Aaron, Thanks a lot! I appreciate the response. I'm set up with git now, and solve is up and running.
Matthew, I'd definitely be interested in swapping notes. My code isn't posted anywhere right now, just started work on this project about a week ago. I'll send you an e-mail and explain what I'm working on. Based on what I looked at in the stats module, I think there will be a good amount of overlap. Glad there's someone else interested in random variables for SymPy! -- Matt Robinson On Mar 22, 10:03 pm, Matthew Rocklin <[email protected]> wrote: > Hi Matthew, > > I think the idea of adding random variables to SymPy is an excellent one. > So excellent that I worked last year :) > > Solve is definitely the way to go with your current problem. Check out > sympy.stats.crv.py line 255. > > If you're interested in swapping notes let me know. If you're interested in > what's going on with the current sympy implementation of random variables > check out the Statistics label in the code > trackerhttp://code.google.com/p/sympy/issues/list?can=2&q=label%3AStatistics > or shoot me an e-mail. > > If your code is posted somewhere let me/us know. I'd be very interested to > see what your approach to this problem was. > > -Matthew > > > > On Thu, Mar 22, 2012 at 6:45 PM, Aaron Meurer <[email protected]> wrote: > > This works in the git master: > > > In [166]: solve((1-exp(-4*x))-y,x) > > Out[166]: > > ⎡ ⎛ _______⎞ ⎛ _______⎞ ⎛ _______⎞ ⎛ > > _______⎞⎤ > > ⎢ ⎜ ╱ -1 ⎟ ⎜ ╱ -1 ⎟ ⎜ ╱ -1 ⎟ ⎜ ╱ -1 > > ⎟⎥ > > ⎢log⎜-4 ╱ ───── ⎟, log⎜4 ╱ ───── ⎟, log⎜-ⅈ⋅4 ╱ ───── ⎟, log⎜ⅈ⋅4 ╱ > > ───── ⎟⎥ > > ⎣ ⎝ ╲╱ y - 1 ⎠ ⎝╲╱ y - 1 ⎠ ⎝ ╲╱ y - 1 ⎠ ⎝ ╲╱ y - > > 1 ⎠⎦ > > > In [167]: solve((1-exp(4*x))-y,x) > > Out[167]: > > ⎡ ⎛ 4 ________⎞ ⎛ 4 ________⎞ ⎛ 4 ________⎞ ⎛4 ________⎞⎤ > > ⎣log⎝-ⅈ⋅╲╱ -y + 1 ⎠, log⎝ⅈ⋅╲╱ -y + 1 ⎠, log⎝-╲╱ -y + 1 ⎠, log⎝╲╱ -y + 1 ⎠⎦ > > > guess_solve_strategy was removed since 0.7.1, and solving procedures > > in general have been improved. > > > By the way, since you are implementing a random variable class, you > > might check out the new stats module that is also in the git master. > > > Seehttps://github.com/sympy/sympy/wiki/Getting-the-bleeding-edgefor > > a little guide on how to get the git master. > > > Aaron Meurer > > > On Thu, Mar 22, 2012 at 7:14 PM, Matthew Robinson > > <[email protected]> wrote: > > > Hi Everyone, > > > > First of all, just wanted to say that I just recently started working > > > in sympy. I've enjoyed it so far and think that it is a wonderful > > > project. > > > > On to my issue. I'm currently in the process of writing a random > > > variable class, and need to write a procedure that can invert > > > cumulative distribution functions. Basically, it seems like the solve > > > procedure chokes when there is a negative symbol in an exponential > > > function. The procedure works fine if there is a non-negative symbol > > > instead. For instance, solve((1-exp(-4*x))-y,x) fails, whereas > > > something like solve((1-exp(4*x))-y,x) works correctly. The negative > > > sign does not look like it's the problem, since solve works with > > > negative integers and floating point numbers in the exponential. > > > > The exception raised is NotImplementedError, and may be related to the > > > guess_solve_strategy procedure. > > > > Note that I haven't looked through the code for the solve procedure > > > yet. Wanted to see if anyone else has run into this issue. > > > > -- Matt Robinson > > > > -- > > > You received this message because you are subscribed to the Google > > Groups "sympy" group. > > > To post to this group, send email to [email protected]. > > > To unsubscribe from this group, send email to > > [email protected]. > > > For more options, visit this group at > >http://groups.google.com/group/sympy?hl=en. > > > -- > > You received this message because you are subscribed to the Google Groups > > "sympy" group. > > To post to this group, send email to [email protected]. > > To unsubscribe from this group, send email to > > [email protected]. > > For more options, visit this group at > >http://groups.google.com/group/sympy?hl=en.- Hide quoted text - > > - Show quoted text - -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
