galgebra/mv.py
"""
Multivector and Linear Multivector Differential Operator
"""
import copy
import numbers
import operator
from functools import reduce
from typing import List, Any, Tuple, Union, TYPE_CHECKING
from sympy import (
Symbol, Function, S, expand, Add,
sin, cos, sinh, cosh, sqrt, trigsimp,
simplify, diff, Expr, Abs, collect, SympifyError,
)
from sympy import exp as sympy_exp
from sympy import N as Nsympy
from sympy.printing.latex import LatexPrinter as _LatexPrinter
from sympy.printing.str import StrPrinter as _StrPrinter
from . import printer
from . import metric
from .printer import ZERO_STR
from ._utils import KwargParser as _KwargParser
from . import dop
if TYPE_CHECKING:
from galgebra.ga import Ga
# This file does not and should not use these.
# Unfortunately, some of our examples do.
ONE = S.One
ZERO = S.Zero
HALF = S.Half
# Add custom settings to the builtin latex printer
_LatexPrinter._default_settings.update({
'galgebra_mv_fmt': 1
})
_StrPrinter._default_settings.update({
'galgebra_mv_fmt': 1
})
########################### Multivector Class ##########################
class Mv(printer.GaPrintable):
"""
Wrapper class for multivector objects (``self.obj``) so that it is easy
to overload operators (``*``, ``^``, ``|``, ``<``, ``>``) for the various
multivector products and for printing.
Also provides a constructor to easily instantiate multivector objects.
Additionally, the functionality
of the multivector derivative have been added via the special vector
``grad`` so that one can take the geometric derivative of a multivector
function ``A`` by applying ``grad`` from the left, ``grad*A``, or the
right ``A*grad`` for both the left and right derivatives. The operator
between the ``grad`` and the 'A' can be any of the multivector product
operators.
If ``f`` is a scalar function ``grad*f`` is the usual gradient of a function.
If ``A`` is a vector function ``grad|f`` is the divergence of ``A`` and
``-I*(grad^A)`` is the curl of ``A`` (I is the pseudo scalar for the geometric
algebra)
Attributes
----------
obj : sympy.core.Expr
The underlying sympy expression for this multivector
"""
################### Multivector initialization #####################
# This is read by one code path in `galgebra.printer.Fmt`. Only one example
# sets it.
fmt = 1
dual_mode_lst = ['+I', 'I+', '+Iinv', 'Iinv+', '-I', 'I-', '-Iinv', 'Iinv-']
@staticmethod
def setup(ga: 'Ga') -> Tuple['Mv', List['Mv'], 'Mv']:
"""
Set up constant multivectors required for multivector class for
a given geometric algebra, `ga`.
"""
# copy basis in case the caller wanted to change it
return ga.mv_I, list(ga.mv_basis), ga.mv_x
@staticmethod
def Mul(A: 'Mv', B: 'Mv', op: str) -> 'Mv':
"""
Function for all types of geometric multiplications called by
overloaded operators for ``*``, ``^``, ``|``, ``<``, and ``>``.
"""
if not isinstance(A, Mv):
A = B.Ga.mv(A)
if not isinstance(B, Mv):
B = A.Ga.mv(B)
if op == '*':
return A * B
elif op == '^':
return A ^ B
elif op == '|':
return A | B
elif op == '<':
return A < B
elif op == '>':
return A > B
else:
raise ValueError('Operation ' + op + 'not allowed in Mv.Mul!')
def characterise_Mv(self) -> None:
if self.char_Mv:
return
obj = expand(self.obj)
if isinstance(obj, numbers.Number):
self.i_grade = 0
self.is_blade_rep = True
self.grades = [0]
return
if obj.is_commutative:
self.i_grade = 0
self.is_blade_rep = True
self.grades = [0]
return
if isinstance(obj, Add):
args = obj.args
else:
if obj in self.Ga.blades.flat:
self.is_blade_rep = True
self.i_grade = self.Ga.blades_to_grades_dict[obj]
self.grades = [self.i_grade]
self.char_Mv = True
self.blade_flg = True
return
else:
args = [obj]
grades = []
# print 'args =', args
self.is_blade_rep = True
for term in args:
if term.is_commutative:
if 0 not in grades:
grades.append(0)
else:
c, nc = term.args_cnc(split_1=False)
blade = nc[0]
# print 'blade =', blade
if blade in self.Ga.blades.flat:
grade = self.Ga.blades_to_grades_dict[blade]
if grade not in grades:
grades.append(grade)
else:
self.char_Mv = True
self.is_blade_rep = False
self.i_grade = None
return
if len(grades) == 1:
self.i_grade = grades[0]
else:
self.i_grade = None
self.grades = grades
self.char_Mv = True
# helper methods called by __init__. Note that these names must not change,
# as the part of the name after `_make_` is public API via the string
# argument passed to __init__.
#
# The double underscores in argument names are to force the passing
# positionally. When python 3.8 is the lowest supported version, we can
# switch to using the / syntax from PEP570
@staticmethod
def _make_grade(ga: 'Ga', __name_or_coeffs: Union[str, list, tuple], __grade: int, **kwargs) -> Expr:
""" Make a pure grade multivector. """
def add_superscript(root, s):
if not s:
return root
return '{}__{}'.format(root, s)
grade = __grade
kw = _KwargParser('_make_grade', kwargs)
if isinstance(__name_or_coeffs, str):
name = __name_or_coeffs
f = kw.pop('f', False)
kw.reject_remaining()
if isinstance(f, bool):
if f: # Is a multivector function of all coordinates
return sum([Function(add_superscript(name, super_script), real=True)(*ga.coords) * base
for super_script, base in zip(ga.blade_super_scripts[grade], ga.blades[grade])])
else: # Is a constant multivector function
return sum([Symbol(add_superscript(name, super_script), real=True) * base
for super_script, base in zip(ga.blade_super_scripts[grade], ga.blades[grade])])
else: # Is a multivector function of tuple f variables
return sum([Function(add_superscript(name, super_script), real=True)(*f) * base
for super_script, base in zip(ga.blade_super_scripts[grade], ga.blades[grade])])
elif isinstance(__name_or_coeffs, (list, tuple)):
coeffs = __name_or_coeffs
kw.reject_remaining()
if len(coeffs) <= len(ga.blades[grade]):
return sum([
coef * base
for coef, base in zip(coeffs, ga.blades[grade][:len(coeffs)])])
else:
raise ValueError("Too many coefficients")
else:
raise TypeError("Expected a string, list, or tuple")
@staticmethod
def _make_scalar(ga: 'Ga', __name_or_value: Union[str, Expr], **kwargs) -> Expr:
""" Make a scalar multivector """
if isinstance(__name_or_value, str):
name = __name_or_value
return Mv._make_grade(ga, name, 0, **kwargs)
else:
value = __name_or_value
return value
@staticmethod
def _make_vector(ga: 'Ga', __name_or_coeffs: Union[str, list, tuple], **kwargs) -> Expr:
""" Make a vector multivector """
return Mv._make_grade(ga, __name_or_coeffs, 1, **kwargs)
@staticmethod
def _make_bivector(ga: 'Ga', __name_or_coeffs: Union[str, list, tuple], **kwargs) -> Expr:
""" Make a bivector multivector """
return Mv._make_grade(ga, __name_or_coeffs, 2, **kwargs)
@staticmethod
def _make_pseudo(ga: 'Ga', __name_or_coeffs: Union[str, list, tuple], **kwargs) -> Expr:
""" Make a pseudo scalar multivector """
return Mv._make_grade(ga, __name_or_coeffs, ga.n, **kwargs)
@staticmethod
def _make_mv(ga: 'Ga', __name: str, **kwargs) -> Expr:
""" Make a general (2**n components) multivector """
if not isinstance(__name, str):
raise TypeError("Must be a string")
return reduce(operator.add, (
Mv._make_grade(ga, __name, grade, **kwargs)
for grade in range(ga.n + 1)
))
@staticmethod
def _make_spinor(ga: 'Ga', __name: str, **kwargs) -> Expr:
""" Make a general even (spinor) multivector """
if not isinstance(__name, str):
raise TypeError("Must be a string")
return reduce(operator.add, (
Mv._make_grade(ga, __name, grade, **kwargs)
for grade in range(0, ga.n + 1, 2)
))
@staticmethod
def _make_odd(ga: 'Ga', __name: str, **kwargs) -> Expr:
""" Make a general odd multivector """
if not isinstance(__name, str):
raise TypeError("Must be a string")
return reduce(operator.add, (
Mv._make_grade(ga, __name, grade, **kwargs)
for grade in range(1, ga.n + 1, 2)
), S.Zero) # base case needed in case n == 0
# aliases
_make_grade2 = _make_bivector
_make_even = _make_spinor
def __init__(self, *args, ga, recp=None, coords=None, **kwargs):
"""
__init__(self, *args, ga, recp=None, **kwargs)
Note this constructor is overloaded, based on the type and number of
positional arguments:
.. class:: Mv(*, ga, recp=None)
:noindex:
Create a zero multivector
.. class:: Mv(expr, /, *, ga, recp=None)
:noindex:
Create a multivector from an existing vector or sympy expression
.. class:: Mv(coeffs, grade, /, ga, recp=None)
:noindex:
Create a multivector constant with a given grade
.. class:: Mv(name, category, /, *cat_args, ga, recp=None, f=False)
:noindex:
Create a multivector constant with a given category
.. class:: Mv(name, grade, /, ga, recp=None, f=False)
:noindex:
Create a multivector variable or function of a given grade
.. class:: Mv(coeffs, category, /, *cat_args, ga, recp=None)
:noindex:
Create a multivector variable or function of a given category
``*`` and ``/`` in the signatures above are python
3.8 syntax, and respectively indicate the boundaries between
positional-only, normal, and keyword-only arguments.
