For graphing strain load on a shaft in relation to coordinate x, I have
created a set of piecewise functions. Now I wanted to munge them into a
single parametrized vector to easily get the length via norm() at a
specified point.
M_Tx = piecewise([[[0, l1], M_t], [(l1, l1+l2), 0]])
M_by = piecewise([[[0, l1], -A_z * x], [(l1, l1+l2), -B_z * (l1+l2-x)]])
M_bz = piecewise([[[0, l1], A_y * x], [(l1, l1+l2), B_y * (l1+l2-x)]])
N_x = piecewise([[[0, l1], -A_x], [(l1, l1+l2), 0]])
Q_y = piecewise([[[0, l1], -A_y], [(l1, l1+l2), B_y]])
Q_z = piecewise([[[0, l1], -A_z], [(l1, l1+l2), B_z]])
M_vec(x) = vector([M_Tx, M_by, M_bz]).column()
show(r"$\vec M=\left(\begin{array}{c} M_{Tx} \\ M_{by} \\ M_{bz}
\end{array}\right)=$", M_vec(x = l1).n(digits=4), "kN $=$", round(M_vec(x =
l1).norm(), 4), "kN")
But, this does not work.
Error in lines 27-27
Traceback (most recent call last):
File "/cocalc/lib/python2.7/site-packages/smc_sagews/sage_server.py",
line 996, in execute
exec compile(block+'\n', '', 'single') in namespace, locals
File "", line 1, in <module>
File "sage/structure/element.pyx", line 838, in sage.structure.element.
Element.n (/ext/sage/sage-8.0/src/build/cythonized/sage/structure/element.c:
7961)
return self.numerical_approx(prec, digits, algorithm)
File "sage/symbolic/expression.pyx", line 5718, in sage.symbolic.
expression.Expression.numerical_approx (/ext/sage/sage-8.0/src/build/
cythonized/sage/symbolic/expression.cpp:35056)
x = x._convert(kwds)
File "sage/symbolic/expression.pyx", line 1261, in sage.symbolic.
expression.Expression._convert (/ext/sage/sage-8.0/src/build/cythonized/sage
/symbolic/expression.cpp:10465)
cdef GEx res = self._gobj.evalf(0, kwds)
File "sage/libs/pynac/pynac.pyx", line 1343, in
sage.libs.pynac.pynac.py_float
(/ext/sage/sage-8.0/src/build/cythonized/sage/libs/pynac/pynac.cpp:15280)
return p.complex_field()(n)
File "sage/structure/category_object.pyx", line 823, in sage.structure.
category_object.CategoryObject.__getattr__ (/ext/sage/sage-8.0/src/build/
cythonized/sage/structure/category_object.c:7662)
return self.getattr_from_category(name)
File "sage/structure/category_object.pyx", line 838, in sage.structure.
category_object.CategoryObject.getattr_from_category (/ext/sage/sage-8.0/src
/build/cythonized/sage/structure/category_object.c:7826)
attr = getattr_from_other_class(self, cls, name)
File "sage/structure/misc.pyx", line 294, in
sage.structure.misc.getattr_from_other_class
(/ext/sage/sage-8.0/src/build/cythonized/sage/structure/misc.c:1866)
raise dummy_attribute_error
AttributeError: 'ComplexField_class_with_category' object has no attribute
'complex_field'
Is it that piecewise functions are not yet fully fledged out, or is my lack
of sage routine that is to blame?
Any hints most welcome : )
#Best Regards/Marcel
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