def mp_solve(f, p, x0=0.01, limits=None, method='muller'):
if not limits:
return mp.findroot(lambda x: f(x, p=p), x0, solver=method)
else:
if method == 'muller':
method = 'anderson'
return mp.findroot(lambda x: f(x, p=p), limits, solver=method)
def mp_solve(f, x0=0.01, limits=None, method="muller"):
if not limits:
return mp.findroot(f, x0, solver=method)
else:
if method == "muller":
method = "anderson"
return mp.findroot(f, limits, solver=method)
def _eval_evalf(self, prec):
"""Evaluate this complex root to the given precision. """
_prec, mp.prec = mp.prec, prec
try:
func = lambdify(self.poly.gen, self.expr)
interval = self._get_interval()
refined = False
while True:
if self.is_real:
x0 = mpf(str(interval.center))
else:
x0 = mpc(*map(str, interval.center))
try:
root = findroot(func, x0)
except ValueError:
interval = interval.refine()
refined = True
continue
else:
if refined:
self._set_interval(interval)
break
finally:
mp.prec = _prec
return Float._new(root.real._mpf_, prec) + I*Float._new(root.imag._mpf_, prec)
def _eval_evalf(self, prec):
"""Evaluate this complex root to the given precision. """
_prec, mp.prec = mp.prec, prec
try:
func = lambdify(self.poly.gen, self.expr)
interval = self._get_interval()
refined = False
while True:
if self.is_real:
x0 = mpf(str(interval.center))
else:
x0 = mpc(*map(str, interval.center))
try:
root = findroot(func, x0)
except ValueError:
interval = interval.refine()
refined = True
continue
else:
if refined:
self._set_interval(interval)
break
finally:
mp.prec = _prec
return Float._new(root.real._mpf_, prec) + I*Float._new(root.imag._mpf_, prec)
def _eval_evalf(self, prec):
"""Evaluate this complex root to the given precision. """
with workprec(prec):
g = self.poly.gen
if not g.is_Symbol:
d = Dummy('x')
func = lambdify(d, self.expr.subs(g, d))
else:
func = lambdify(g, self.expr)
interval = self._get_interval()
if not self.is_real:
# For complex intervals, we need to keep refining until the
# imaginary interval is disjunct with other roots, that is,
# until both ends get refined.
ay = interval.ay
by = interval.by
while interval.ay == ay or interval.by == by:
interval = interval.refine()
while True:
if self.is_real:
x0 = mpf(str(interval.center))
else:
x0 = mpc(*map(str, interval.center))
try:
root = findroot(func, x0, verify=False)
# If the (real or complex) root is not in the 'interval',
# then keep refining the interval. This happens if findroot
# accidentally finds a different root outside of this
# interval because our initial estimate 'x0' was not close
# enough.
if self.is_real:
a = mpf(str(interval.a))
b = mpf(str(interval.b))
if a == b:
root = a
break
if not (a < root < b):
raise ValueError("Root not in the interval.")
else:
ax = mpf(str(interval.ax))
bx = mpf(str(interval.bx))
ay = mpf(str(interval.ay))
by = mpf(str(interval.by))
if ax == bx and ay == by:
root = ax + S.ImaginaryUnit * by
break
if not (ax < root.real < bx and ay < root.imag < by):
raise ValueError("Root not in the interval.")
except ValueError:
interval = interval.refine()
continue
else:
break
return Float._new(root.real._mpf_,
prec) + I * Float._new(root.imag._mpf_, prec)
def _eval_evalf(self, prec):
"""Evaluate this complex root to the given precision. """
_prec, mp.prec = mp.prec, prec
try:
func = lambdify(self.poly.gen, self.expr)
interval = self._get_interval()
if not self.is_real:
# For complex intervals, we need to keep refining until the
# imaginary interval is disjunct with other roots, that is,
# until both ends get refined.
ay = interval.ay
by = interval.by
while interval.ay == ay or interval.by == by:
interval = interval.refine()
while True:
if self.is_real:
x0 = mpf(str(interval.center))
else:
x0 = mpc(*map(str, interval.center))
try:
root = findroot(func, x0)
# If the (real or complex) root is not in the 'interval',
# then keep refining the interval. This happens if findroot
# accidentally finds a different root outside of this
# interval because our initial estimate 'x0' was not close
# enough.
if self.is_real:
a = mpf(str(interval.a))
b = mpf(str(interval.b))
# This is needed due to the bug #3364:
a, b = min(a, b), max(a, b)
if not (a < root < b):
raise ValueError("Root not in the interval.")