Parameters
----------
ga : ~galgebra.ga.Ga
Geometric algebra to be used with multivectors
recp : object, optional
Normalization for reciprocal vector. Unused.
name : str
Name of this multivector, if it is a variable or function
coeffs : sequence
Sequence of coefficients for the given category.
This is only meaningful
category : str
One of:
* ``"grade"`` - this takes an additional argument, the grade to
create, in ``cat_args``
* ``"scalar"``
* ``"vector"``
* ``"bivector"`` / ``"grade2"``
* ``"pseudo"``
* ``"mv"``
* ``"even"`` / ``"spinor"``
* ``"odd"``
f : bool, tuple
True if function of coordinates, or a tuple of those coordinates.
Only valid if a name is passed
coords :
This argument is always accepted but ignored.
It is incorrectly described internally as the coordinates to be
used with multivector functions.
"""
kw = _KwargParser('__init__', kwargs)
self.Ga = ga
self.recp = recp # not used
self.char_Mv = False
self.i_grade = None # if pure grade mv, grade value
self.grades = None # list of grades in mv
self.is_blade_rep = True # flag for blade representation
self.blade_flg = None # if is_blade is called flag is set
self.versor_flg = None # if is_versor is called flag is set
self.coords = self.Ga.coords
self.title = None
if len(args) == 0: # default constructor 0
self.obj = S.Zero
self.i_grade = 0
kw.reject_remaining()
elif len(args) == 1 and not isinstance(args[0], str): # copy constructor
x = args[0]
if isinstance(x, Mv):
self.obj = x.obj
self.is_blade_rep = x.is_blade_rep
self.i_grade = x.i_grade
else:
if isinstance(x, Expr): # copy constructor for obj expression
self.obj = x
else: # copy constructor for scalar obj expression
self.obj = S(x)
self.is_blade_rep = True
self.characterise_Mv()
kw.reject_remaining()
else:
if isinstance(args[1], str):
make_args = list(args)
mode = make_args.pop(1)
make_func = getattr(Mv, '_make_{}'.format(mode), None)
if make_func is None:
raise ValueError('{!r} is not an allowed multivector type.'.format(mode))
self.obj = make_func(self.Ga, *make_args, **kwargs)
elif isinstance(args[1], int): # args[1] = r (integer) Construct grade r multivector
if args[1] == 0:
# _make_scalar interprets its coefficient argument differently
make_args = list(args)
make_args.pop(1)
self.obj = Mv._make_scalar(self.Ga, *make_args, **kwargs)
else:
self.obj = Mv._make_grade(self.Ga, *args, **kwargs)
else:
raise TypeError("Expected string or int")
if isinstance(args[0], str):
self.title = args[0]
self.characterise_Mv()
def _sympy_(self):
""" Hook used by sympy.sympify """
raise SympifyError(self, TypeError(
"Cannot safely convert an `Mv` instance to a sympy object. "
"Use `mv.obj` to obtain the internal sympy object, but note that "
"this does not overload the geometric operators, and will not "
"track the associated `Ga` instance."
))
################# Multivector member functions #####################
def reflect_in_blade(self, blade: 'Mv') -> 'Mv': # Reflect mv in blade
# See Mv class functions documentation
if blade.is_blade():
self.characterise_Mv()
blade.characterise_Mv()
blade_inv = blade.rev() / blade.norm2()
grade_dict = self.Ga.grade_decomposition(self)
blade_grade = blade.i_grade
reflect = Mv(0, 'scalar', ga=self.Ga)
for grade in list(grade_dict.keys()):
if (grade * (blade_grade + 1)) % 2 == 0:
reflect += blade * grade_dict[grade] * blade_inv
else:
reflect -= blade * grade_dict[grade] * blade_inv
return reflect
else:
raise ValueError(str(blade) + 'is not a blade in reflect_in_blade(self, blade)')
def project_in_blade(self, blade: 'Mv') -> 'Mv':
# See Mv class functions documentation
if blade.is_blade():
blade.characterise_Mv()
blade_inv = blade.rev() / blade.norm2()
return (self < blade) * blade_inv # < is left contraction
else:
raise ValueError(str(blade) + 'is not a blade in project_in_blade(self, blade)')
def rotate_multivector(self, itheta: 'Mv', hint: str = '-'):
Rm = (-itheta/S(2)).exp(hint)
Rp = (itheta/S(2)).exp(hint)
return Rm * self * Rp
def base_rep(self) -> 'Mv':
""" Express as a linear combination of geometric products """
if not self.is_blade_rep:
return self
b = copy.copy(self)
b.obj = self.Ga.blade_to_base_rep(self.obj)
b.is_blade_rep = False
return b
def blade_rep(self) -> 'Mv':
""" Express as a linear combination of blades """
if self.is_blade_rep:
return self
b = copy.copy(self)
b.obj = self.Ga.base_to_blade_rep(self.obj)
b.is_blade_rep = True
return b
def __hash__(self) -> int:
if self.is_scalar():
# ensure we match equality
return hash(self.obj)
else:
return hash((self.Ga, self.obj))
def __eq__(self, A):
if isinstance(A, Mv):
diff = (self - A).expand().simplify()
# diff = (self - A).expand()
return diff.obj == S.Zero
else:
return self.is_scalar() and self.obj == A
"""
def __eq__(self, A):
if not isinstance(A, Mv):
if not self.is_scalar():
return False
if expand(self.obj) == expand(A):
return True
else:
return False
if self.is_blade_rep != A.is_blade_rep:
self = self.blade_rep()
A = A.blade_rep()
coefs, bases = metric.linear_expand(self.obj)
Acoefs, Abases = metric.linear_expand(A.obj)
if len(bases) != len(Abases):
return False
if set(bases) != set(Abases):
return False
for base in bases:
index = bases.index(base)
indexA = Abases.index(base)
if expand(coefs[index]) != expand(Acoefs[index]):
return False
return True
"""
def __neg__(self):
return Mv(-self.obj, ga=self.Ga)
def _arithmetic_op(self, A, op, name: str):
""" Common implementation for + and - """
if isinstance(A, dop._BaseDop):
return NotImplemented
if not isinstance(A, Mv):
return Mv(op(self.obj, A), ga=self.Ga)
if self.Ga != A.Ga:
raise ValueError(
'In {} operation Mv arguments are not from same geometric '
'algebra'.format(name))
if self.is_blade_rep == A.is_blade_rep:
return Mv(op(self.obj, A.obj), ga=self.Ga)
else:
if self.is_blade_rep:
A = A.blade_rep()
else:
self = self.blade_rep()
return Mv(op(self.obj, A.obj), ga=self.Ga)
def __add__(self, A):
return self._arithmetic_op(A, lambda a, b: a + b, '+')
def __radd__(self, A):
return self._arithmetic_op(A, lambda a, b: b + a, '+')
def __sub__(self, A):
return self._arithmetic_op(A, lambda a, b: a - b, '-')
def __rsub__(self, A):
return self._arithmetic_op(A, lambda a, b: b - a, '-')
def __mul__(self, A):
if isinstance(A, dop._BaseDop):
return NotImplemented
if not isinstance(A, Mv):
return Mv(expand(A * self.obj), ga=self.Ga)
if self.Ga != A.Ga:
raise ValueError('In * operation Mv arguments are not from same geometric algebra')
if self.is_scalar():
return Mv(self.obj * A, ga=self.Ga)
if self.is_blade_rep and A.is_blade_rep:
self = self.base_rep()
A = A.base_rep()
selfxA = Mv(self.Ga.mul(self.obj, A.obj), ga=self.Ga)
selfxA.is_blade_rep = False
return selfxA.blade_rep()
elif self.is_blade_rep:
self = self.base_rep()
selfxA = Mv(self.Ga.mul(self.obj, A.obj), ga=self.Ga)
selfxA.is_blade_rep = False
return selfxA.blade_rep()
elif A.is_blade_rep:
A = A.base_rep()
selfxA = Mv(self.Ga.mul(self.obj, A.obj), ga=self.Ga)
selfxA.is_blade_rep = False
return selfxA.blade_rep()
else:
return Mv(self.Ga.mul(self.obj, A.obj), ga=self.Ga)
def __rmul__(self, A):
if isinstance(A, dop._BaseDop):
return NotImplemented
return Mv(expand(A * self.obj), ga=self.Ga)
def __truediv__(self, A):
if isinstance(A, Mv):
return self * A.inv()
else:
return self * (S.One/A)
def __str__(self):
return printer.GaPrinter()._print(self)
def __getitem__(self, key: int) -> 'Mv':
'''
get a specified grade of a multivector
'''
return self.grade(key)
def _sympystr(self, print_obj: printer.GaPrinter) -> str:
# note: this just replaces `self` for the rest of this function
obj = expand(self.obj)
obj = metric.Simp.apply(obj)
self = Mv(obj, ga=self.Ga)
if self.i_grade == 0:
return print_obj._print(self.obj)
if self.is_blade_rep or self.Ga.is_ortho:
base_keys = self.Ga.blades.flat
grade_keys = self.Ga.blades_to_grades_dict
else:
base_keys = self.Ga.bases.flat
grade_keys = self.Ga.bases_to_grades_dict
if isinstance(self.obj, Add): # collect coefficients of bases
if self.obj.is_commutative:
return self.obj
args = self.obj.args
terms = {} # dictionary with base indexes as keys
grade0 = S.Zero
for arg in args:
c, nc = arg.args_cnc()
c = reduce(operator.mul, c, S.One)
if len(nc) > 0:
base = nc[0]
if base in base_keys:
index = base_keys.index(base)
if index in terms:
c_tmp, base, g_keys = terms[index]
terms[index] = (c_tmp + c, base, g_keys)
else:
terms[index] = (c, base, grade_keys[base])
else:
grade0 += c
if grade0 != S.Zero:
terms[-1] = (grade0, S.One, -1)
terms = list(terms.items())
sorted_terms = sorted(terms, key=operator.itemgetter(0)) # sort via base indexes
s = print_obj._print(sorted_terms[0][1][0] * sorted_terms[0][1][1])
if print_obj._settings['galgebra_mv_fmt'] == 3:
s = ' ' + s + '\n'
if print_obj._settings['galgebra_mv_fmt'] == 2:
s = ' ' + s
old_grade = sorted_terms[0][1][2]
for (key, (c, base, grade)) in sorted_terms[1:]:
term = print_obj._print(c * base)
if print_obj._settings['galgebra_mv_fmt'] == 2 and old_grade != grade: # one grade per line
old_grade = grade
s += '\n'
if term[0] == '-':
term = ' - ' + term[1:]
else:
term = ' + ' + term
if print_obj._settings['galgebra_mv_fmt'] == 3: # one base per line
s += term + '\n'
else: # one multivector per line
s += term
if s[-1] == '\n':
s = s[:-1]
return s
else:
return print_obj._print(self.obj)
def _latex(self, print_obj: _LatexPrinter) -> str:
if self.obj == S.Zero:
return ZERO_STR
first_line = True
def append_plus(c_str):
nonlocal first_line
if first_line:
first_line = False
return c_str
else:
c_str = c_str.strip()
if c_str[0] == '-':
return ' ' + c_str
else:
return ' + ' + c_str
# str representation of multivector
# note: this just replaces `self` for the rest of this function
obj = expand(self.obj)
obj = metric.Simp.apply(obj)
self = Mv(obj, ga=self.Ga)
if self.obj == S.Zero:
return ZERO_STR
if self.is_blade_rep or self.Ga.is_ortho:
base_keys = self.Ga.blades.flat
grade_keys = self.Ga.blades_to_grades_dict
else:
base_keys = self.Ga.bases.flat
grade_keys = self.Ga.bases_to_grades_dict
if isinstance(self.obj, Add):
args = self.obj.args
else:
args = [self.obj]
terms = {} # dictionary with base indexes as keys
grade0 = S.Zero
for arg in args:
c, nc = arg.args_cnc(split_1=False)
c = reduce(operator.mul, c, S.One)
if len(nc) > 0:
base = nc[0]
if base in base_keys:
index = base_keys.index(base)
if index in terms:
c_tmp, base, g_keys = terms[index]
terms[index] = (c_tmp + c, base, g_keys)
else:
terms[index] = (c, base, grade_keys[base])
else:
grade0 += c
if grade0 != S.Zero:
terms[-1] = (grade0, S.One, 0)
terms = list(terms.items())
sorted_terms = sorted(terms, key=operator.itemgetter(0)) # sort via base indexes
if len(sorted_terms) == 1 and sorted_terms[0][1][2] == 0: # scalar
return print_obj._print(printer.coef_simplify(sorted_terms[0][1][0]))
lines = []
old_grade = -1
s = ''
for (index, (coef, base, grade)) in sorted_terms:
coef = printer.coef_simplify(coef)
# coef = simplify(coef)
l_coef = print_obj._print(coef)
if l_coef == '1' and base != S.One:
l_coef = ''
if l_coef == '-1' and base != S.One:
l_coef = '-'
if base == S.One:
l_base = ''
else:
l_base = print_obj._print(base)
if isinstance(coef, Add):
cb_str = '\\left ( ' + l_coef + '\\right ) ' + l_base
else:
cb_str = l_coef + ' ' + l_base
if print_obj._settings['galgebra_mv_fmt'] == 3: # One base per line
lines.append(append_plus(cb_str))
elif print_obj._settings['galgebra_mv_fmt'] == 2: # One grade per line
if grade != old_grade:
old_grade = grade
if not first_line:
lines.append(s)
s = append_plus(cb_str)
else:
s += append_plus(cb_str)
else: # One multivector per line
s += append_plus(cb_str)
if print_obj._settings['galgebra_mv_fmt'] == 2:
lines.append(s)
if print_obj._settings['galgebra_mv_fmt'] >= 2:
if len(lines) == 1:
return lines[0]
s = ' \\begin{aligned}[t] '
for line in lines:
s += ' & ' + line + ' \\\\ '
s = s[:-3] + ' \\end{aligned} '
return s
def __xor__(self, A): # wedge (^) product
if isinstance(A, dop._BaseDop):
return NotImplemented
if not isinstance(A, Mv):
return Mv(A * self.obj, ga=self.Ga)
if self.Ga != A.Ga:
raise ValueError('In ^ operation Mv arguments are not from same geometric algebra')
if self.is_scalar():
return self * A
self = self.blade_rep()
A = A.blade_rep()
return Mv(self.Ga.wedge(self.obj, A.obj), ga=self.Ga)
def __rxor__(self, A): # wedge (^) product
if isinstance(A, dop._BaseDop):
return NotImplemented
assert not isinstance(A, Mv)
return Mv(A * self.obj, ga=self.Ga)
def __or__(self, A): # dot (|) product
if isinstance(A, dop._BaseDop):
return NotImplemented
if not isinstance(A, Mv):
return Mv(ga=self.Ga)
if self.Ga != A.Ga:
raise ValueError('In | operation Mv arguments are not from same geometric algebra')
self = self.blade_rep()
A = A.blade_rep()
return Mv(self.Ga.hestenes_dot(self.obj, A.obj), ga=self.Ga)
def __ror__(self, A): # dot (|) product
if isinstance(A, dop._BaseDop):
return NotImplemented
assert not isinstance(A, Mv)
return Mv(ga=self.Ga)
def __pow__(self, n): # Integer power operator
if not isinstance(n, int):
raise ValueError('!!!!Multivector power can only be to integer power!!!!')
