Can you simplify this a bit? That's a lot of code but presumably there
is a smaller part that shows the problem. Is this it?
In [4]: simplify(Derivative(sin(x), x))
Out[4]: cos(x)
On Thu, 26 Dec 2019 at 20:05, <thomassli...@gmail.com> wrote:
>
> It looks to me like “simplify” has lost all derivatives. As you might guess
> from the code snippet, this was working earlier, but I don’t know what broke
> it, and I have made some modifications since then. I am using Python 3.7 and
> SymPy 1.5.
>
>
>
> Here is a code snippet:
>
> eq27 = Eq(eq24.lhs + I*eq25.lhs, 0)
>
> print('eq27 after creation:')
>
> print(eq27)
>
> print(latex(eq27))
>
> eq28 = Eq(eq24.lhs - I*eq25.lhs, 0)
>
> eq27 = eq27.simplify()
>
> print('eq27 after simplify 1:')
>
> print(eq27)
>
> print(latex(eq27))
>
> eq28 = eq28.simplify()
>
> eq27 = eq27.subs(Derivative(s/2 + u/2, tau, 2), Derivative(s, tau, 2)/2 +
> Derivative(u, tau, 2)/2)
>
> eq27 = eq27.subs(Derivative(I*s/2 - I*u/2, tau, 2), I*Derivative(s, tau, 2)/2
> - I*Derivative(u, tau, 2)/2)
>
> eq28 = eq28.subs(Derivative(s/2 + u/2, tau, 2), Derivative(s, tau, 2)/2 +
> Derivative(u, tau, 2)/2)
>
> eq28 = eq28.subs(Derivative(I*s/2 - I*u/2, tau, 2), I*Derivative(s, tau, 2)/2
> - I*Derivative(u, tau, 2)/2)
>
> eq27 = eq27.subs(Derivative(s/2 + u/2, tau), Derivative(s,
> tau)/2+Derivative(u, tau)/2)
>
> eq27 = eq27.subs(Derivative(I*s/2 - I*u/2, tau), I*Derivative(s,
> tau)/2-I*Derivative(u, tau)/2)
>
> eq28 = eq28.subs(Derivative(s/2 + u/2, tau), Derivative(s,
> tau)/2+Derivative(u, tau)/2)
>
> eq28 = eq28.subs(Derivative(I*s/2 - I*u/2, tau), I*Derivative(s,
> tau)/2-I*Derivative(u, tau)/2)
>
> eq27 = eq27.simplify()
>
> print('eq27 after simplify 2:')
>
> print(eq27)
>
> print(latex(eq27))
>
> eq28 = eq28.simplify()
>
> eq29 = eq26
>
> eq29 = eq29.subs(-I*(-s + u)/2, I*s/2 - I*u/2)
>
> eq29 = eq29.subs(Derivative(s/2 + u/2, tau), Derivative(s,
> tau)/2+Derivative(u, tau)/2)
>
> eq29 = eq29.subs(Derivative(I*s/2 - I*u/2, tau), I*Derivative(s,
> tau)/2-I*Derivative(u, tau)/2)
>
> eq29 = eq29.subs((I*Derivative(s, tau)/2 - I*Derivative(u, tau)/2)**2,
> -Derivative(s, tau)**2/4 + Derivative(s, tau)*Derivative(u, tau)/2 -
> Derivative(u, tau)**2/4)
>
> eq29 = eq29.subs((Derivative(s, tau)/2 + Derivative(u, tau)/2)**2,
> Derivative(s, tau)**2/4 + Derivative(s, tau)*Derivative(u, tau)/2 +
> Derivative(u, tau)**2/4)
>
> eq29 = eq29.simplify()
>
> eq29 = eq29.subs(3*s**2/8 + 3*s*u/4 + 3*u**2/8, 3*(s + u )**2/8)
>
> print('eq27:')
>
> print(eq27)
>
> print(latex(eq27))
>
> print('eq28:')
>
> print(eq28)
>
> print(latex(eq28))
>
> print('eq29:')
>
> print(eq29)
>
> print(latex(eq29))
>
>
>
> …and here is a piece of the output:
>
> eq24:
>
> Eq(\nu**2*Derivative(x, (\tau, 2)) - 2*\nu*Derivative(y, \tau) - 3*x +
> x/r**3, 0)
>
> \nu^{2} \frac{d^{2}}{d \tau^{2}} x - 2 \nu \frac{d}{d \tau} y - 3 x +
> \frac{x}{r^{3}} = 0
>
> eq25:
>
> Eq(\nu**2*Derivative(y, (\tau, 2)) + 2*\nu*Derivative(x, \tau) + y/r**3, 0)
>
> \nu^{2} \frac{d^{2}}{d \tau^{2}} y + 2 \nu \frac{d}{d \tau} x +
> \frac{y}{r^{3}} = 0
>
> eq26:
>
> Eq(-\nu**2*Derivative(x, \tau)**2/2 - \nu**2*Derivative(y, \tau)**2/2 +
> 3*x**2/2 + 1/r, C)
>
> - \frac{\nu^{2} \left(\frac{d}{d \tau} x\right)^{2}}{2} - \frac{\nu^{2}
