)abbrev package INEP InnerNumericEigenPackage
++ Author: P. Gianni
++ Date Created: Summer 1990
++ Basic Functions:
++ Related Constructors: ModularField
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ This package is the inner package to be used by NumericRealEigenPackage
++ and NumericComplexEigenPackage for the computation of numeric
++ eigenvalues and eigenvectors.
InnerNumericEigenPackage(K, F, Par) : C == T
 where
   F    :   Field  -- this is the field where the answer will be
                   -- for dealing with the complex case
   K    :   Field  -- type of the  input
   Par  :   Join(Field, OrderedRing)  -- it will be NF or RN

   SY    ==> Symbol()
   RN    ==> Fraction Integer
   I     ==> Integer
   NF    ==> Float
   CF    ==> Complex Float
   GRN   ==> Complex RN
   GI    ==> Complex Integer
   PI    ==> PositiveInteger
   NNI   ==> NonNegativeInteger
   MRN   ==> Matrix RN

   MK          ==> Matrix K
   PK          ==> Polynomial K
   MF          ==> Matrix F
   SUK         ==> SparseUnivariatePolynomial K
   SUF         ==> SparseUnivariatePolynomial F
   SUP         ==> SparseUnivariatePolynomial
   MSUK        ==> Matrix SUK

   PEigenForm  ==> Record(algpol : SUK, almult : Integer, poleigen : List(MSUK))

   outForm     ==> Record(outval : F, outmult : Integer, outvect : List MF)

   IntForm     ==> Union(outForm, PEigenForm)
   UFactor     ==> (SUK -> Factored SUK)
   C == with

     charpol  :  MK   ->  SUK
       ++ charpol(m) computes the characteristic polynomial of a matrix
       ++ m with entries in K.

     solve1   : (SUK, Par) -> List F
       ++ solve1(pol, eps) finds the roots of the univariate polynomial
       ++ polynomial pol to precision eps. If K is \spad{Fraction Integer}
       ++ then only the real roots are returned, if K is
       ++ \spad{Complex Fraction Integer} then all roots are found.

     innerEigenvectors    : (MK, Par, UFactor)   ->  List(outForm)
       ++ innerEigenvectors(m, eps, factor) computes explicitly
       ++ the eigenvalues and the correspondent eigenvectors
       ++ of the matrix m. The parameter eps determines the type of
       ++ the output, factor is the univariate factorizer used
       ++ to reduce the characteristic polynomial into irreducible factors.

   T == add

     numeric(r : K) : F ==
       K is RN =>
         F is NF => convert(r)$RN
         F is RN    => r
         F is CF    => r :: RN :: CF
         F is GRN   => r::RN::GRN
       K is GRN =>
         F is GRN => r
         F is CF  => convert(convert r)
       error "unsupported coefficient type"

    ---- next functions needed for defining  ModularField ----

     monicize(f : SUK) : SUK ==
       (a := leadingCoefficient f) =1 => f
       inv(a)*f

     reduction(u : SUK, p : SUK) : SUK == u rem p

     merge(p:SUK,q:SUK):Union(SUK,"failed") ==
         p = q => p
         p = 0 => q
         q = 0 => p
         "failed"

     exactquo(u:SUK,v:SUK,p:SUK):Union(SUK,"failed") ==
        val := extendedEuclidean(v, p, u)
        val case "failed" => "failed"
        val.coef1

         ----  eval a vector of F in a radical expression  ----
     evalvect(vect : MSUK, alg : F) : MF ==
       n := nrows vect
       w : MF := zero(n, 1)$MF
       for i in 1..n repeat
         polf := map(numeric,
           vect(i, 1))$UnivariatePolynomialCategoryFunctions2(K, SUK, F, SUF)
         v : F := elt(polf, alg)
         setelt!(w, i, 1, v)
       w