else:
ax = mpf(str(interval.ax))
bx = mpf(str(interval.bx))
ay = mpf(str(interval.ay))
by = mpf(str(interval.by))
# This is needed due to the bug #3364:
ax, bx = min(ax, bx), max(ax, bx)
ay, by = min(ay, by), max(ay, by)
if not (ax < root.real < bx and ay < root.imag < by):
raise ValueError("Root not in the interval.")
except ValueError:
interval = interval.refine()
continue
else:
break
finally:
mp.prec = _prec
return Float._new(root.real._mpf_,
prec) + I * Float._new(root.imag._mpf_, prec)
def _eval_evalf(self, prec):
"""Evaluate this complex root to the given precision. """
with workprec(prec):
g = self.poly.gen
if not g.is_Symbol:
d = Dummy('x')
func = lambdify(d, self.expr.subs(g, d))
else:
func = lambdify(g, self.expr)
interval = self._get_interval()
if not self.is_real:
# For complex intervals, we need to keep refining until the
# imaginary interval is disjunct with other roots, that is,
# until both ends get refined.
ay = interval.ay
by = interval.by
while interval.ay == ay or interval.by == by:
interval = interval.refine()
while True:
if self.is_real:
x0 = mpf(str(interval.center))
else:
x0 = mpc(*map(str, interval.center))
try:
root = findroot(func, x0, verify=False)
# If the (real or complex) root is not in the 'interval',
# then keep refining the interval. This happens if findroot
# accidentally finds a different root outside of this
# interval because our initial estimate 'x0' was not close
# enough.
if self.is_real:
a = mpf(str(interval.a))
b = mpf(str(interval.b))
if a == b:
root = a
break
if not (a < root < b):
raise ValueError("Root not in the interval.")
else:
ax = mpf(str(interval.ax))
bx = mpf(str(interval.bx))
ay = mpf(str(interval.ay))
by = mpf(str(interval.by))
if ax == bx and ay == by:
root = ax + S.ImaginaryUnit*by
break
if not (ax < root.real < bx and ay < root.imag < by):
raise ValueError("Root not in the interval.")
except ValueError:
interval = interval.refine()
continue
else:
break
return Float._new(root.real._mpf_, prec) + I*Float._new(root.imag._mpf_, prec)
def _eval_evalf(self, prec):
"""Evaluate this complex root to the given precision. """
_prec, mp.prec = mp.prec, prec
try:
func = lambdify(self.poly.gen, self.expr)
interval = self._get_interval()
if not self.is_real:
# For complex intervals, we need to keep refining until the
# imaginary interval is disjunct with other roots, that is,
# until both ends get refined.
ay = interval.ay
by = interval.by
while interval.ay == ay or interval.by == by:
interval = interval.refine()
while True:
if self.is_real:
x0 = mpf(str(interval.center))
else:
x0 = mpc(*map(str, interval.center))
try:
root = findroot(func, x0)
# If the (real or complex) root is not in the 'interval',
# then keep refining the interval. This happens if findroot
# accidentally finds a different root outside of this
# interval because our initial estimate 'x0' was not close
# enough.
if self.is_real:
a = mpf(str(interval.a))
b = mpf(str(interval.b))
# This is needed due to the bug #3364:
a, b = min(a, b), max(a, b)
if not (a < root < b):
raise ValueError("Root not in the interval.")
