def wronskian(functions, var, method='bareis'):
"""
Compute Wronskian for [] of functions
::
| f1 f2 ... fn |
| f1' f2' ... fn' |
| . . . . |
W(f1, ..., fn) = | . . . . |
| . . . . |
| (n) (n) (n) |
| D (f1) D (f2) ... D (fn) |
see: http://en.wikipedia.org/wiki/Wronskian
See Also
========
sympy.matrices.mutable.Matrix.jacobian
hessian
"""
from dense import Matrix
for index in range(0, len(functions)):
functions[index] = sympify(functions[index])
n = len(functions)
if n == 0:
return 1
W = Matrix(n, n, lambda i, j: functions[i].diff(var, j))
return W.det(method)
def ones(r, c=None):
"""Returns a matrix of ones with ``r`` rows and ``c`` columns;
if ``c`` is omitted a square matrix will be returned.
See Also
========
zeros
eye
diag
"""
from dense import Matrix
if is_sequence(r):
SymPyDeprecationWarning(
feature="The syntax ones([%i, %i])" % tuple(r),
useinstead="ones(%i, %i)." % tuple(r),
issue=3381,
deprecated_since_version="0.7.2",
).warn()
r, c = r
else:
c = r if c is None else c
r = as_int(r)
c = as_int(c)
return Matrix(r, c, [S.One] * r * c)
def __eq__(self, other):
try:
if self.shape != other.shape:
return False
if isinstance(other, Matrix):
return self._mat == other._mat
elif isinstance(other, MatrixBase):
return self._mat == Matrix(other)._mat
except AttributeError:
return False
def _force_mutable(x):
"""Return a matrix as a Matrix, otherwise return x."""
if getattr(x, 'is_Matrix', False):
return x.as_mutable()
elif isinstance(x, Basic):
return x
elif hasattr(x, '__array__'):
a = x.__array__()
if len(a.shape) == 0:
return sympify(a)
return Matrix(x)
return x
def as_mutable(self):
"""Returns a mutable version of this matrix
Examples
========
>>> from sympy import ImmutableMatrix
>>> X = ImmutableMatrix([[1, 2], [3, 4]])
>>> Y = X.as_mutable()
>>> Y[1, 1] = 5 # Can set values in Y
>>> Y
[1, 2]
[3, 5]
"""
return Matrix(self)
def __init__(self, *args):
if len(args) == 1 and isinstance(args[0], SparseMatrix):
self.rows = args[0].rows
self.cols = args[0].cols
self._smat = dict(args[0]._smat)
return
self._smat = {}
if len(args) == 3:
self.rows = as_int(args[0])
self.cols = as_int(args[1])
if callable(args[2]):
op = args[2]
for i in range(self.rows):
for j in range(self.cols):
value = sympify(op(i, j))
if value:
self._smat[(i, j)] = value
elif isinstance(args[2], (dict, Dict)):
# manual copy, copy.deepcopy() doesn't work
for key in args[2].keys():
v = args[2][key]
if v:
self._smat[key] = v
elif is_sequence(args[2]):
if len(args[2]) != self.rows*self.cols:
raise ValueError(
'List length (%s) != rows*columns (%s)' %
(len(args[2]), self.rows*self.cols))
flat_list = args[2]
for i in range(self.rows):
for j in range(self.cols):
value = sympify(flat_list[i*self.cols + j])
if value:
self._smat[(i, j)] = value
else:
# handle full matrix forms with _handle_creation_inputs
r, c, _list = Matrix._handle_creation_inputs(*args)
self.rows = r
self.cols = c
for i in range(self.rows):
for j in range(self.cols):
value = _list[self.cols*i + j]
if value:
self._smat[(i, j)] = value
def __init__(self, *args):
if len(args) == 1 and isinstance(args[0], SparseMatrix):
self.rows = args[0].rows
self.cols = args[0].cols
self._smat = dict(args[0]._smat)
return
self._smat = {}
if len(args) == 3:
self.rows = as_int(args[0])
self.cols = as_int(args[1])
if callable(args[2]):
op = args[2]
for i in range(self.rows):
for j in range(self.cols):
value = self._sympify(op(i, j))
if value:
self._smat[(i, j)] = value
elif isinstance(args[2], (dict, Dict)):
# manual copy, copy.deepcopy() doesn't work
for key in args[2].keys():
v = args[2][key]
if v:
self._smat[key] = v
elif is_sequence(args[2]):
if len(args[2]) != self.rows*self.cols:
raise ValueError(
'List length (%s) != rows*columns (%s)' %
(len(args[2]), self.rows*self.cols))
flat_list = args[2]
for i in range(self.rows):
for j in range(self.cols):
value = self._sympify(flat_list[i*self.cols + j])
if value:
self._smat[(i, j)] = value
else:
# handle full matrix forms with _handle_creation_inputs
r, c, _list = Matrix._handle_creation_inputs(*args)
self.rows = r
self.cols = c
for i in range(self.rows):
for j in range(self.cols):
value = _list[self.cols*i + j]
if value:
self._smat[(i, j)] = value
def casoratian(seqs, n, zero=True):
"""Given linear difference operator L of order 'k' and homogeneous
equation Ly = 0 we want to compute kernel of L, which is a set
of 'k' sequences: a(n), b(n), ... z(n).