       ---- internal function for the computation of eigenvectors  ----
     inteigen(A : MK, p : SUK, fact : UFactor) : List(IntForm) ==
       dimA : NNI :=  nrows A
       MM := ModularField(SUK, SUK, reduction, merge, exactquo)
       AM := Matrix(MM)
       lff := factorList fact(p)
       res : List IntForm  := []
       lr : List MF := []
       for ff in lff repeat
         pol : SUK := ff.factor
         if (degree pol)=1 then
           alpha : K := -coefficient(pol, 0)/leadingCoefficient pol
           -- compute the eigenvectors, rational case
           B1 : MK := zero(dimA, dimA)$MK
           for i in 1..dimA repeat
             for j in 1..dimA repeat B1(i, j) := A(i, j)
             B1(i, i) := B1(i, i) - alpha
           lr := []
           for vecr in nullSpace B1 repeat
             wf : MF := zero(dimA, 1)
             for i in 1..dimA repeat wf(i, 1) := numeric vecr.i
             lr := cons(wf, lr)
           res := cons([numeric alpha, ff.exponent, lr]$outForm, res)
         else
           ppol := monicize pol
           alg : MM := reduce(monomial(1, 1), ppol)
           B : AM := zero(dimA, dimA)$AM
           for i in 1..dimA  repeat
             for j in 1..dimA repeat B(i, j) := reduce(A(i, j) ::SUK, ppol)
             B(i, i) := B(i, i) - alg
           sln2 := nullSpace B
           soln : List MSUK := []
           for vec in sln2 repeat
             wk : MSUK := zero(dimA, 1)
             for i in 1..dimA repeat wk(i, 1) := (vec.i)::SUK
             soln := cons(wk, soln)
           res := cons([ff.factor, ff.exponent, soln]$PEigenForm,
                            res)
       res

     if K is RN then
         solve1(up : SUK, eps : Par) : List(F) ==
           denom := "lcm"/[denom(c::RN) for c in coefficients up]
           up := denom*up
           upi : SUP(I) := map(numer,
                               up)$UnivariatePolynomialCategoryFunctions2(
                                    RN, SUP RN, I, SUP I)
           innerSolve1(upi, eps)$InnerNumericFloatSolvePackage(I, F, Par)
     else if K is GRN then
         solve1(up : SUK, eps : Par) : List(F) ==
           denom := "lcm"/[lcm(denom real(c::GRN), denom imag(c::GRN))
                                for c in coefficients up]
           up := denom*up
           upgi := map((c1 : GRN) : GI +-> complex(numer(real c1), numer(imag c1)),
                      up)$UnivariatePolynomialCategoryFunctions2(GRN, SUP GRN, GI, SUP GI)
           innerSolve1(upgi, eps)$InnerNumericFloatSolvePackage(GI, F, Par)
     else error "unsupported matrix type"

          ----  the real eigenvectors expressed as floats  ----

     innerEigenvectors(A : MK, eps : Par, fact : UFactor) : List outForm ==
       pol := charpol A
       sln1 : List(IntForm) := inteigen(A, pol, fact)
       sln : List(outForm) := []
       for lev in sln1 repeat
         lev case outForm => sln := cons(lev, sln)
         leva := lev@PEigenForm
         lval : List(F) := solve1(leva.algpol, eps)
         lvect := leva.poleigen
         lmult := leva.almult
         for alg in lval repeat
           nsl := [alg, lmult, [evalvect(ep, alg) for ep in lvect]]$outForm
           sln := cons(nsl, sln)
       sln

     charpol(A : MK) : SUK ==
       dimA := (nrows A)
       dimA ~= ncols A => error " The matrix is not square"
       B : Matrix SUK := zero(dimA, dimA)
       for i in 1..dimA repeat
         for j in 1..dimA repeat  B(i, j) := A(i, j)::SUK
         B(i, i) := B(i, i) - monomial(1, 1)$SUK
       determinant B


)abbrev package NREP NumericRealEigenPackage
++ Author: P. Gianni
++ Date Created: Summer 1990
++ Basic Functions:
++ Related Constructors: FloatingRealPackage
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ This package computes explicitly eigenvalues and eigenvectors of
++ matrices with entries over the Rational Numbers.
++ The results are expressed as floating numbers or as rational numbers
++ depending on the type of the parameter Par.
NumericRealEigenPackage(Par) : C == T
 where
   Par   :   Join(Field, OrderedRing) -- Float or RationalNumber

   SY    ==> Symbol()
   RN    ==> Fraction Integer
   I     ==> Integer
   NF    ==> Float
   CF    ==> Complex Float
   GRN   ==> Complex RN
   GI    ==> Complex Integer
   PI    ==> PositiveInteger
   NNI   ==> NonNegativeInteger
   MRN   ==> Matrix RN

   MPar        ==> Matrix Par
   outForm     ==> Record(outval : Par, outmult : Integer, outvect : List MPar)