else:
ax = mpf(str(interval.ax))
bx = mpf(str(interval.bx))
ay = mpf(str(interval.ay))
by = mpf(str(interval.by))
# This is needed due to the bug #3364:
ax, bx = min(ax, bx), max(ax, bx)
ay, by = min(ay, by), max(ay, by)
if not (ax < root.real < bx and ay < root.imag < by):
raise ValueError("Root not in the interval.")
except ValueError:
interval = interval.refine()
continue
else:
break
finally:
mp.prec = _prec
return Float._new(root.real._mpf_, prec) + I*Float._new(root.imag._mpf_, prec)
def critical_par(par="L1", p=p, extra_par={}):
old_p = p.copy()
p.update(extra_par)
if par != "r":
g = lambda x: G(0, p=p, extra_par={par: x}) - p["r"]
else:
g = lambda x: G(0, p=p, extra_par={par: x}) - x
result = mp.findroot(g, p[par], solver="secant")
p.update(old_p)
return result
def search_extreme_points(list_a):
def f(x):
return d_polynomial(x, list_a) - sm.cos(x);
def df(x):
return dd_polynomial(x, list_a) + sm.sin(x);
check_points = numpy.linspace(0.0, sm.pi, 100)
sign_reverse_section = \
[p for p in zip(check_points, check_points[1:]) if f(p[0])*f(p[1]) <= 0.0]
return [sm.findroot(f, x, df=df, tol=1.0e-20) for x,_ in sign_reverse_section]
def search_extreme_points(list_a):
def f(x):
return d_polynomial(x, list_a) - sm.cos(x)
def df(x):
return dd_polynomial(x, list_a) + sm.sin(x)
check_points = numpy.linspace(0.0, sm.pi, 100)
sign_reverse_section = \
[p for p in zip(check_points, check_points[1:]) if f(p[0])*f(p[1]) <= 0.0]
return [
sm.findroot(f, x, df=df, tol=1.0e-20) for x, _ in sign_reverse_section
]
def solver(f, x):
if method == "sympy":
# findroot(solver="newton") or findroot(solver="secant") can't find
# the root within the given tolerance. So we use solver="muller",
# which converges towards complex roots (even for real starting
# points), and so we need to chop all complex parts (that are small
# anyway). Also we need to set the tolerance, as it sometimes fail
# without it.
def f_real(x):
return f(complex(x).real)
root = findroot(f_real, x, solver="muller", tol=1e-9)
root = complex(root).real
elif method == "scipy":
root = newton(f, x)
else:
raise NotImplementedError("Unknown method.")
return root
def improve_mu_m(self,
beam_type,
mode,
decimal_precision=DEFAULT_DECIMAL_PRECISION,
**kwargs):
f = self._get_f(beam_type, decimal_precision)
with mpmath.workdps(decimal_precision):
# If not converted to `sympy.Float` precision will be lost after the
# original `mpmath` context is restored
return Float(
mpmath.findroot(f=f,
x0=self.x0(beam_type, mode, decimal_precision),
solver=self.solver_name,
maxsteps=self.max_iterations,
verify=False,
**kwargs), decimal_precision)
def solver(f, x):
if method == "sympy":
# findroot(solver="newton") or findroot(solver="secant") can't find
# the root within the given tolerance. So we use solver="muller",
# which converges towards complex roots (even for real starting
# points), and so we need to chop all complex parts (that are small
# anyway). Also we need to set the tolerance, as it sometimes fail
# without it.
def f_real(x):
return f(complex(x).real)
root = findroot(f_real, x, solver="muller", tol=1e-9)
root = complex(root).real
elif method == "scipy":
root = newton(f, x)
else:
raise NotImplementedError("Unknown method.")
return root
def find_roots(p):
'''Return set of roots of polynomial *p*.
:param p: sympy polynomial
This uses the *nroots* method of the SymPy polynomial class to give
rough roots, and subsequently refines these roots to arbitrary
precision using mpmath.
Returns a sorted *set* of roots.
