Hi, I'm not completely clear on what you are doing, as I don't use jython, but couldn't you just use str(), as in
>>> a = str(diff(2*exp(-x*x/50)+sin(pi*x)/x, x)) >>> type(a) <type 'str'> >>> F1D(a) # probably works now Also, you can use sympify() or just S() to convert from a string to a SymPy expression: >>> func = func="2*exp(-x*x/50)+sin(pi*x)/x" >>> print S(diff(func,x)) -sin(pi*x)/x**2 + pi*cos(pi*x)/x - 2*x*exp(-x**2/50)/25 On Jul 5, 2009, at 7:35 AM, sergei175 wrote: > > > Hi, > > Sympy seems is rather advanced and useful project. > > I've tried to test it using jhepwork, and even included it into > http://jwork.org/jhepwork/download/ > (version 2.0) for test purpose (directory python/packages) > > Apparently, one can run sympy using Jython (v2.5) and Java ! > A code snipped is below. Load it into the jHepWork IDE > editor and press the button [run]. > > However, there is on feature I want to understand. To plot a function > as in the example below using F1D class, I need to pass a string > representing this function. However, simpy cannot accept strings for > the > statements such as diff() or integral(). In the below example, what I > want > to do is to type "diff(func,x)". > > Further, if I want to plot the result of "diff" or integration, I > need again a string > representing the output function and pass it to the F1D class as in > the example. > How can I do this? > > thanks, Sergei > > ******************************************************** > # jHepWork Jython example > > from java.awt import Font,Color > from jhplot import * > > c1 = HPlot("Canvas") > c1.setAutoRange() > > c1.setGTitle("Example", Color.red) > c1.setNameX("X") > c1.setNameY("Y") > c1.setName("Simpy example") > c1.visible() > c1.setAutoRange() > > # draw function > func="2*exp(-x*x/50)+sin(pi*x)/x" > f1 = F1D(func, -2.0, 5.0) > c1.draw(f1) > > # use sympy > from sympy import * > x = Symbol('x') > print diff(2*exp(-x*x/50)+sin(pi*x)/x, x) > > # how to get string with the result > # to build F1D with results for drawing? > > # export to some image (png,eps,pdf,jpeg...) > # c1.export(Editor.DocMasterName()+".png") > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to sympy@googlegroups.com To unsubscribe from this group, send email to sympy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sympy?hl=en -~----------~----~----~----~------~----~------~--~---
