[sympy] Re: Confusion with generic functions and derivatives

2008-06-07 Thread Ondrej Certik
On Sat, Jun 7, 2008 at 11:34 AM, Ondrej Certik [EMAIL PROTECTED] wrote: On Fri, Jun 6, 2008 at 7:50 PM, Rickard Armiento [EMAIL PROTECTED] wrote: Hi, I recently discovered sympy and really like the idea of a symbolic math engine in python. I'm trying to learn how to use it, but I am

[sympy] Re: Confusion with generic functions and derivatives

2008-06-07 Thread Ondrej Certik
On Fri, Jun 6, 2008 at 7:50 PM, Rickard Armiento [EMAIL PROTECTED] wrote: Hi, I recently discovered sympy and really like the idea of a symbolic math engine in python. I'm trying to learn how to use it, but I am confusing myself with how to work with generic functions. Any help is much

[sympy] Re: sympify and matrices

2008-06-07 Thread Ondrej Certik
So that's not how I would like this to be. It should either work for all functions or for no functions. I see. I do not use numpy matrices anyway, just arrays, as they are not really the linear algebra matrices, only arrays with some peculiar modifications - they have no extra value that

[sympy] Re: sympify and matrices

2008-06-07 Thread Ondrej Certik
Let's clean this up. I sent an email to the numpy-list asking for an advice: http://projects.scipy.org/pipermail/numpy-discussion/2008-June/034801.html The ultimate reason that Matrix is not a subclass of a Basic is that it is mutable, while SymPy objects need to be immutable, so that when you

[sympy] Re: sympify and matrices

2008-06-07 Thread Ondrej Certik
Disadvantage -- if one needs to set entries of a Matrix using the syntax A[1, 2] = y not only at the beginning of the calculaton, but also in the middle, then he would have to do: A = Matrix(Array(A)[1,2] = y). Of course A[1,2] = y would create an exception saying: use the A =

[sympy] Questions about expression forms

2008-06-07 Thread Mark Dewing
Several expression forms seem be reduced to a canonical form (both in the representation and in the pretty printed output). Examples: 1. Factorial vs. Gamma function 2. Sqrt(radical) vs. a**(1/2) Is there any way to control what form is used? Another case, (i*j)**(1/2) is represented as