'''
x = sympy.var('x')
roots = set()
for x0 in p.nroots():
xi = mpmath.findroot(lambda z: p.eval(x, z), x0)
roots.add(xi)
return sorted(roots)
def find_roots(p):
'''Return set of roots of polynomial *p*.
:param p: sympy polynomial
This uses the *nroots* method of the SymPy polynomial class to give
rough roots, and subsequently refines these roots to arbitrary
precision using mpmath.
Returns a sorted *set* of roots.
'''
x = sympy.var('x')
roots = set()
for x0 in p.nroots():
xi = mpmath.findroot(lambda z: p.eval(x, z), x0)
roots.add(xi)
return sorted(roots)
def _eval_evalf(self, prec):
"""Evaluate this complex root to the given precision. """
_prec, mp.prec = mp.prec, prec
try:
func = lambdify(self.poly.gen, self.expr)
interval, refined = self._get_interval(), False
while True:
if self.is_real:
x0 = mpf(str(interval.center))
else:
re, im = interval.center
re = mpf(str(re))
im = mpf(str(im))
x0 = mpc(re, im)
try:
root = findroot(func, x0)
except ValueError:
interval = interval.refine()
refined = True
continue
else:
if refined:
self._set_interval(interval)
if self.is_conjugate:
root = root.conjugate()
break
finally:
mp.prec = _prec
return Real._new(root.real._mpf_,
prec) + I * Real._new(root.imag._mpf_, prec)
def _eval_evalf(self, prec):
"""Evaluate this complex root to the given precision. """
_prec, mp.prec = mp.prec, prec
try:
func = lambdify(self.poly.gen, self.expr)
interval, refined = self._get_interval(), False
while True:
if self.is_real:
x0 = mpf(str(interval.center))
else:
re, im = interval.center
re = mpf(str(re))
im = mpf(str(im))
x0 = mpc(re, im)
try:
root = findroot(func, x0)
except ValueError:
interval = interval.refine()
refined = True
continue
else:
if refined:
self._set_interval(interval)
if self.is_conjugate:
root = root.conjugate()
break
finally:
mp.prec = _prec
return Real._new(root.real._mpf_, prec) + I*Real._new(root.imag._mpf_, prec)
def nsolve(*args, **kwargs):
"""
Solve a nonlinear equation system numerically.
nsolve(f, [args,] x0, modules=['mpmath'], **kwargs)
f is a vector function of symbolic expressions representing the system.
args are the variables. If there is only one variable, this argument can be
omitted.
x0 is a starting vector close to a solution.
Use the modules keyword to specify which modules should be used to evaluate
the function and the Jacobian matrix. Make sure to use a module that
supports matrices. For more information on the syntax, please see the
docstring of lambdify.
Overdetermined systems are supported.
>>> from sympy import Symbol, nsolve
>>> import sympy
>>> sympy.mpmath.mp.dps = 15
>>> x1 = Symbol('x1')
>>> x2 = Symbol('x2')
>>> f1 = 3 * x1**2 - 2 * x2**2 - 1
>>> f2 = x1**2 - 2 * x1 + x2**2 + 2 * x2 - 8
>>> print nsolve((f1, f2), (x1, x2), (-1, 1))
[-1.19287309935246]
[ 1.27844411169911]
For one-dimensional functions the syntax is simplified:
>>> from sympy import sin, nsolve
>>> from sympy.abc import x
>>> nsolve(sin(x), x, 2)
3.14159265358979
>>> nsolve(sin(x), 2)
3.14159265358979
mpmath.findroot is used, you can find there more extensive documentation,
especially concerning keyword parameters and available solvers.
