MathAction DistributedExpression

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Francois Maltey (FM) and Bill Page (BP) wrote:

  How can I persuade FriCAS to write out

fricas

(1) -> ex1:=(2*log(x)+3*exp(y))*(4*sin(z)+2*log(x))

$\label{eq1}{{\left({8 \ {\log \left({x}\right)}}+{{12}\ {{e}^{y}}}\right)}\ {\sin \left({z}\right)}}+{4 \ {{\log \left({x}\right)}^{2}}}+{6 \ {{e}^{y}}\ {\log \left({x}\right)}}$

(1)

Type: Expression(Integer)

as a "sum of products"? E.g.

fricas

)set output algebra on

ex2:=box(8*log(x)*sin(z))+box(4*log(x)^2)+box(12*exp(y)*sin(z))+box(6*exp(y)*log(x))

                              y                 2       y
   (2)  8 log(x)sin(z) + 12 %e sin(z) + 4 log(x)  + 6 %e log(x)

$\label{eq2}{\left({8 \ {\log \left({x}\right)}\ {\sin \left({z}\right)}}\right)}+{\left({{12}\ {{e}^{y}}\ {\sin \left({z}\right)}}\right)}+{\left({4 \ {{\log \left({x}\right)}^{2}}}\right)}+{\left({6 \ {{e}^{y}}\ {\log \left({x}\right)}}\right)}$

(2)

Type: Expression(Integer)

fricas

)set output algebra off

In FriCAS, without box both of these expressions are rendered the same!

On Tuesday, September 20, 2005 8:20 AM Martin Rubey wrote:

For example:

fricas

subst(ex1, kernels ex1, [x1,x2,x3])::DMP([x1,x2,x3], INT)

$\label{eq3}{8 \ x 1 \ x 2}+{{12}\ x 1 \ x 3}+{4 \ {{x 2}^{2}}}+{6 \ x 2 \ x 3}$

(3)

Type: DistributedMultivariatePolynomial?([x1,x2,x3],Integer)

FM:

  Can I substitute theses elementary functions [kernels] to new variables, make
  transforms over polynoms,

yes...

FM:

  and substitute the variables back ?

Well, as soon as you go back, you'll loose the transformations you did...

The "deeper" reason why there is no domain DistributedExpression is probably that DMP defined in gdpoly.spad asks for a List Symbol as variables. It probably could be in fact any finite OrderedSet, but it would need some work to get it done:

fricas

List Kernel Expression Integer has OrderedSet

$\label{eq4} \mbox{\rm true}$

(4)

Type: Boolean

A simple workaround is:

fricas

out(p, kl, vl) == 
  if reductum p = 0 
  then (eval(leadingMonomial(p)::EXPR INT, vl, kl))::OUTFORM
  else (eval(leadingMonomial(p)::EXPR INT, vl, kl))::OUTFORM _
       + out(reductum p, kl, vl)

Type: Void

fricas

output ex == 
  kl := kernels ex
  vl := [subscript('x, [i::OutputForm]) for i in 1..#kl]
  out(subst(ex, kl, vl)::DMP(vl, INT), kl, vl)

Type: Void

fricas

output(ex1)

   Cannot compile conversion for types involving local variables. In 
      particular, could not compile the expression involving :: DMP(vl,
      INT) 
   FriCAS will attempt to step through and interpret the code.

fricas

Compiling function out with type (DistributedMultivariatePolynomial(
      [x[1],x[2],x[3]],Integer), List(Kernel(Expression(Integer))), 
      List(Symbol)) -> OutputForm

$\label{eq5}{8 \ {\log \left({x}\right)}\ {\sin \left({z}\right)}}+{{12}\ {{e}^{y}}\ {\sin \left({z}\right)}}+{4 \ {{\log \left({x}\right)}^{2}}}+{6 \ {{e}^{y}}\ {\log \left({x}\right)}}$

(5)

Type: OutputForm?

Note that this returns an element of OUTFORM. This can be circumvented: highly undebugged, undocumented and all the bad things :-)

spad

)abb domain DEXPR DistributedExpression
DistributedExpression(R: Join(Ring, OrderedSet)): Exports == Implementation where
  EXPRR ==> Expression R
  AN    ==> AlgebraicNumber
  SUP   ==> SparseUnivariatePolynomial