result = S.One
for x in range(n):
result *= self
return result
def __lshift__(self, A): # anti-comutator (<<)
return S.Half * (self * A + A * self)
def __rshift__(self, A): # comutator (>>)
return S.Half * (self * A - A * self)
def __rlshift__(self, A): # anti-comutator (<<)
return S.Half * (A * self + self * A)
def __rrshift__(self, A): # comutator (>>)
return S.Half * (A * self - self * A)
def __lt__(self, A): # left contraction (<)
if isinstance(A, Dop):
# Cannot return `NotImplemented` here, as that would call `A > self`
return A.Mul(self, A, op='<')
elif isinstance(A, dop._BaseDop):
raise TypeError(
"'<' not supported between instances of 'Mv' and {!r}"
.format(type(A).__name__)
)
if not isinstance(A, Mv): # sympy scalar
return Mv(A * self.scalar(), ga=self.Ga)
if self.Ga != A.Ga:
raise ValueError('In < operation Mv arguments are not from same geometric algebra')
self = self.blade_rep()
A = A.blade_rep()
return Mv(self.Ga.left_contract(self.obj, A.obj), ga=self.Ga)
def __gt__(self, A): # right contraction (>)
if isinstance(A, Dop):
# Cannot return `NotImplemented` here, as that would call `A < self`
return A.Mul(self, A, op='>')
elif isinstance(A, dop._BaseDop):
raise TypeError(
"'>' not supported between instances of 'Mv' and {!r}"
.format(type(A).__name__)
)
if not isinstance(A, Mv): # sympy scalar
return Mv(A * self.obj, ga=self.Ga)
if self.Ga != A.Ga:
raise ValueError('In > operation Mv arguments are not from same geometric algebra')
self = self.blade_rep()
A = A.blade_rep()
return Mv(self.Ga.right_contract(self.obj, A.obj), ga=self.Ga)
def collect(self, deep=False) -> 'Mv':
"""
group coeffients of blades of multivector
so there is only one coefficient per grade
"""
""" # dead code
self.obj = expand(self.obj)
if self.is_blade_rep or Mv.Ga.is_ortho:
c = self.Ga.blades.flat
else:
c = self.Ga.bases.flat
self.obj = self.obj.collect(c)
return self
"""
obj_dict = {}
for coef, base in metric.linear_expand_terms(self.obj):
if base in list(obj_dict.keys()):
obj_dict[base] += coef
else:
obj_dict[base] = coef
obj = S.Zero
for base in list(obj_dict.keys()):
if deep:
obj += collect(obj_dict[base])*base
else:
obj += obj_dict[base]*base
return Mv(obj, ga=self.Ga)
def is_scalar(self) -> bool:
grades = self.Ga.grades(self.obj)
return grades == [0]
def is_vector(self) -> bool:
grades = self.Ga.grades(self.obj)
return grades == [1]
def is_blade(self) -> bool:
"""
True is self is blade, otherwise False
sets self.blade_flg and returns value
"""
if self.blade_flg is not None:
return self.blade_flg
else:
if self.is_versor():
if self.i_grade is not None:
self.blade_flg = True
else:
self.blade_flg = False
else:
self.blade_flg = False
return self.blade_flg
def is_base(self) -> bool:
coefs, _bases = metric.linear_expand(self.obj)
return coefs == [S.One]
def is_versor(self) -> bool:
"""
Test for versor (geometric product of vectors)
This follows Leo Dorst's test for a versor.
Leo Dorst, 'Geometric Algebra for Computer Science,' p.533
Sets self.versor_flg and returns value
"""
if self.versor_flg is not None:
return self.versor_flg
self.characterise_Mv()
self.versor_flg = False
self_rev = self.rev()
# see if self*self.rev() is a scalar
test = self*self_rev
if not test.is_scalar():
return self.versor_flg
# see if self*x*self.rev() returns a vector for x an arbitrary vector
test = self * self.Ga._XOX * self.rev()
self.versor_flg = test.is_vector()
return self.versor_flg
def is_zero(self) -> bool:
return self.obj == 0
def scalar(self) -> Expr:
""" return scalar part of multivector as sympy expression """
return self.Ga.scalar_part(self.obj)
def get_grade(self, r: int) -> 'Mv':
""" return r-th grade of multivector as a multivector """
return Mv(self.Ga.get_grade(self.obj, r), ga=self.Ga)
def components(self) -> List['Mv']:
cb = metric.linear_expand_terms(self.obj)
cb = sorted(cb, key=lambda x: self.Ga.blades.flat.index(x[1]))
return [self.Ga.mv(coef * base) for coef, base in cb]
def get_coefs(self, grade: int) -> List[Expr]:
"""
Like ``blade_coefs(self.Ga.mv_blades[grade])``, but requires all
components to be of that grade.
Raises
------
ValueError:
If the multivector is not of the given grade.
"""
blade_lst = self.Ga.blades[grade]
coef_lst = [S.Zero] * len(blade_lst)
for coef, blade in metric.linear_expand_terms(self.obj):
if coef == S.Zero:
continue # TODO: why does expansion return this?
try:
base_i = blade_lst.index(blade)
except ValueError:
raise ValueError(
"MultiVector has a {} component which is not grade {}"
.format(blade, grade)
) from None
coef_lst[base_i] += coef
return coef_lst
def blade_coefs(self, blade_lst: List['Mv'] = None) -> List[Expr]:
"""
For a multivector, A, and a list of basis blades, blade_lst return
a list (sympy expressions) of the coefficients of each basis blade
in blade_lst
"""
if blade_lst is None:
blade_lst = self.Ga.mv_blades.flat
else:
for blade in blade_lst:
if not blade.is_base() or not blade.is_blade():
raise ValueError("%s expression isn't a basis blade" % blade)
blade_lst = [x.obj for x in blade_lst]
coefs, bases = metric.linear_expand(self.obj)
coef_lst = []
for blade in blade_lst:
if blade in bases:
coef_lst.append(coefs[bases.index(blade)])
else:
coef_lst.append(S.Zero)
return coef_lst
def proj(self, bases_lst: List['Mv']) -> 'Mv':
"""
Project multivector onto a given list of bases. That is find the
part of multivector with the same bases as in the bases_lst.