Solutions of L are linearly independent iff their Casoratian,
denoted as C(a, b, ..., z), do not vanish for n = 0.
Casoratian is defined by k x k determinant::
+ a(n) b(n) . . . z(n) +
| a(n+1) b(n+1) . . . z(n+1) |
| . . . . |
| . . . . |
| . . . . |
+ a(n+k-1) b(n+k-1) . . . z(n+k-1) +
It proves very useful in rsolve_hyper() where it is applied
to a generating set of a recurrence to factor out linearly
dependent solutions and return a basis:
>>> from sympy import Symbol, casoratian, factorial
>>> n = Symbol('n', integer=True)
Exponential and factorial are linearly independent:
>>> casoratian([2**n, factorial(n)], n) != 0
True
"""
from dense import Matrix
seqs = map(sympify, seqs)
if not zero:
f = lambda i, j: seqs[j].subs(n, n + i)
else:
f = lambda i, j: seqs[j].subs(n, i)
k = len(seqs)
return Matrix(k, k, f).det()
def rot_axis1(theta):
"""Returns a rotation matrix for a rotation of theta (in radians) about
the 1-axis.
Examples
========
>>> from sympy import pi
>>> from sympy.matrices import rot_axis1
A rotation of pi/3 (60 degrees):
>>> theta = pi/3
>>> rot_axis1(theta)
Matrix([
[1, 0, 0],
[0, 1/2, sqrt(3)/2],
[0, -sqrt(3)/2, 1/2]])
If we rotate by pi/2 (90 degrees):
>>> rot_axis1(pi/2)
Matrix([
[1, 0, 0],
[0, 0, 1],
[0, -1, 0]])
See Also
========
rot_axis2: Returns a rotation matrix for a rotation of theta (in radians)
about the 2-axis
rot_axis3: Returns a rotation matrix for a rotation of theta (in radians)
about the 3-axis
"""
ct = cos(theta)
st = sin(theta)
lil = ((1, 0, 0),
(0, ct, st),
(0, -st, ct))
return Matrix(lil)
def rot_axis2(theta):
"""Returns a rotation matrix for a rotation of theta (in radians) about
the 2-axis.
Examples
--------
>>> from sympy import pi
>>> from sympy.matrices import rot_axis2
A rotation of pi/3 (60 degrees):
>>> theta = pi/3
>>> rot_axis2(theta)
[ 1/2, 0, -sqrt(3)/2]
[ 0, 1, 0]
[sqrt(3)/2, 0, 1/2]
If we rotate by pi/2 (90 degrees):
>>> rot_axis2(pi/2)
[0, 0, -1]
[0, 1, 0]
[1, 0, 0]
See Also
========
rot_axis1: Returns a rotation matrix for a rotation of theta (in radians)
about the 1-axis
rot_axis3: Returns a rotation matrix for a rotation of theta (in radians)
about the 3-axis
"""
ct = cos(theta)
st = sin(theta)
lil = ((ct, 0, -st),
(0, 1, 0),
(st, 0, ct))
return Matrix(lil)
def copyin_list(self, key, value):
"""Copy in elements from a list.