"""
# interpret arguments
if len(args) == 3:
f = args[0]
fargs = args[1]
x0 = args[2]
elif len(args) == 2:
f = args[0]
fargs = None
x0 = args[1]
elif len(args) < 2:
raise TypeError("nsolve expected at least 2 arguments, got %i" % len(args))
else:
raise TypeError("nsolve expected at most 3 arguments, got %i" % len(args))
modules = kwargs.get("modules", ["mpmath"])
if isinstance(f, (list, tuple)):
f = Matrix(f).T
if not isinstance(f, Matrix):
# assume it's a sympy expression
if isinstance(f, Equality):
f = f.lhs - f.rhs
f = f.evalf()
atoms = f.atoms(Symbol)
if fargs is None:
fargs = atoms.copy().pop()
if not (len(atoms) == 1 and (fargs in atoms or fargs[0] in atoms)):
raise ValueError("expected a one-dimensional and numerical function")
# the function is much better behaved if there is no denominator
f = f.as_numer_denom()[0]
f = lambdify(fargs, f, modules)
return findroot(f, x0, **kwargs)
if len(fargs) > f.cols:
raise NotImplementedError("need at least as many equations as variables")
verbose = kwargs.get("verbose", False)
if verbose:
print "f(x):"
print f
# derive Jacobian
J = f.jacobian(fargs)
if verbose:
print "J(x):"
print J
# create functions
f = lambdify(fargs, f.T, modules)
J = lambdify(fargs, J, modules)
# solve the system numerically
x = findroot(f, x0, J=J, **kwargs)
return x
def nsolve(*args, **kwargs):
"""
Solve a nonlinear equation system numerically.
nsolve(f, [args,] x0, modules=['mpmath'], **kwargs)
f is a vector function of symbolic expressions representing the system.
args are the variables. If there is only one variable, this argument can be
omitted.
x0 is a starting vector close to a solution.
Use the modules keyword to specify which modules should be used to evaluate
the function and the Jacobian matrix. Make sure to use a module that
supports matrices. For more information on the syntax, please see the
docstring of lambdify.
Overdetermined systems are supported.
>>> from sympy import Symbol, nsolve
>>> import sympy
>>> sympy.mpmath.mp.dps = 15
>>> x1 = Symbol('x1')
>>> x2 = Symbol('x2')
>>> f1 = 3 * x1**2 - 2 * x2**2 - 1
>>> f2 = x1**2 - 2 * x1 + x2**2 + 2 * x2 - 8
>>> print nsolve((f1, f2), (x1, x2), (-1, 1))
[-1.19287309935246]
[ 1.27844411169911]
For one-dimensional functions the syntax is simplified:
>>> from sympy import sin, nsolve
>>> from sympy.abc import x
>>> nsolve(sin(x), x, 2)
3.14159265358979
>>> nsolve(sin(x), 2)
3.14159265358979
mpmath.findroot is used, you can find there more extensive documentation,
especially concerning keyword parameters and available solvers.
"""
# interpret arguments
if len(args) == 3:
f = args[0]
fargs = args[1]
x0 = args[2]
elif len(args) == 2:
f = args[0]
fargs = None
x0 = args[1]
elif len(args) < 2:
raise TypeError('nsolve expected at least 2 arguments, got %i' %
len(args))
else:
raise TypeError('nsolve expected at most 3 arguments, got %i' %
len(args))
modules = kwargs.get('modules', ['mpmath'])
if isinstance(f, (list, tuple)):
f = Matrix(f).T
if not isinstance(f, Matrix):
# assume it's a sympy expression
if isinstance(f, Equality):
f = f.lhs - f.rhs
f = f.evalf()
atoms = f.atoms(Symbol)
if fargs is None:
fargs = atoms.copy().pop()
if not (len(atoms) == 1 and (fargs in atoms or fargs[0] in atoms)):
raise ValueError(
'expected a one-dimensional and numerical function')