"""
bases_lst = [x.obj for x in bases_lst]
obj = 0
for coef, base in metric.linear_expand_terms(self.obj):
if base in bases_lst:
obj += coef * base
return Mv(obj, ga=self.Ga)
def dual(self) -> 'Mv':
mode = self.Ga.dual_mode_value
sign = S.One
if '-' in mode:
sign = -sign
if 'Iinv' in mode:
I = self.Ga.i_inv
else:
I = self.Ga.i
if mode[0] == '+' or mode[0] == '-':
return sign * I * self
else:
return sign * self * I
def even(self) -> 'Mv':
""" return even parts of multivector """
return Mv(self.Ga.even_odd(self.obj, True), ga=self.Ga)
def odd(self) -> 'Mv':
""" return odd parts of multivector """
return Mv(self.Ga.even_odd(self.obj, False), ga=self.Ga)
def rev(self) -> 'Mv':
self = self.blade_rep()
return Mv(self.Ga.reverse(self.obj), ga=self.Ga)
__invert__ = rev # allow `~x` to call x.rev()
def diff(self, coord) -> 'Mv':
if self.Ga.coords is None:
obj = diff(self.obj, coord)
elif coord not in self.Ga.coords:
if self.Ga.par_coords is None:
obj = diff(self.obj, coord)
elif coord not in self.Ga.par_coords:
obj = diff(self.obj, coord)
else:
obj = diff(self.obj, coord)
for x_coord in self.Ga.coords:
f = self.Ga.par_coords[x_coord]
if f != S.Zero:
tmp1 = self.Ga.pDiff(self.obj, x_coord)
tmp2 = diff(f, coord)
obj += tmp1 * tmp2
else:
obj = self.Ga.pDiff(self.obj, coord)
return Mv(obj, ga=self.Ga)
def pdiff(self, var) -> 'Mv':
return Mv(self.Ga.pDiff(self.obj, var), ga=self.Ga)
def Grad(self, coords, mode: str = '*', left: bool = True) -> 'Mv':
"""
Returns various derivatives (``*``, ``^``, ``|``, ``<``, ``>``) of
multivector functions with respect to arbitrary coordinates, 'coords'.
This would be
used where you have a multivector function of both the basis
coordinate set and and auxiliary coordinate set. Consider for
example a linear transformation in which the matrix coefficients
depend upon the manifold coordinates, but the vector being
transformed does not and you wish to take the divergence of the
linear transformation with respect to the linear argument.
"""
return Mv(self.Ga.Diff(self, mode, left, coords=coords), ga=self.Ga)
def exp(self, hint: str = '-') -> 'Mv': # Calculate exponential of multivector
"""
Only works if square of multivector is a scalar. If square is a
number we can determine if square is > or < zero and hence if
one should use trig or hyperbolic functions in expansion. If
square is not a number use 'hint' to determine which type of
functions to use in expansion
"""
self = self.blade_rep()
self_sq = self * self
if self_sq.is_scalar():
sq = simplify(self_sq.obj) # sympy expression for self**2
if sq == S.Zero: # sympy expression for self**2 = 0
return self + S.One
coefs, bases = metric.linear_expand(self.obj)
if len(coefs) == 1: # Exponential of scalar * base
base = bases[0]
base_Mv = self.Ga.mv(base)
base_sq = (base_Mv*base_Mv).scalar()
if hint == '-': # base^2 < 0
base_n = sqrt(-base_sq)
return self.Ga.mv(cos(base_n*coefs[0]) + sin(base_n*coefs[0])*(bases[0]/base_n))
else: # base^2 > 0
base_n = sqrt(base_sq)
return self.Ga.mv(cosh(base_n*coefs[0]) + sinh(base_n*coefs[0])*(bases[0]/base_n))
if sq.is_number: # Square is number, can test for sign
if sq > S.Zero:
norm = sqrt(sq)
value = self.obj / norm
tmp = Mv(cosh(norm) + sinh(norm) * value, ga=self.Ga)
tmp.is_blade_rep = True
return tmp
else:
norm = sqrt(-sq)
value = self.obj / norm
tmp = Mv(cos(norm) + sin(norm) * value, ga=self.Ga)
tmp.is_blade_rep = True
return tmp
else:
if hint == '+':
norm = simplify(sqrt(sq))
value = self.obj / norm
tmp = Mv(cosh(norm) + sinh(norm) * value, ga=self.Ga)
tmp.is_blade_rep = True
return tmp
else:
norm = simplify(sqrt(-sq))
value = self.obj / norm
tmp = Mv(cos(norm) + sin(norm) * value, ga=self.Ga)
tmp.is_blade_rep = True
return tmp
else:
raise ValueError('"' + str(self) + '**2" is not a scalar in exp.')
def set_coef(self, igrade: int, ibase: int, value: Expr) -> None:
if self.blade_rep:
base = self.Ga.blades[igrade][ibase]
else:
base = self.Ga.bases[igrade][ibase]
coefs, bases = metric.linear_expand(self.obj)
bases_lst = list(bases) # python 2.5
if base in bases:
self.obj += (value - coefs[bases_lst.index(base)]) * base
else:
self.obj += value * base
def Fmt(self, fmt: int = 1, title: str = None) -> printer.GaPrintable:
"""
Set format for printing of multivectors
* `fmt=1` - One multivector per line
* `fmt=2` - One grade per line
* `fmt=3` - one base per line
Usage for multivector ``A`` example is::
A.Fmt('2', 'A')
output is::
'A = '+str(A)
with one grade per line. Works for both standard printing and
for latex.
"""
if fmt is not None:
obj = printer._WithSettings(self, dict(galgebra_mv_fmt=fmt))
else:
obj = self
return printer._FmtResult(obj, title)
def _repr_latex_(self) -> str:
# overloaded to include the inferred title
if self.title is not None:
return printer._FmtResult(self, self.title)._repr_latex_()
return super()._repr_latex_()
def norm2(self) -> Expr:
reverse = self.rev()
product = self * reverse
if product.is_scalar():
return product.scalar()
else:
raise TypeError('"(' + str(product) + ')**2" is not a scalar in norm2.')
def norm(self, hint: str = '+') -> Expr:
"""
If A is a multivector and A*A.rev() is a scalar then::
A.norm() == sqrt(Abs(A*A.rev()))
The problem in simplifying the norm is that if ``A`` is symbolic
you don't know if ``A*A.rev()`` is positive or negative. The use
of the hint argument is as follows:
======= ========================
hint ``A.norm()``
======= ========================
``'+'`` ``sqrt(A*A.rev())``
``'-'`` ``sqrt(-A*A.rev())``
``'0'`` ``sqrt(Abs(A*A.rev()))``
======= ========================
The default ``hint='+'`` is correct for vectors in a Euclidean vector
space. For bivectors in a Euclidean vector space use ``hint='-'``. In
a mixed signature space all bets are off for the norms of symbolic
expressions.
"""
reverse = self.rev()
product = self * reverse
if product.is_scalar():
product = product.scalar()
if product.is_number:
if product >= S.Zero:
return sqrt(product)
else:
return sqrt(-product)
else:
if hint == '+':
return metric.square_root_of_expr(product)
elif hint == '-':
return metric.square_root_of_expr(-product)
else:
return sqrt(Abs(product))
else:
raise TypeError('"(' + str(product) + ')" is not a scalar in norm.')
__abs__ = norm # allow `abs(x)` to call z.norm()
def inv(self) -> 'Mv':
if self.is_scalar(): # self is a scalar
return self.Ga.mv(S.One/self.obj)
self_sq = self * self
if self_sq.is_scalar(): # self*self is a scalar
"""
if self_sq.scalar() == S.Zero:
raise ValueError('!!!!In multivector inverse, A*A is zero!!!!')
"""
return (S.One/self_sq.obj)*self
self_rev = self.rev()
self_self_rev = self * self_rev
if self_self_rev.is_scalar(): # self*self.rev() is a scalar
"""
if self_self_rev.scalar() == S.Zero:
raise ValueError('!!!!In multivector inverse A*A.rev() is zero!!!!')