   C == with
     characteristicPolynomial :   MRN    -> Polynomial RN
       ++ characteristicPolynomial(m) returns the characteristic polynomial
       ++ of the matrix m expressed as polynomial
       ++ over RN with a new symbol as variable.
     characteristicPolynomial : (MRN, SY) -> Polynomial RN
       ++ characteristicPolynomial(m, x) returns the characteristic polynomial
       ++ of the matrix m expressed as polynomial
       ++ over RN with variable x.
     realEigenvalues  :   (MRN, Par)   ->  List Par
       ++ realEigenvalues(m, eps) computes the eigenvalues of the matrix
       ++ m to precision eps. The eigenvalues are expressed as floats or
       ++ rational numbers depending on the type of eps (float or rational).
     realEigenvectors    : (MRN, Par)   ->  List(outForm)
       ++ realEigenvectors(m, eps)  returns a list of
       ++ records each one containing
       ++ a real eigenvalue, its algebraic multiplicity, and a list of
       ++ associated eigenvectors. All these results
       ++ are computed to precision eps as floats or rational
       ++ numbers depending on the type of eps .


   T == add

     import from InnerNumericEigenPackage(RN, Par, Par)

     characteristicPolynomial(m : MRN) : Polynomial RN ==
       x : SY := new()$SY
       multivariate(charpol(m), x)

            ----  characteristic polynomial of a matrix A ----
     characteristicPolynomial(A : MRN, x : SY) : Polynomial RN ==
       multivariate(charpol(A), x)

     realEigenvalues(m : MRN, eps : Par) : List Par  ==
       solve1(charpol m, eps)

     realEigenvectors(m : MRN, eps : Par) : List outForm ==
       innerEigenvectors(m, eps, factorPolynomial$RN)

)abbrev package NCEP NumericComplexEigenPackage
++ Author: P. Gianni
++ Date Created: Summer 1990
++ Basic Functions:
++ Related Constructors: FloatingComplexPackage
++ Also See:
++ AMS Classifications:
++ Keywords:
++ References:
++ Description:
++ This package computes explicitly eigenvalues and eigenvectors of
++ matrices with entries over the complex rational numbers.
++ The results are expressed either as complex floating numbers or as
++ complex rational numbers
++ depending on the type of the precision parameter.
NumericComplexEigenPackage(Par) : C == T
 where
   Par   :   Join(Field, OrderedRing)   -- Float or RationalNumber

   SY    ==> Symbol()
   RN    ==> Fraction Integer
   I     ==> Integer
   NF    ==> Float
   CF    ==> Complex Float
   GRN   ==> Complex RN
   GI    ==> Complex Integer
   PI    ==> PositiveInteger
   NNI   ==> NonNegativeInteger
   MRN   ==> Matrix RN

   MCF         ==> Matrix CF
   MGRN        ==> Matrix GRN
   MCPar       ==> Matrix Complex Par
   outForm     ==> Record(outval : Complex Par, outmult : Integer, outvect : List MCPar)

   C == with
     characteristicPolynomial :   MGRN    -> Polynomial GRN
       ++ characteristicPolynomial(m) returns the characteristic polynomial
       ++ of the matrix m expressed as polynomial
       ++ over complex rationals with a new symbol as variable.
     characteristicPolynomial : (MGRN, SY) -> Polynomial GRN
       ++ characteristicPolynomial(m, x) returns the characteristic polynomial
       ++ of the matrix m expressed as polynomial
       ++ over Complex Rationals with variable x.
     complexEigenvalues  :   (MGRN, Par)   ->  List Complex Par
       ++ complexEigenvalues(m, eps) computes the eigenvalues of the matrix
       ++ m to precision eps. The eigenvalues are expressed as complex floats or
       ++ complex rational numbers depending on the type of eps (float or rational).
     complexEigenvectors    : (MGRN, Par)   ->  List(outForm)
       ++ complexEigenvectors(m, eps)  returns a list of
       ++ records each one containing
       ++ a complex eigenvalue, its algebraic multiplicity, and a list of
       ++ associated eigenvectors. All these results
       ++ are computed to precision eps and are expressed as complex floats
       ++ or complex rational numbers depending on the type of eps (float or rational).
   T == add

     import from InnerNumericEigenPackage(GRN, Complex Par, Par)

     characteristicPolynomial(m : MGRN) : Polynomial GRN  ==
       x : SY := new()$SY
       multivariate(charpol m, x)

            ----  characteristic polynomial of a matrix A ----
     characteristicPolynomial(A : MGRN, x : SY) : Polynomial GRN ==
       multivariate(charpol A, x)

     complexEigenvalues(m : MGRN, eps : Par) : List Complex Par  ==
       solve1(charpol m, eps)

     complexEigenvectors(m : MGRN, eps : Par) : List outForm ==
       innerEigenvectors(m, eps, factorPolynomial$GRN)

--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
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--
--    - 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
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