Thanks! That's a big help, but I am not finished yet. Here is where I am now:
Step 1: Use your code. name 'StrPrinter' is not defined changed StrPrinter to sympy.printing.str.StrPrinter https://docs.sympy.org/latest/modules/printing.html name 'degree' is not defined I tried key=sympy.printing.str.degree, but that gave me module 'sympy.printing.str' has no attribute 'degree' Then I tried key=sympy.degree and that worked. Now the two series are being printed in the desired order. Step 2: Use latex I tried changing print(doprint(series)) to print(latex(doprint(series))) and the result is \mathtt{\text{-2.565*t + 147.94*t**3 - 2867.7*t**5}} which doesn't format correctly in Word's equation editor or in www.overleaf.com, where it formats correctly, but issues an error Undefined control sequence. LaTeX Error: \mathtt allowed only in math mode. I tried changing the string to -2.565*t + 147.94*t**3 - 2867.7*t**5 and this formats correctly in Word and in Overleaf. Then I tried doprint = sympy.printing.latex.LatexPrinter(settings={'order':'none'}).doprint but that throws an exception '_PrintFunction' object has no attribute 'LatexPrinter' even though the class class sympy.printing.latex.LatexPrinter(settings=None) is defined in https://docs.sympy.org/latest/modules/printing.html#module-sympy.printing.latex Still to do: Learn how this works. Learn why evalf(5) works. The documentation at https://docs.sympy.org/latest/modules/evalf.html doesn't make it clear to me what the possible arguments are and what they mean. Find documentation for sorted and key=degree. I searched for sympy degree and found polynomials and angles, but still don't understand this one. On Sunday, March 5, 2023 at 8:53:32 PM UTC+1 Oscar wrote: On Sun, 5 Mar 2023 at 08:32, Thomas Ligon <[email protected]> wrote: > > I have a lot of power series that look like this (but going up to t**12): > exp1 = -2867.70035529489*t**5 + 147.938724526848*t**3 - 2.56500070531002*t > While trying to gain some insight into the mathematics that creates them, I want to print a shorter version, such as > - 2.565 t + 147.93872 t**3- 2867.70036 t**5 > but the best I have achieved is > - 2867.70036 t^{5} + \left(147.93872 t^{3} - 2.565 t\right) > Rounding the numbers was easy, but I would prefer to round to 5 digits total, not 5 digits after the decimal point. I was able to convert the expression to a list and sort the list, but when I converted the list back to an expression, I didn't succeed in producing the order I wanted. You can get 5 digits by using exp1.evalf(5). It is surprisingly difficult to control the order of terms in sympy's printing functionality but it is possible: In [1]: exp1 = -2867.70035529489*t**5 + 147.938724526848*t**3 - 2.56500070531002*t In [2]: doprint = StrPrinter(settings={'order':'none'}).doprint In [3]: series = Add(*sorted(exp1.evalf(5).args, key=degree), evaluate=False) In [4]: print(doprint(series)) -2.565*t + 147.94*t**3 - 2867.7*t**5 There are two steps to controlling the order: - Ordering the terms in the expression itself (the series variable above). - Getting the printer to respect that ordering ('order':'none'). It should be possible to set order=None with init_printing and that does work for the pretty printer but not for string printing (i.e. print(expr) or str(expr)). -- Oscar -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/sympy/d48be44a-e979-41fd-aa37-1fabadde9b7an%40googlegroups.com.
