Re: [sympy] Overriding printing library to put prefix on symbols for code generation

As easy as that! Thank you, that's essentially exactly what I wanted to do. cheers Richard On Thursday, 5 November 2015 02:21:46 UTC+13, Jason Moore wrote: > > This should be: > > class MyPrinter(CCodePrinter): > def _print_Symbol(self, expr): > name = super(MyPrinter,

Re: [sympy] Powers and complex numbers

Thank you. On Wednesday, November 4, 2015 at 9:25:17 PM UTC+2, Aaron Meurer wrote: > > You can generally do this sort of thing using replace(). > Unfortunately, the pattern matcher doesn't recognize rational numbers > as a/b, so you have to do a more manual check. This should work: > >

[sympy] Writing Test cases in SymPy

Hi everyone There have been cases with me while solving bugs in SmyPy in certain cases that i feel the need to follow certain rules for writing cases. I think that there are no hard and fast rules to write test cases for everything in genral for `new implementation`(for any software). For

Re: [sympy] Powers and complex numbers

So, there is no way to do it using subs and/or some manipulations? real_root(-1, 3) is of no help, because I can have arbitrary expression. On Wednesday, November 4, 2015 at 6:29:29 PM UTC+2, Aaron Meurer wrote: > > You need to use real_root, like > > In [3]: real_root(-1, 3) > Out[3]: -1 > >

Re: [sympy] Powers and complex numbers

You can generally do this sort of thing using replace(). Unfortunately, the pattern matcher doesn't recognize rational numbers as a/b, so you have to do a more manual check. This should work: e.replace(lambda i: i.is_Pow and i.base == x and i.exp.is_Rational, lambda i: real_root(-1,

Re: [sympy] Powers and complex numbers

You need to use real_root, like In [3]: real_root(-1, 3) Out[3]: -1 In [4]: real_root(-1, 3)**2 Out[4]: 1 SymPy, like most math libraries, uses complex roots (i.e., principal roots) because they have nicer mathematical properties. Aaron Meurer On Wed, Nov 4, 2015 at 3:30 AM, Paul Royik

Re: [sympy] What to read to be good at rewriting expressions?

Yes, for now, Mul automatically distributes constants, so you have to use evaluate=False to factor out something like -1. Aaron Meurer On Wed, Nov 4, 2015 at 5:13 AM, Hugh <7141...@gmail.com> wrote: > Thanks Aaron for pointing out the simplification section of the tutorial. > > Actually,

Re: [sympy] What to read to be good at rewriting expressions?

Okay. Thanks again for your help. On Thursday, 5 November 2015 00:36:46 UTC+8, Aaron Meurer wrote: > > Yes, for now, Mul automatically distributes constants, so you have to > use evaluate=False to factor out something like -1. > > Aaron Meurer > > On Wed, Nov 4, 2015 at 5:13 AM, Hugh

[sympy] Powers and complex numbers

I have the following expresssion: f=x**(Rational(2,3)) How can I get 1, when substituting (-1) instead of complex number? For now, I got complex number when run f.subs(x,-1).evalf() -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from

Re: [sympy] What to read to be good at rewriting expressions?

Thanks Aaron for pointing out the simplification section of the tutorial. Actually, collect(expr1, [x11, x12, x13]) does almost what I wanted. I still need to factor a -1 from x12( -x21x33 + x23x31). How would you do it using replace() like what I did? I also tried putting (x12*a).factor() as

Re: [sympy] What to read to be good at rewriting expressions?

Thanks Mateusz for sharing the code. I thought it was a clever solution to solve my problem. On Wednesday, 4 November 2015 07:35:45 UTC+8, Mateusz Paprocki wrote: > > Hi, > > On 3 November 2015 at 21:47, Hugh <714...@gmail.com > wrote: > > import sympy > > sympy.init_session() > > > > > >