> \left(\frac{d}{d \tau} y\right)^{2}}{2} + \frac{3 x^{2}}{2} + \frac{1}{r} = C
>
> eq24:
>
> Eq(\nu**2*Derivative(s/2 + u/2, (\tau, 2)) - 2*\nu*Derivative(I*(s - u)/2,
> \tau) - 3*s/2 - 3*u/2 + (s/2 + u/2)/(s*u)**(3/2), 0)
>
> \nu^{2} \frac{\partial^{2}}{\partial \tau^{2}} \left(\frac{s}{2} +
> \frac{u}{2}\right) - 2 \nu \frac{\partial}{\partial \tau} \frac{i \left(s -
> u\right)}{2} - \frac{3 s}{2} - \frac{3 u}{2} + \frac{\frac{s}{2} +
> \frac{u}{2}}{\left(s u\right)^{\frac{3}{2}}} = 0
>
> eq25:
>
> Eq(\nu**2*Derivative(I*(s - u)/2, (\tau, 2)) + 2*\nu*Derivative(s/2 + u/2,
> \tau) + I*(s - u)/(2*(s*u)**(3/2)), 0)
>
> \nu^{2} \frac{\partial^{2}}{\partial \tau^{2}} \frac{i \left(s - u\right)}{2}
> + 2 \nu \frac{\partial}{\partial \tau} \left(\frac{s}{2} + \frac{u}{2}\right)
> + \frac{i \left(s - u\right)}{2 \left(s u\right)^{\frac{3}{2}}} = 0
>
> eq26:
>
> Eq(-\nu**2*Derivative(I*(s - u)/2, \tau)**2/2 - \nu**2*Derivative(s/2 + u/2,
> \tau)**2/2 + 3*(s/2 + u/2)**2/2 + 1/sqrt(s*u), C)
>
> - \frac{\nu^{2} \left(\frac{\partial}{\partial \tau} \frac{i \left(s -
> u\right)}{2}\right)^{2}}{2} - \frac{\nu^{2} \left(\frac{\partial}{\partial
> \tau} \left(\frac{s}{2} + \frac{u}{2}\right)\right)^{2}}{2} + \frac{3
> \left(\frac{s}{2} + \frac{u}{2}\right)^{2}}{2} + \frac{1}{\sqrt{s u}} = C
>
> Loaded '__main__'
>
> Loaded 'runpy'
>
> eq27 after creation:
>
> Eq(\nu**2*Derivative(s/2 + u/2, (\tau, 2)) - 2*\nu*Derivative(I*(s - u)/2,
> \tau) - 3*s/2 - 3*u/2 + I*(\nu**2*Derivative(I*(s - u)/2, (\tau, 2)) +
> 2*\nu*Derivative(s/2 + u/2, \tau) + I*(s - u)/(2*(s*u)**(3/2))) + (s/2 +
> u/2)/(s*u)**(3/2), 0)
>
> \nu^{2} \frac{\partial^{2}}{\partial \tau^{2}} \left(\frac{s}{2} +
> \frac{u}{2}\right) - 2 \nu \frac{\partial}{\partial \tau} \frac{i \left(s -
> u\right)}{2} - \frac{3 s}{2} - \frac{3 u}{2} + i \left(\nu^{2}
> \frac{\partial^{2}}{\partial \tau^{2}} \frac{i \left(s - u\right)}{2} + 2 \nu
> \frac{\partial}{\partial \tau} \left(\frac{s}{2} + \frac{u}{2}\right) +
> \frac{i \left(s - u\right)}{2 \left(s u\right)^{\frac{3}{2}}}\right) +
> \frac{\frac{s}{2} + \frac{u}{2}}{\left(s u\right)^{\frac{3}{2}}} = 0
>
> eq27 after simplify 1:
>
> Eq(3*s/2 + 3*u/2 - u/(s*u)**(3/2), 0)
>
> \frac{3 s}{2} + \frac{3 u}{2} - \frac{u}{\left(s u\right)^{\frac{3}{2}}} = 0
>
> eq27 after simplify 2:
>
> Eq(3*s/2 + 3*u/2 - u/(s*u)**(3/2), 0)
>
> \frac{3 s}{2} + \frac{3 u}{2} - \frac{u}{\left(s u\right)^{\frac{3}{2}}} = 0
>
> eq27:
>
> Eq(3*s/2 + 3*u/2 - u/(s*u)**(3/2), 0)
>
> \frac{3 s}{2} + \frac{3 u}{2} - \frac{u}{\left(s u\right)^{\frac{3}{2}}} = 0
>
> eq28:
>
> Eq(3*s/2 - s/(s*u)**(3/2) + 3*u/2, 0)
>
> \frac{3 s}{2} - \frac{s}{\left(s u\right)^{\frac{3}{2}}} + \frac{3 u}{2} = 0
>
> eq29:
>
> Eq(C, (3*sqrt(s*u)*(s + u)**2 + 8)/(8*sqrt(s*u)))
>
> C = \frac{3 \sqrt{s u} \left(s + u\right)^{2} + 8}{8 \sqrt{s u}}
>
>
>
> Finally, I have pasted the LaTeX output into a Word document to make them
> more readable. (I know that Jupyter is a great tool for this, but Word is a
> quick and easy way for me to do it.) In case someone doesn’t have Word, I
> have included a pdf version.
>
>
>
> Tom
>
> (Dr. Thomas S. Ligon)
>
> thomassli...@gmail.com
>
> Frohnloher Str. 6a
> 81475 Muenchen
> Germany
> Tel. +49(89)74575075
>
>
>
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