  Exports == FunctionSpace R with
    if R has IntegralDomain then
      AlgebraicallyClosedFunctionSpace R
      TranscendentalFunctionCategory
      CombinatorialOpsCategory
      LiouvillianFunctionCategory
      SpecialFunctionCategory
      reduce: % -> %
        ++ reduce(f) simplifies all the unreduced algebraic quantities
        ++ present in f by applying their defining relations.
      number?: % -> Boolean
        ++ number?(f) tests if f is rational
      simplifyPower: (%,Integer) -> %
        ++ simplifyPower?(f,n) \undocumented{}
      if R has GcdDomain then
        factorPolynomial : SUP  % -> Factored SUP %
           ++ factorPolynomial(p) \undocumented{}
        squareFreePolynomial : SUP % -> Factored SUP %
           ++ squareFreePolynomial(p) \undocumented{}
      if R has RetractableTo Integer then RetractableTo AN

    coerce: EXPRR -> %

  Implementation == EXPRR add

    Rep := EXPRR

    out: (Polynomial R, List %, List %) -> OutputForm 
-- coerces the polynomial to OutputForm completely expanded and replaces the
-- variables in vl with the kernels in kl
    out(p, kl, vl) == 
      ex := leadingMonomial(p)::%
      if reductum p = 0 
      then coerce(eval(ex, vl, kl))$Rep
      else coerce(eval(ex, vl, kl))$Rep _
           + out(reductum p, kl, vl)

    coerce(ex:%):OutputForm == 
      kl := kernels ex
      vl: List % := [subscript('x, [i::OutputForm])::Symbol::% for i in 1..#kl]
      ex1: % := subst(ex, kl, vl)$%
      kl1 := map(coerce(#1)$%, kl)$ListFunctions2(Kernel %, %)
      if R has IntegralDomain then
        if denominator ex1 = 1 then
          out(retract(numerator ex1)@Polynomial(R), kl1, vl)
        else
          out(retract(numerator ex1)@Polynomial(R), kl1, vl)
            / out(retract(denominator ex1)@Polynomial(R), kl1, vl)
      else
        out(retract(ex1)@Polynomial(R), kl1, vl)

    coerce(p:EXPRR):% == p

spad

   Compiling FriCAS source code from file 
      /var/lib/zope2.10/instance/axiom-wiki/var/LatexWiki/4397718924680446687-25px007.spad
      using old system compiler.
   DEXPR abbreviates domain DistributedExpression 
------------------------------------------------------------------------
   initializing NRLIB DEXPR for DistributedExpression 
   compiling into NRLIB DEXPR 
****** Domain: R already in scope
   compiling local out : (Polynomial R,List %,List %) -> OutputForm
Time: 0.03 SEC.

   compiling exported coerce : % -> OutputForm
****** Domain: R already in scope
augmenting R: (IntegralDomain)
Time: 0.01 SEC.

   compiling exported coerce : Expression R -> %
      DEXPR;coerce;E%;3 is replaced by p 
Time: 0 SEC.

****** Domain: % already in scope
augmenting %: (RetractableTo (Integer))
****** Domain: R already in scope
augmenting R: (IntegralDomain)
****** Domain: R already in scope
augmenting R: (GcdDomain)
****** Domain: R already in scope
augmenting R: (IntegralDomain)
****** Domain: R already in scope
augmenting R: (RetractableTo (Integer))
****** Domain: R already in scope
augmenting R: (LinearlyExplicitOver (Integer))
****** Domain: % already in scope
augmenting %: (RetractableTo (Integer))
****** Domain: R already in scope
augmenting R: (CharacteristicNonZero)
****** Domain: R already in scope
augmenting R: (CommutativeRing)
****** Domain: R already in scope
augmenting R: (ConvertibleTo (InputForm))
****** Domain: R already in scope
augmenting R: (ConvertibleTo (Pattern (Float)))
****** Domain: R already in scope
augmenting R: (ConvertibleTo (Pattern (Integer)))
****** Domain: R already in scope
augmenting R: (Group)
****** Domain: R already in scope
augmenting R: (IntegralDomain)
****** Domain: R already in scope
augmenting R: (PatternMatchable (Float))
****** Domain: R already in scope
augmenting R: (PatternMatchable (Integer))
****** Domain: R already in scope
augmenting R: (RetractableTo (Integer))
(time taken in buildFunctor:  74177)

;;;     ***       |DistributedExpression| REDEFINED

;;;     ***       |DistributedExpression| REDEFINED
Time: 0.11 SEC.

   Warnings: 
      [1] coerce:  $$ has no value

   Cumulative Statistics for Constructor DistributedExpression
      Time: 0.16 seconds