"""
return (S.One/self_self_rev.obj) * self_rev
raise TypeError('In inv() for self =' + str(self) + 'self, or self*self or self*self.rev() is not a scalar')
def func(self, fct) -> 'Mv': # Apply function, fct, to each coefficient of multivector
s = S.Zero
for coef, base in metric.linear_expand_terms(self.obj):
s += fct(coef) * base
fct_self = Mv(s, ga=self.Ga)
fct_self.characterise_Mv()
return fct_self
def trigsimp(self) -> 'Mv':
return self.func(trigsimp)
def simplify(self, modes=simplify) -> 'Mv':
"""
Simplify a multivector by scalar (sympy) simplifications.
`modes` is an operation or sequence of operations to apply to the the
coefficients of a multivector expansion.
"""
if not isinstance(modes, (list, tuple)):
modes = [modes]
obj = S.Zero
for coef, base in metric.linear_expand_terms(self.obj):
for mode in modes:
coef = mode(coef)
obj += coef * base
return Mv(obj, ga=self.Ga)
def subs(self, *args, **kwargs) -> 'Mv':
""" Perform a substitution on each coefficient separately """
obj = sum((
coef.subs(*args, **kwargs) * base for coef, base in metric.linear_expand_terms(self.obj)
), S.Zero)
return Mv(obj, ga=self.Ga)
def expand(self) -> 'Mv':
obj = sum((
expand(coef) * base for coef, base in metric.linear_expand_terms(self.obj)
), S.Zero)
return Mv(obj, ga=self.Ga)
def list(self) -> List[Expr]:
return self.blade_coefs(self.Ga.mv_blades[1])
def grade(self, r=0) -> 'Mv':
return self.get_grade(r)
def pure_grade(self) -> int:
"""
For pure grade return grade. If not pure grade return negative
of maximum grade
"""
self.characterise_Mv()
if self.i_grade is not None:
return self.i_grade
return -self.grades[-1]
def _eval_derivative_n_times(self, x, n) -> 'Mv':
for i in range(n):
self = self.Ga.pDiff(self, x)
return self
def compare(A: Mv, B: Mv) -> Union[Expr, int]:
"""
Determine if ``B = c*A`` where c is a scalar. If true return c
otherwise return 0.
"""
if isinstance(A, Mv) and isinstance(B, Mv):
Acoefs, Abases = metric.linear_expand(A.obj)
Bcoefs, Bbases = metric.linear_expand(B.obj)
if len(Acoefs) != len(Bcoefs):
return 0
if Abases != Bbases:
return 0
if Bcoefs[0] != 0 and Abases[0] == Bbases[0]:
c = simplify(Acoefs[0]/Bcoefs[0])
print('c =', c)
else:
return 0
for acoef, abase, bcoef, bbase in zip(Acoefs[1:], Abases[1:], Bcoefs[1:], Bbases[1:]):
print(acoef, '\n', abase, '\n', bcoef, '\n', bbase)
if bcoef != 0 and abase == bbase:
print('c-a/b =', simplify(c-(acoef/bcoef)))
if simplify(acoef/bcoef) != c:
return 0
else:
pass
else:
return 0
return c
else:
raise TypeError('In compare both arguments are not multivectors\n')
################# Multivector Differential Operator Class ##############
class Dop(dop._BaseDop):
r"""
Differential operator class for multivectors. The operators are of
the form
.. math:: D = D^{i_{1}...i_{n}}\partial_{i_{1}...i_{n}}
where the :math:`D^{i_{1}...i_{n}}` are multivector functions of the coordinates
:math:`x_{1},...,x_{n}` and :math:`\partial_{i_{1}...i_{n}}` are partial derivative
operators
.. math:: \partial_{i_{1}...i_{n}} =
\frac{\partial^{i_{1}+...+i_{n}}}{\partial{x_{1}^{i_{1}}}...\partial{x_{n}^{i_{n}}}}.
If :math:`*` is any multivector multiplicative operation then the operator D
operates on the multivector function :math:`F` by the following definitions
.. math:: D*F = D^{i_{1}...i_{n}}*\partial_{i_{1}...i_{n}}F
returns a multivector and
.. math:: F*D = F*D^{i_{1}...i_{n}}\partial_{i_{1}...i_{n}}
returns a differential operator. If the :attr:`cmpflg` in the operator is
set to ``True`` the operation returns
.. math:: F*D = (\partial_{i_{1}...i_{n}}F)*D^{i_{1}...i_{n}}
a multivector function. For example the representation of the grad
operator in 3d would be:
.. math::
D^{i_{1}...i_{n}} &= [e_x,e_y,e_z] \\
\partial_{i_{1}...i_{n}} &= [(1,0,0),(0,1,0),(0,0,1)].
See LaTeX documentation for definitions of operator algebraic
operations ``+``, ``-``, ``*``, ``^``, ``|``, ``<``, and ``>``.
Attributes
----------
ga : ~galgebra.ga.Ga
Associated geometric algebra
cmpflg : bool
Complement flag
terms : list of tuples
"""
def __init_from_coef_and_pdop(self, coefs: List[Any], pdiffs: List['dop.Pdop']):
if len(coefs) != len(pdiffs):
raise ValueError('In Dop.__init__ coefficent list and Pdop list must be same length.')
self.terms = tuple(zip(coefs, pdiffs))
def __init_from_terms(self, terms: Union[
List[Tuple[Mv, dop.Pdop]],
List[Tuple[dop.Sdop, Mv]],
]):
if len(terms) == 0:
self.terms = ()
elif all(
isinstance(coef, Mv) and isinstance(pdiff, dop.Pdop)
for coef, pdiff in terms
):
# Mv expansion [(Mv, Pdop)]
self.terms = tuple(terms)
elif all(
isinstance(sdop, dop.Sdop) and isinstance(coef, Mv)
for sdop, coef in terms
):
# Sdop expansion [(Sdop, Mv)]
self.terms = dop._consolidate_terms(
(coef * mv, pdiff)
for (sdop, mv) in terms
for (coef, pdiff) in sdop.terms
)
else:
raise TypeError(
'In Dop.__init__ terms are neither (Mv, Pdop) pairs or '
'(Sdop, Mv) pairs, got {}'.format(terms))
def __init__(self, *args, ga: 'Ga', cmpflg: bool = False, debug: bool = False) -> None:
"""
Parameters
----------
ga :
Associated geometric algebra
cmpflg : bool
Complement flag for Dop
debug : bool
True to print out debugging information
"""
if ga is None:
raise ValueError('ga argument to Dop() must not be None')
self.cmpflg = cmpflg
self.Ga = ga
if len(args) == 2:
self.__init_from_coef_and_pdop(*args)
elif len(args) == 1:
self.__init_from_terms(*args)
else:
# count include self, as python usually does
raise TypeError(
"Dop() takes from 1 to 2 positional arguments but {} were "
"given".format(len(args)))
def simplify(self, modes=simplify) -> 'Dop':
"""
Simplify each multivector coefficient of a partial derivative
"""
return Dop(
[(coef.simplify(modes=modes), pd) for coef, pd in self.terms],
ga=self.Ga, cmpflg=self.cmpflg
)
def consolidate_coefs(self) -> 'Dop':
"""
Remove zero coefs and consolidate coefs with repeated pdiffs.