# the function is much better behaved if there is no denominator
f = f.as_numer_denom()[0]
f = lambdify(fargs, f, modules)
return findroot(f, x0, **kwargs)
if len(fargs) > f.cols:
raise NotImplementedError(
'need at least as many equations as variables')
verbose = kwargs.get('verbose', False)
if verbose:
print 'f(x):'
print f
# derive Jacobian
J = f.jacobian(fargs)
if verbose:
print 'J(x):'
print J
# create functions
f = lambdify(fargs, f.T, modules)
J = lambdify(fargs, J, modules)
# solve the system numerically
x = findroot(f, x0, J=J, **kwargs)
return x
from sympy import Symbol, ln, latex, diff, pretty_print
from sympy.mpmath import findroot
# p4
x = Symbol('x')
g = (1 + x) * ln(1 + x)
R = (x ** 2) / (2 * (1 + x / 3))
form = g - x - R
diff_1 = diff(form, x, 1)
diff_2 = diff(form, x, 2)
def diff_func(x):
return 2*x**2/(3*(2*x/3 + 2)**2) - 2*x/(2*x/3 + 2) + ln(x + 1)
findroot(diff_func, 0)
print('d=', sm.nstr(d, 17))
# -2*s0*s1*s3*x**3 + s0*s2*x + s1**2*s3*x**4 + x**2*(s0**2*s3 - s1*s2)
def f(s0,s1,s2,s3):
return s0*s2 - list_a[1], \
s0**2*s3 - s1*s2 - list_a[2], \
-2*s0*s1*s3 - list_a[3], \
s1**2*s3 - list_a[4]
print()
print('Newton method calculating...', end='')
initilal = (1.2732395447351627, 0.40528473456935109, 0.77633023248007499, 0.22308510060189463);
list_s = sm.findroot(
f,
initilal,
method='newton',
maxsteps=10000,
tol=1.0e-25)
print(' OK')
for k,s in enumerate(list_s):
print('s[' + str(k) + ']=', sm.nstr(s, 17))
#
#Remez algorithm calculating... OK
#a[0]= 0.0
#a[1]= 0.9897151132173856
#a[2]= 0.044771099390202579
#a[3]= -0.22906038058222875
#a[4]= 0.036456091836172492
#d= -0.00073239476651250248
print('d=', sm.nstr(d, 17))
# -2*s0*s1*s3*x**3 + s0*s2*x + s1**2*s3*x**4 + x**2*(s0**2*s3 - s1*s2)
def f(s0, s1, s2, s3):
return s0*s2 - list_a[1], \
s0**2*s3 - s1*s2 - list_a[2], \
-2*s0*s1*s3 - list_a[3], \
s1**2*s3 - list_a[4]
print()
print('Newton method calculating...', end='')
initilal = (1.2732395447351627, 0.40528473456935109, 0.77633023248007499,
0.22308510060189463)
list_s = sm.findroot(f,
initilal,
method='newton',
maxsteps=10000,
tol=1.0e-25)
print(' OK')
for k, s in enumerate(list_s):
print('s[' + str(k) + ']=', sm.nstr(s, 17))
#
#Remez algorithm calculating... OK
#a[0]= 0.0
#a[1]= 0.9897151132173856
#a[2]= 0.044771099390202579
#a[3]= -0.22906038058222875
#a[4]= 0.036456091836172492
#d= -0.00073239476651250248
f = simplify(pQ.pos_from(pP) & N.z)
print("f = {}\n".format(msprint(f)))
# calculate the derivative of f for use with newton-raphson
df = simplify(f.diff(theta))
print("df/dθ = {}\n".format(msprint(df)))
# constraint function for zero steer/lean configuration and
# using the benchmark parameters
f0 = lambdify(theta, f.subs({phi: 0, delta: 0}).subs(benchmark_parameters))
df0 = lambdify(theta, df.subs({phi: 0, delta: 0}).subs(benchmark_parameters))
print("verifying constraint equations are correct")
print("for zero steer/lean, pitch should be pi/10")
findroot(f0, 0.3, solver="newton", tol=1e-8, verbose=True, df=df0)
c_sym = [Symbol('lean'), Symbol('pitch'), Symbol('steer')]
c_sym_dict = dict(zip([phi, theta, delta], c_sym))
fc = ccode(f.subs(c_sym_dict))
dfc = ccode(df.subs(c_sym_dict))
cs_math = {
'cos': 'Math.Cos',
'sin': 'Math.Sin',
'pow': 'Math.Pow',
'sqrt': 'Math.Sqrt'
}
fcs = fc
