python 2.7 - SymPy: simplifying of inverse function -

-

i define 2 sympy functions f, g, s.t. g inverse of f:

import sympy sy  g = sy.function('g')  class f(sy.function):     def inverse(self, argindex=1):         return g  x, y = sy.symbols('x y') print sy.solve(y - f(x), x) # [g(y)] - correct

but if try evaluate f(g(x)) sympy doesnt simplify this:

print f(g(x))               # f(g(x)) print f(g(x)).doit()        # f(g(x)) - why not x? print f(g(x)).simplify()    # f(g(x)) - why not x?

question: how sympy f(g(x)) x?

inverse isn't implemented that. opened https://github.com/sympy/sympy/issues/10487 it. ideally write below should work default.

you can make work defining _eval_simplify, like

class f(sy.function):     def inverse(self, argindex=1):         return g      def _eval_simplify(self, ratio, measure):         if isinstance(self.args[0], self.inverse()):             return self.args[0].args[0]         return self

if have many classes want can put in superclass.

in [30]: f(g(x)) out[30]: f(g(x))  in [31]: f(g(x)).simplify() out[31]: x

or if prefer doit() can define doit().


Comments

Post a Comment

Popular posts from this blog

Hatching array of circles in AutoCAD using c# -

-
i beginner in autocad plugins .i have created array of circle using following code. now, have hatch circles in array .how that??how hatch circles @ once? moreover, how can return hatch method , use hatch objects.sorry language.thanks in advance. [assembly: commandclass(typeof(beamsection.class1))] namespace beamsection { public class class1 { //class1 obj = new class1(); [commandmethod("beamatsupport")] public void addlightweightpolyline() { // current document , database document acdoc = application.documentmanager.mdiactivedocument; database accurdb = acdoc.database; promptpointresult ppr = acdoc.editor.getpoint("\nselect starting point "); var ucs = acdoc.editor.currentusercoordinatesystem; point3d startingpt = ppr.value.transformby(ucs); list<double> radius = new list<double>(); radius.add(0.5);
Read more

ios - UITEXTFIELD InputView Uipicker not working in swift -

-
hello trying pop uipickerview view programmatically when user clicks on textfield. have tried doesn't doing anything. isn't working. nothing happening when click textfield class userprofiletableviewcontroller: uitableviewcontroller,uitextfielddelegate,uipickerviewdelegate,uipickerviewdatasource { var itempicker: uipickerview! = uipickerview() @iboutlet weak var gendertxtfield: uitextfield! var gender = ["male","female"] override func viewdidload() { super.viewdidload() gendertxtfield.delegate = self itempicker!.delegate = self itempicker!.datasource = self itempicker!.backgroundcolor = uicolor.blackcolor() self.gendertxtfield.inputview = itempicker } func numberofcomponentsinpickerview(pickerview: uipickerview) -> int{ return 1 } // returns # of rows in each component.. func pickerview(pickerview: uipickerview, numberofrowsincomponent component:
Read more