"""
return Dop(dop._consolidate_terms(self.terms), ga=self.Ga, cmpflg=self.cmpflg)
@staticmethod
def Add(dop1, dop2):
if isinstance(dop1, Dop) and isinstance(dop2, Dop):
if dop1.Ga != dop2.Ga:
raise ValueError('In Dop.Add Dop arguments are not from same geometric algebra')
if dop1.cmpflg != dop2.cmpflg:
raise ValueError('In Dop.Add complement flags have different values: %s vs. %s' % (dop1.cmpflg, dop2.cmpflg))
return Dop(dop._merge_terms(dop1.terms, dop2.terms), cmpflg=dop1.cmpflg, ga=dop1.Ga)
else:
# convert values to multiplicative operators
if isinstance(dop1, Dop):
if not isinstance(dop2, Mv):
dop2 = dop1.Ga.mv(dop2)
dop2 = Dop([(dop2, dop.Pdop({}))], cmpflg=dop1.cmpflg, ga=dop1.Ga)
elif isinstance(dop2, Dop):
if not isinstance(dop1, Mv):
dop1 = dop2.Ga.mv(dop1)
dop1 = Dop([(dop1, dop.Pdop({}))], cmpflg=dop2.cmpflg, ga=dop2.Ga)
else:
raise TypeError("Neither argument is a Dop instance")
return Dop.Add(dop1, dop2)
def __add__(self, dop):
return Dop.Add(self, dop)
def __radd__(self, dop):
return Dop.Add(dop, self)
def __neg__(self):
return Dop(
[(-coef, pdiff) for coef, pdiff in self.terms],
ga=self.Ga, cmpflg=self.cmpflg
)
def __sub__(self, dop):
return Dop.Add(self, -dop)
def __rsub__(self, dop):
return Dop.Add(dop, -self)
@staticmethod
def Mul(dopl, dopr, op='*'): # General multiplication of Dop's
# cmpflg is True if the Dop operates on the left argument and
# False if the Dop operates on the right argument
if isinstance(dopl, Dop) and isinstance(dopr, Dop):
if dopl.Ga != dopr.Ga:
raise ValueError('In Dop.Mul Dop arguments are not from same geometric algebra')
ga = dopl.Ga
if dopl.cmpflg != dopr.cmpflg:
raise ValueError('In Dop.Mul Dop arguments do not have same cmplfg')
if not dopl.cmpflg: # dopl and dopr operate on right argument
product = sum((
Dop.Mul(coef, pdiff(dopr), op=op)
for coef, pdiff in dopl.terms
), Dop([], ga=ga, cmpflg=False))
else: # dopl and dopr operate on left argument
product = sum((
Dop.Mul(pdiff(dopl), coef, op=op)
for coef, pdiff in dopr.terms
), Dop([], ga=ga, cmpflg=True))
else:
if not isinstance(dopl, Dop): # dopl is a scalar or Mv and dopr is Dop
if isinstance(dopl, Mv) and dopl.Ga != dopr.Ga:
raise ValueError('In Dop.Mul Dop arguments are not from same geometric algebra')
else:
dopl = dopr.Ga.mv(dopl)
ga = dopl.Ga
if not dopr.cmpflg: # dopr operates on right argument
product = Dop([
(Mv.Mul(dopl, coef, op=op), pdiff)
for coef, pdiff in dopr.terms
], ga=ga)
else:
return sum([
Mv.Mul(pdiff(dopl), coef, op=op)
for coef, pdiff in dopr.terms
], Mv(0, ga=ga))
else: # dopr is a scalar or a multivector
if isinstance(dopr, Mv) and dopl.Ga != dopr.Ga:
raise ValueError('In Dop.Mul Dop arguments are not from same geometric algebra')
ga = dopl.Ga
if not dopl.cmpflg: # dopl operates on right argument
return sum([
Mv.Mul(coef, pdiff(dopr), op=op)
for coef, pdiff in dopl.terms
], Mv(0, ga=ga))
else:
product = Dop([
(Mv.Mul(coef, dopr, op=op), pdiff)
for coef, pdiff in dopl.terms
], ga=ga, cmpflg=True) # returns Dop complement
return product.consolidate_coefs()
def TSimplify(self):
return Dop([
(metric.Simp.apply(coef), pdiff) for coef, pdiff in self.terms
], ga=self.Ga)
def __truediv__(self, dopr):
if isinstance(dopr, (Dop, Mv)):
raise TypeError('In Dop.__truediv__ dopr must be a sympy scalar.')
return Dop([
(coef / dopr, pdiff) for coef, pdiff in self.terms
], ga=self.Ga, cmpflg=self.cmpflg)
def __mul__(self, dopr): # * geometric product
return Dop.Mul(self, dopr, op='*')
def __rmul__(self, dopl): # * geometric product
return Dop.Mul(dopl, self, op='*')
def __xor__(self, dopr): # ^ outer product
return Dop.Mul(self, dopr, op='^')
def __rxor__(self, dopl): # ^ outer product
return Dop.Mul(dopl, self, op='^')
def __or__(self, dopr): # | inner product
return Dop.Mul(self, dopr, op='|')
def __ror__(self, dopl): # | inner product
return Dop.Mul(dopl, self, op='|')
def __lt__(self, dopr): # < left contraction
return Dop.Mul(self, dopr, op='<')
def __gt__(self, dopr): # > right contraction
return Dop.Mul(self, dopr, op='>')
def __eq__(self, other):
if isinstance(other, Dop):
if self.Ga != other.Ga:
return NotImplemented
diff = self - other
return len(diff.terms) == 0
else:
return NotImplemented
def is_scalar(self) -> bool:
return all(
not isinstance(coef, Mv) or coef.is_scalar()
for coef, pdiff in self.terms
)
def components(self) -> Tuple['Dop', ...]:
return tuple(
Dop([(sdop, Mv(base, ga=self.Ga))], ga=self.Ga)
for sdop, base in self.Dop_mv_expand()
)
def Dop_mv_expand(self, modes=None) -> List[Tuple[Expr, Expr]]:
coefs = []
bases = []
self.consolidate_coefs()
for coef, pdiff in self.terms:
if isinstance(coef, Mv) and not coef.is_scalar():
for mv_coef, mv_base in metric.linear_expand_terms(coef.obj):
if mv_base in bases:
index = bases.index(mv_base)
coefs[index] += dop.Sdop([(mv_coef, pdiff)])
else:
bases.append(mv_base)
coefs.append(dop.Sdop([(mv_coef, pdiff)]))
else:
if isinstance(coef, Mv):
mv_coef = coef.obj
else:
mv_coef = coef
if S.One in bases:
index = bases.index(S.One)
coefs[index] += dop.Sdop([(mv_coef, pdiff)])
else:
bases.append(S.One)
coefs.append(dop.Sdop([(mv_coef, pdiff)]))
if modes is not None:
for i in range(len(coefs)):
coefs[i] = coefs[i].simplify(modes)
terms = list(zip(coefs, bases))
return sorted(terms, key=lambda x: self.Ga.blades.flat.index(x[1]))
def _sympystr(self, print_obj: _StrPrinter) -> str:
if len(self.terms) == 0:
return ZERO_STR
mv_terms = self.Dop_mv_expand(modes=simplify)
s = ''
for sdop, base in mv_terms:
str_base = print_obj._print(base)
str_sdop = print_obj._print(sdop)
if base == S.One:
s += str_sdop
else:
if len(sdop.terms) > 1:
if self.cmpflg:
s += '(' + str_sdop + ')*' + str_base
else:
s += str_base + '*(' + str_sdop + ')'
else:
if str_sdop[0] == '-' and not isinstance(sdop.terms[0][0], Add):
if self.cmpflg:
s += str_sdop + '*' + str_base
else:
s += '-' + str_base + '*' + str_sdop[1:]
else:
if self.cmpflg:
s += str_sdop + '*' + str_base
else:
s += str_base + '*' + str_sdop
s += ' + '
s = s.replace('+ -', '-')
return s[:-3]
def _latex(self, print_obj: _LatexPrinter) -> str:
if len(self.terms) == 0:
return ZERO_STR
self.consolidate_coefs()
mv_terms = self.Dop_mv_expand(modes=simplify)
s = ''
for sdop, base in mv_terms:
str_base = print_obj._print(base)
str_sdop = print_obj._print(sdop)
if base == S.One:
s += str_sdop
else:
if str_sdop == '1':
s += str_base
if str_sdop == '-1':
s += '-' + str_base
if str_sdop[1:] != '1':
s += ' ' + str_sdop[1:]
else:
if len(sdop.terms) > 1:
if self.cmpflg:
s += r'\left ( ' + str_sdop + r'\right ) ' + str_base
else:
s += str_base + ' ' + r'\left ( ' + str_sdop + r'\right ) '
else:
if str_sdop[0] == '-' and not isinstance(sdop.terms[0][0], Add):
if self.cmpflg:
s += str_sdop + str_base
else:
s += '-' + str_base + ' ' + str_sdop[1:]
else:
if self.cmpflg:
s += str_sdop + ' ' + str_base
else:
s += str_base + ' ' + str_sdop
s += ' + '
s = s.replace('+ -', '-')
return s[:-3]
def Fmt(self, fmt: int = 1, title: str = None) -> printer.GaPrintable:
if fmt is not None:
obj = printer._WithSettings(self, dict(galgebra_mv_fmt=fmt))
else:
obj = self
return printer._FmtResult(obj, title)
def _eval_derivative_n_times(self, x, n):
return Dop(dop._eval_derivative_n_times_terms(self.terms, x, n), cmpflg=self.cmpflg, ga=self.Ga)
################################# Alan Macdonald's additions #########################
def Nga(x, prec=5):
"""
Like :func:`sympy.N`, but also works on multivectors
For multivectors with coefficients that contain floating point numbers, this
rounds all these numbers to a precision of ``prec`` and returns the rounded
multivector.
