sympy/sympy — Issue #995: mpprint doesn't properly output derivatives
Author: moorepants
Created: 2012-01-17 23:34:11+00:00
State: open

This is in regards to the physics.mechanics module.

```
In [33]: Tdelta.coeff(mG)
Out[33]: d*(d*(-wb1(t)*sin(delta(t)) + wb2(t)*cos(delta(t)))*(wb1(t)*cos(delta(t)) + wb2(t)*sin(delta(t))) + d*Derivative(wg3(t), t)) - d*(-ds1*wb2(t)**2 + ds3*Derivative(wb2(t), t) - (ds1*wb3(t) - ds3*wb1(t))*wb3(t) + av1(t))*sin(delta(t)) + d*(ds1*wb1(t)*wb2(t) + ds1*Derivative(wb3(t), t) + ds3*wb2(t)*wb3(t) - ds3*Derivative(wb1(t), t) + av2(t))*cos(delta(t))

In [34]: me.mpprint(Tdelta.coeff(mG))
⎛ 2
d⋅(d⋅(-wb₁⋅sin(δ) + wb₂⋅cos(δ))⋅(wb₁⋅cos(δ) + wb₂⋅sin(δ)) + d⋅wg₃) - d⋅⎝- ds₁⋅wb₂ (t) + ds₃⋅wb₂ - (ds₁⋅wb₃ - ds₃⋅wb₁)⋅

⎞
wb₃ + av₁⎠⋅sin(δ) + d⋅(ds₁⋅wb₁⋅wb₂ + ds₁⋅wb₃ + ds₃⋅wb₂⋅wb₃ - ds₃⋅wb₁ + av₂)⋅cos(δ)
```

Notice that the Derivative terms are not distinguished in the mpprint output. The should have a dot over top or set as dx/dt.