Parameters
==========
key : slice
The section of this matrix to replace.
value : iterable
The iterable to copy values from.
Examples
========
>>> from sympy.matrices import eye
>>> I = eye(3)
>>> I[:2, 0] = [1, 2] # col
>>> I
Matrix([
[1, 0, 0],
[2, 1, 0],
[0, 0, 1]])
>>> I[1, :2] = [[3, 4]]
>>> I
Matrix([
[1, 0, 0],
[3, 4, 0],
[0, 0, 1]])
See Also
========
copyin_matrix
"""
if not is_sequence(value):
raise TypeError("`value` must be an ordered iterable, not %s." % type(value))
return self.copyin_matrix(key, Matrix(value))
def zeros(r, c=None, cls=None):
"""Returns a matrix of zeros with ``r`` rows and ``c`` columns;
if ``c`` is omitted a square matrix will be returned.
See Also
========
ones
eye
diag
"""
if cls is None:
from dense import Matrix as cls
if is_sequence(r):
SymPyDeprecationWarning(
feature="The syntax zeros([%i, %i])" % tuple(r),
useinstead="zeros(%i, %i)." % tuple(r),
issue=3381, deprecated_since_version="0.7.2",
).warn()
r, c = r
else:
c = r if c is None else c
r, c = [int(i) for i in [r, c]]
return cls.zeros(r, c)
def randMatrix(r, c=None, min=0, max=99, seed=None, symmetric=False, percent=100):
"""Create random matrix with dimensions ``r`` x ``c``. If ``c`` is omitted
the matrix will be square. If ``symmetric`` is True the matrix must be
square. If ``percent`` is less than 100 then only approximately the given
percentage of elements will be non-zero.
Examples
========
>>> from sympy.matrices import randMatrix
>>> randMatrix(3) # doctest:+SKIP
[25, 45, 27]
[44, 54, 9]
[23, 96, 46]
>>> randMatrix(3, 2) # doctest:+SKIP
[87, 29]
[23, 37]
[90, 26]
>>> randMatrix(3, 3, 0, 2) # doctest:+SKIP
[0, 2, 0]
[2, 0, 1]
[0, 0, 1]
>>> randMatrix(3, symmetric=True) # doctest:+SKIP
[85, 26, 29]
[26, 71, 43]
[29, 43, 57]
>>> A = randMatrix(3, seed=1)
>>> B = randMatrix(3, seed=2)
>>> A == B # doctest:+SKIP
False
>>> A == randMatrix(3, seed=1)
True
>>> randMatrix(3, symmetric=True, percent=50) # doctest:+SKIP
[0, 68, 43]
[0, 68, 0]
[0, 91, 34]
"""
if c is None:
c = r
if seed is None:
prng = random.Random() # use system time
else:
prng = random.Random(seed)
if symmetric and r != c:
raise ValueError(
'For symmetric matrices, r must equal c, but %i != %i' % (r, c))
if not symmetric:
m = Matrix._new(r, c, lambda i, j: prng.randint(min, max))
else:
m = zeros(r)
for i in range(r):
for j in range(i, r):
m[i, j] = prng.randint(min, max)
for i in range(r):
for j in range(i):
m[i, j] = m[j, i]
if percent == 100:
return m
else:
z = int(r*c*percent // 100)
m._mat[:z] = [S.Zero]*z
random.shuffle(m._mat)
return m
def randMatrix(r, c=None, min=0, max=99, seed=None, symmetric=False, percent=100):
"""Create random matrix with dimensions ``r`` x ``c``. If ``c`` is omitted
the matrix will be square. If ``symmetric`` is True the matrix must be
square. If ``percent`` is less than 100 then only approximately the given
percentage of elements will be non-zero.
