lk0 := tower(f0 := - b))
+ (if0 := limitedint(f0, [first argument u for u in lk1]))
+ case "failed" => error "Risch's theorem violated"
+ (alpha := validExponential(lk0, RRF2F(if0::RRF), x)) case F =>
+ (u1 := primintfldpoly(inv(alpha::F) * c, extint(#1, t'), t'))
+ case "failed" => "failed"
+ degree(u1::UP)::Z > n => "failed"
+ alpha::F * u1::UP
+ logdeg(c, - if0.mainpart -
+ +/[v.coeff * log(v.logand) for v in if0.limitedlogs],
+ n, x, t', limitedint, extint)
+
+-- case a = 1, degree(b) = 0, and (exp integrate b) is not in F
+-- this implies no cancellation at infinity
+ logdeg(c, f, n, x, t', limitedint, extint) ==
+ answr:UP := 0
+ repeat
+ zero? c => return answr
+ (n < 0) or ((m := degree c)::Z > n) => return "failed"
+ u := rischDE(1, f, leadingCoefficient c, x, limitedint, extint)
+ ~u.sol? => return "failed"
+ zero? m => return(answr + u.ans::UP)
+ n := m::Z - 1
+ c := (reductum c) - monomial(m::Z * t' * u.ans, (m - 1)::N)
+ answr := answr + monomial(u.ans, m)
+
+-- case a = 1, deg(B) = 0, B <> 0
+-- cancellation at infinity is possible
+ expdegrad(twr, b, c, n, x, t, limint, extint) ==
+ lk1 := logdiff(twr, lk0 := tower(f0 := - b))
+ (if0 := limint(f0, [first argument u for u in lk1]))
+ case "failed" => error "Risch's theorem violated"
+ intf0 := - if0.mainpart -
+ +/[v.coeff * log(v.logand) for v in if0.limitedlogs]
+ (alpha := validExponential(concat(t, lk0), RRF2F(if0::RRF), x))
+ case F =>
+ al := separate(univariate(alpha::F, t))$GP
+ zero?(al.fracPart) and monomial?(al.polyPart) and
+ (degree(al.polyPart) >= 0) =>
+ (u1 := expintfldpoly(c::GP * recip(al.polyPart)::GP,
+ rischDE(#1, first argument t, #2, x, limint, extint)))
+ case "failed" => "failed"
+ degree(u1::GP) > n => "failed"
+ retractIfCan(al.polyPart * u1::GP)@Union(UP, "failed")
+ expdeg(c, intf0, n, x, first argument t, limint,extint)
+ expdeg(c, intf0, n, x, first argument t, limint, extint)
+
+-- case a = 1, degree(b) = 0, and (exp integrate b) is not a monomial
+-- this implies no cancellation at infinity
+ expdeg(c, f, n, x, eta, limitedint, extint) ==
+ answr:UP := 0
+ repeat
+ zero? c => return answr
+ (n < 0) or ((m := degree c)::Z > n) => return "failed"
+ u := rischDE(1, f + m * eta, leadingCoefficient c, x,limitedint,extint)
+ ~u.sol? => return "failed"
+ zero? m => return(answr + u.ans::UP)
+ n := m::Z - 1
+ c := reductum c
+ answr := answr + monomial(u.ans, m)
+
+ RRF2F rrf ==
+ rrf.mainpart + +/[v.coeff*log(v.logand) for v in rrf.limitedlogs]
+
+@
+\section{License}
+<<license>>=
+--Copyright (c) 1991-2002, The Numerical ALgorithms Group Ltd.
+--All rights reserved.
+--
+--Redistribution and use in source and binary forms, with or without
+--modification, are permitted provided that the following conditions are
+--met:
+--
+-- - Redistributions of source code must retain the above copyright
+-- notice, this list of conditions and the following disclaimer.
+--
+-- - Redistributions in binary form must reproduce the above copyright
+-- notice, this list of conditions and the following disclaimer in
+-- the documentation and/or other materials provided with the
+-- distribution.
+--
+-- - Neither the name of The Numerical ALgorithms Group Ltd. nor the
+-- names of its contributors may be used to endorse or promote products
+-- derived from this software without specific prior written permission.
+--
+--THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+--IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+--TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+--PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
+--OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+--EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+--PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+--PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+--LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+--NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+--SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+@
+<<*>>=
+<<license>>
+
+-- SPAD files for the integration world should be compiled in the
+-- following order:
+--
+-- intaux rderf intrf curve curvepkg divisor pfo
+-- intalg intaf efstruc RDEEF intef irexpand integrat
+
+<<package INTTOOLS IntegrationTools>>
+<<package RDEEF ElementaryRischDE>>
+@
+\eject
+\begin{thebibliography}{99}
+\bibitem{1} nothing
+\end{thebibliography}
+\end{document}