--------------non extending category----------------------
.. DistributedExpression(#1) of cat 
(|Join| (|FunctionSpace| |#1|)
        (CATEGORY |domain|
         (IF (|has| |#1| (|IntegralDomain|))
             (PROGN
              (ATTRIBUTE (|AlgebraicallyClosedFunctionSpace| |#1|))
              (ATTRIBUTE (|TranscendentalFunctionCategory|))
              (ATTRIBUTE (|CombinatorialOpsCategory|))
              (ATTRIBUTE (|LiouvillianFunctionCategory|))
              (ATTRIBUTE (|SpecialFunctionCategory|))
              (SIGNATURE |reduce| (% %))
              (SIGNATURE |number?| ((|Boolean|) %))
              (SIGNATURE |simplifyPower| (% % (|Integer|)))
              (IF (|has| |#1| (|GcdDomain|))
                  (PROGN
                   (SIGNATURE |factorPolynomial|
                    ((|Factored| (|SparseUnivariatePolynomial| %))
                     (|SparseUnivariatePolynomial| %)))
                   (SIGNATURE |squareFreePolynomial|
                    ((|Factored| (|SparseUnivariatePolynomial| %))
                     (|SparseUnivariatePolynomial| %))))
                  |noBranch|)
              (IF (|has| |#1| (|RetractableTo| (|Integer|)))
                  (ATTRIBUTE (|RetractableTo| (|AlgebraicNumber|)))
                  |noBranch|))
             |noBranch|)
         (SIGNATURE |coerce| (% (|Expression| |#1|)))))   has no 
(IF (|has| |#1| (|IntegralDomain|))
    (PROGN
     (ATTRIBUTE (|AlgebraicallyClosedFunctionSpace| |#1|))
     (ATTRIBUTE (|TranscendentalFunctionCategory|))
     (ATTRIBUTE (|CombinatorialOpsCategory|))
     (ATTRIBUTE (|LiouvillianFunctionCategory|))
     (ATTRIBUTE (|SpecialFunctionCategory|))
     (SIGNATURE |reduce| (% %))
     (SIGNATURE |number?| ((|Boolean|) %))
     (IF (|has| |#1| (|PolynomialFactorizationExplicit|))
         (ATTRIBUTE (|PolynomialFactorizationExplicit|))
         |noBranch|)
     (SIGNATURE |setSimplifyDenomsFlag| ((|Boolean|) (|Boolean|)))
     (SIGNATURE |getSimplifyDenomsFlag| ((|Boolean|))))
    |noBranch|)    finalizing NRLIB DEXPR 
   Processing DistributedExpression for Browser database:
--->-->DistributedExpression(constructor): Not documented!!!!
--------(reduce (% %))---------
--------(number? ((Boolean) %))---------
--------(simplifyPower (% % (Integer)))---------
--->-->DistributedExpression((simplifyPower (% % (Integer)))): Improper first word in comments: simplifyPower?
"simplifyPower?(\\spad{f},{}\\spad{n}) \\undocumented{}"
--------(factorPolynomial ((Factored (SparseUnivariatePolynomial %)) (SparseUnivariatePolynomial %)))---------
--------(squareFreePolynomial ((Factored (SparseUnivariatePolynomial %)) (SparseUnivariatePolynomial %)))---------
--->-->DistributedExpression((coerce (% (Expression R)))): Not documented!!!!
--->-->DistributedExpression(): Missing Description
; compiling file "/var/aw/var/LatexWiki/DEXPR.NRLIB/DEXPR.lsp" (written 31 OCT 2024 07:19:20 PM):

; wrote /var/aw/var/LatexWiki/DEXPR.NRLIB/DEXPR.fasl
; compilation finished in 0:00:00.020
------------------------------------------------------------------------
   DistributedExpression is now explicitly exposed in frame initial 
   DistributedExpression will be automatically loaded when needed from 
      /var/aw/var/LatexWiki/DEXPR.NRLIB/DEXPR

Unfortunately, it seems that it is not possible to tell FriCAS to take all the exported functions of a given domain and export them. So we have to include the whole Exports section of EXPR...

fricas

ex1::DistributedExpression(Integer)

$\label{eq6}{6 \ {x_{3}}\ {\sin \left({z}\right)}}+{{12}\ {x_{1}}\ {x_{3}}}+{4 \ {{\sin \left({z}\right)}^{2}}}+{8 \ {x_{1}}\ {\sin \left({z}\right)}}$

(6)

Type: DistributedExpression(Integer)

fricas

((1+2*a+3*b)*(4*c+5*d))::DEXPR INT

$\label{eq7}{8 \ {x_{4}}\ d}+{{10}\ {x_{1}}\ {x_{4}}}+{{12}\ {x_{3}}\ d}+{{15}\ {x_{1}}\ {x_{3}}}+{4 \ d}+{5 \ {x_{1}}}$

(7)

Type: DistributedExpression(Integer)

fricas

%::POLY INT

$\label{eq8}{{\left({{15}\ b}+{{10}\ a}+ 5 \right)}\ d}+{{\left({{12}\ b}+{8 \ a}+ 4 \right)}\ c}$

(8)

Type: Polynomial(Integer)

duplicate exported functions --Bill Page, Tue, 20 Sep 2005 11:45:30 -0500 reply

Unfortunately, it seems that it is not possible to tell Axiom to take all the exported functions of a given domain and export them.

Isn't this a case where one should define a category relevant to both Expression and DistributedExpression in order to avoid duplication of the list of exports?

... --kratt6, Mon, 26 Sep 2005 08:14:17 -0500 reply

Yes, but since Spad doesn't support Aldor's keyword extend, this cannot be done post factum...

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