"""
if isinstance(x, Mv):
return Mv(Nsympy(x.obj, prec), ga=x.Ga)
else:
return Nsympy(x, prec)
def printeigen(M): # Print eigenvalues, multiplicities, eigenvectors of M.
evects = M.eigenvects()
for i in range(len(evects)): # i iterates over eigenvalues
print(('Eigenvalue =', evects[i][0], ' Multiplicity =', evects[i][1], ' Eigenvectors:'))
for j in range(len(evects[i][2])): # j iterates over eigenvectors of a given eigenvalue
result = '['
for k in range(len(evects[i][2][j])): # k iterates over coordinates of an eigenvector
result += str(trigsimp(evects[i][2][j][k]).evalf(3))
if k != len(evects[i][2][j]) - 1:
result += ', '
result += '] '
print(result)
def printGS(M, norm=False): # Print Gram-Schmidt output.
from sympy import GramSchmidt
global N
N = GramSchmidt(M, norm)
result = '[ '
for i in range(len(N)):
result += '['
for j in range(len(N[0])):
result += str(trigsimp(N[i][j]).evalf(3))
if j != len(N[0]) - 1:
result += ', '
result += '] '
if j != len(N[0]) - 1:
result += ' '
result += ']'
print(result)
def printrref(matrix, vars="xyzuvwrs"): # Print rref of matrix with variables.
rrefmatrix = matrix.rref()[0]
rows, cols = rrefmatrix.shape
if len(vars) < cols - 1:
print('Not enough variables.')
return
for i in range(rows):
result = ''
for j in range(cols - 1):
result += str(rrefmatrix[i, j]) + vars[j]
if j != cols - 2:
result += ' + '
result += ' = ' + str(rrefmatrix[i, cols - 1])
print(result)
def com(A, B):
raise ImportError(
"""mv.com is removed, please use galgebra.ga.Ga.com(A, B) instead.""")
def correlation(u, v, dec=3): # Compute the correlation coefficient of vectors u and v.
rows, cols = u.shape
uave = 0
vave = 0
for i in range(rows):
uave += u[i]
vave += v[i]
uave = uave / rows
vave = vave / rows
ulocal = u[:, :] # Matrix copy
vlocal = v[:, :]
for i in range(rows):
ulocal[i] -= uave
vlocal[i] -= vave
return ulocal.dot(vlocal) / (ulocal.norm() * vlocal.norm()). evalf(dec)
def cross(v1: Mv, v2: Mv) -> Mv:
r"""
If ``v1`` and ``v2`` are 3-dimensional Euclidean vectors, compute the vector
cross product :math:`v_{1}\times v_{2} = -I{\lp {v_{1}{\wedge}v_{2}} \rp }`.
"""
if v1.is_vector() and v2.is_vector() and v1.Ga == v2.Ga and v1.Ga.n == 3:
return -v1.Ga.I() * (v1 ^ v2)
else:
raise ValueError(str(v1) + ' and ' + str(v2) + ' not compatible for cross product.')
def dual(A: Mv) -> Mv:
""" Equivalent to :meth:`Mv.dual` """
if isinstance(A, Mv):
return A.dual()
else:
raise ValueError('A not a multivector in dual(A)')
def even(A: Mv) -> Mv:
""" Equivalent to :meth:`Mv.even` """
if not isinstance(A, Mv):
raise ValueError('A = ' + str(A) + ' not a multivector in even(A).')
return A.even()
def odd(A: Mv) -> Mv:
""" Equivalent to :meth:`Mv.odd` """
if not isinstance(A, Mv):
raise ValueError('A = ' + str(A) + ' not a multivector in even(A).')
return A.odd()
def exp(A: Union[Mv, Expr], hint: str = '-') -> Union[Mv, Expr]:
"""
If ``A`` is a multivector then ``A.exp(hint)`` is returned.
If ``A`` is a *sympy* expression the *sympy* expression :math:`e^{A}` is returned (see :func:`sympy.exp`).
"""
if isinstance(A, Mv):
return A.exp(hint)
else:
return sympy_exp(A)
def grade(A: Mv, r: int = 0) -> Mv:
""" Equivalent to :meth:`Mv.grade` """
if isinstance(A, Mv):
return A.grade(r)
else:
raise ValueError('A not a multivector in grade(A, r)')
def inv(A: Mv) -> Mv:
""" Equivalent to :meth:`Mv.inv` """
if not isinstance(A, Mv):
raise ValueError('A = ' + str(A) + ' not a multivector in inv(A).')
return A.inv()
def norm(A: Mv, hint: str = '+') -> Expr:
""" Equivalent to :meth:`Mv.norm` """
if isinstance(A, Mv):
return A.norm(hint=hint)
else:
raise ValueError('A not a multivector in norm(A)')
def norm2(A: Mv) -> Expr:
""" Equivalent to :meth:`Mv.norm2` """
if isinstance(A, Mv):
return A.norm2()
else:
raise ValueError('A not a multivector in norm(A)')
def proj(B: Mv, A: Mv) -> Mv:
""" Equivalent to :meth:`Mv.project_in_blade` """
if isinstance(A, Mv):
return A.project_in_blade(B)
else:
raise ValueError('A not a multivector in proj(B, A)')
def rot(itheta: Mv, A: Mv, hint: str = '-') -> Mv:
"""
Equivalent to ``A.rotate_multivector(itheta, hint)`` where ``itheta`` is the bi-vector blade defining the rotation.
For the use of ``hint`` see the method :meth:`Mv.rotate_multivector`.
"""
if isinstance(A, Mv):
return A.rotate_multivector(itheta, hint)
else:
raise ValueError('A not a multivector in rotate(A, itheta)')
def refl(B: Mv, A: Mv) -> Mv:
r"""
Reflect multivector :math:`A` in blade :math:`B`.
If :math:`s` is grade of :math:`B` returns :math:`\sum_{r}(-1)^{s(r+1)}B{\left < {A} \right >}_{r}B^{-1}`.
Equivalent to :meth:`Mv.reflect_in_blade`
"""
if isinstance(A, Mv):
return A.reflect_in_blade(B)
else:
raise ValueError('A not a multivector in reflect(B, A)')
def rev(A: Mv) -> Mv:
""" Equivalent to :meth:`Mv.rev` """
if isinstance(A, Mv):
return A.rev()
else:
raise ValueError('A not a multivector in rev(A)')
def scalar(A: Mv) -> Expr:
""" Equivalent to :meth:`Mv.scalar` """
if not isinstance(A, Mv):
raise ValueError('A = ' + str(A) + ' not a multivector in inv(A).')
return A.scalar()