A good start would be the simplification section of the tutorial http://docs.sympy.org/latest/tutorial/index.html.
In this case, collect(expr1, [x11, x12, x13]) does what you want. factor() only does complete factorizations (into products of terms). This is explained in more depth in the tutorial. Aaron Meurer On Tue, Nov 3, 2015 at 2:47 PM, Hugh <[email protected]> wrote: > import sympy > sympy.init_session() > > > x11, x12, x13, x21, x22, x23, x31, x32, x33 = symbols('x_1:4(1:4)') > > A = Matrix(3,3,symbols('x_1:4(1:4)')) > expr1 = A.det() > > expr2 = x11*(x22*x33 - x23*x32) - x12*(x21*x33 -x23*x31) + x13*(x21*x32 - > x22*x31) > > # How to get expr2 from expr1? > > I would like to use sympy to rewrite expressions just like how people would > commonly do when writing proofs or doing homework. What are the > documentation that I must read so that I can be proficient at this? > > I've read the tutorial and some of the modules in the module reference but > feel that I have just barely touched the surface of sympy's capabilities. > For example, in the above code snippet, I don't know how to manipulate expr1 > to get expr2. I thought expr1.factor() would work but it didn't. > > Please advise. > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/sympy. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/9cbb1995-3987-44f1-8c72-6de11e6a4013%40googlegroups.com. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6%2BPwK2EWr3_vt_9cNSv7afDyzWrZ-5hEF_cR05qFZ4S6g%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
