def vpprint(expr, **settings):
r"""Function for pretty printing of expressions generated in the
sympy.physics vector package.
Mainly used for expressions not inside a vector; the output of running
scripts and generating equations of motion. Takes the same options as
SymPy's pretty_print(); see that function for more information.
Parameters
==========
expr : valid sympy object
SymPy expression to pretty print
settings : args
Same as pretty print
Examples
========
Use in the same way as pprint
"""
mp = VectorPrettyPrinter(settings)
print(mp.doprint(expr))
def test_vector_pretty_print():
# TODO : The unit vectors should print with subscripts but they just
# print as `n_x` instead of making `x` a subscritp with unicode.
pp = VectorPrettyPrinter()
expected = (u' 2\na *\x1b[94m\x1b[1mn_x\x1b[0;0m\x1b[0;0m + '
u'b*\x1b[94m\x1b[1mn_y\x1b[0;0m\x1b[0;0m + '
u'c\u22c5sin(\u03b1)*\x1b[94m\x1b[1mn_z\x1b[0;0m\x1b[0;0m')
assert expected == pp.doprint(v)
assert expected == v._pretty().render()
expected = (u'\u03b1*\x1b[94m\x1b[1mn_x\x1b[0;0m\x1b[0;0m + '
u'sin(\u03c9)*\x1b[94m\x1b[1mn_y\x1b[0;0m\x1b[0;0m + '
u'\u03b1\u22c5\u03b2*\x1b[94m\x1b[1mn_z\x1b[0;0m\x1b[0;0m')
assert expected == pp.doprint(w)
assert expected == w._pretty().render()
def render(self, *args, **kwargs):
self = e
ar = self.args # just to shorten things
mpp = VectorPrettyPrinter()
if len(ar) == 0:
return unicode(0)
ol = [] # output list, to be concatenated to a string
for i, v in enumerate(ar):
# if the coef of the dyadic is 1, we skip the 1
if ar[i][0] == 1:
ol.append(u(" + ") +
mpp.doprint(ar[i][1]) +
u("\u2a02 ") +
mpp.doprint(ar[i][2]))
# if the coef of the dyadic is -1, we skip the 1
elif ar[i][0] == -1:
ol.append(u(" - ") +
mpp.doprint(ar[i][1]) +
u("\u2a02 ") +
mpp.doprint(ar[i][2]))
# If the coefficient of the dyadic is not 1 or -1,
# we might wrap it in parentheses, for readability.
elif ar[i][0] != 0:
arg_str = mpp.doprint(ar[i][0])
if isinstance(ar[i][0], Add):
arg_str = u("(%s)") % arg_str
if arg_str.startswith(u("-")):
arg_str = arg_str[1:]
str_start = u(" - ")
else:
str_start = u(" + ")
ol.append(str_start + arg_str + u(" ") +
mpp.doprint(ar[i][1]) +
u("\u2a02 ") +
mpp.doprint(ar[i][2]))
outstr = u("").join(ol)
if outstr.startswith(u(" + ")):
outstr = outstr[3:]
elif outstr.startswith(" "):
outstr = outstr[1:]
return outstr