Examples
========
>>> from sympy.matrices import randMatrix
>>> randMatrix(3) # doctest:+SKIP
[25, 45, 27]
[44, 54, 9]
[23, 96, 46]
>>> randMatrix(3, 2) # doctest:+SKIP
[87, 29]
[23, 37]
[90, 26]
>>> randMatrix(3, 3, 0, 2) # doctest:+SKIP
[0, 2, 0]
[2, 0, 1]
[0, 0, 1]
>>> randMatrix(3, symmetric=True) # doctest:+SKIP
[85, 26, 29]
[26, 71, 43]
[29, 43, 57]
>>> A = randMatrix(3, seed=1)
>>> B = randMatrix(3, seed=2)
>>> A == B # doctest:+SKIP
False
>>> A == randMatrix(3, seed=1)
True
>>> randMatrix(3, symmetric=True, percent=50) # doctest:+SKIP
[0, 68, 43]
[0, 68, 0]
[0, 91, 34]
"""
if c is None:
c = r
if seed is None:
prng = random.Random() # use system time
else:
prng = random.Random(seed)
if symmetric and r != c:
raise ValueError(
'For symmetric matrices, r must equal c, but %i != %i' % (r, c))
if not symmetric:
m = Matrix._new(r, c, lambda i, j: prng.randint(min, max))
else:
m = zeros(r)
for i in range(r):
for j in range(i, r):
m[i, j] = prng.randint(min, max)
for i in range(r):
for j in range(i):
m[i, j] = m[j, i]
if percent == 100:
return m
else:
z = int(r*c*percent // 100)
m._mat[:z] = [S.Zero]*z
prng.shuffle(m._mat)
return m
def diag(*values, **kwargs):
"""Create a sparse, diagonal matrix from a list of diagonal values.
Notes
=====
When arguments are matrices they are fitted in resultant matrix.
The returned matrix is a mutable, dense matrix. To make it a different
type, send the desired class for keyword ``cls``.
Examples
========
>>> from sympy.matrices import diag, Matrix, ones
>>> diag(1, 2, 3)
Matrix([
[1, 0, 0],
[0, 2, 0],
[0, 0, 3]])
>>> diag(*[1, 2, 3])
Matrix([
[1, 0, 0],
[0, 2, 0],
[0, 0, 3]])
The diagonal elements can be matrices; diagonal filling will
continue on the diagonal from the last element of the matrix:
>>> from sympy.abc import x, y, z
>>> a = Matrix([x, y, z])
>>> b = Matrix([[1, 2], [3, 4]])
>>> c = Matrix([[5, 6]])
>>> diag(a, 7, b, c)
Matrix([
[x, 0, 0, 0, 0, 0],
[y, 0, 0, 0, 0, 0],
[z, 0, 0, 0, 0, 0],
[0, 7, 0, 0, 0, 0],
[0, 0, 1, 2, 0, 0],
[0, 0, 3, 4, 0, 0],
[0, 0, 0, 0, 5, 6]])
When diagonal elements are lists, they will be treated as arguments
to Matrix:
>>> diag([1, 2, 3], 4)
Matrix([
[1, 0],
[2, 0],
[3, 0],
[0, 4]])
>>> diag([[1, 2, 3]], 4)
Matrix([
[1, 2, 3, 0],
[0, 0, 0, 4]])
A given band off the diagonal can be made by padding with a
vertical or horizontal "kerning" vector:
>>> hpad = ones(0, 2)
>>> vpad = ones(2, 0)
>>> diag(vpad, 1, 2, 3, hpad) + diag(hpad, 4, 5, 6, vpad)
Matrix([
[0, 0, 4, 0, 0],
[0, 0, 0, 5, 0],
[1, 0, 0, 0, 6],
[0, 2, 0, 0, 0],
[0, 0, 3, 0, 0]])
The type is mutable by default but can be made immutable by setting
the ``mutable`` flag to False:
>>> type(diag(1))
<class 'sympy.matrices.dense.MutableDenseMatrix'>
>>> from sympy.matrices import ImmutableMatrix
>>> type(diag(1, cls=ImmutableMatrix))
<class 'sympy.matrices.immutable.ImmutableMatrix'>
See Also
========
eye
"""
from sparse import MutableSparseMatrix
cls = kwargs.pop('cls', None)
if cls is None:
from dense import Matrix as cls
if kwargs:
raise ValueError('unrecognized keyword%s: %s' % (
's' if len(kwargs) > 1 else '',
', '.join(kwargs.keys())))
rows = 0
cols = 0
values = list(values)
for i in range(len(values)):
m = values[i]
if isinstance(m, MatrixBase):
rows += m.rows
cols += m.cols
elif is_sequence(m):
m = values[i] = Matrix(m)
rows += m.rows
cols += m.cols
else:
rows += 1
cols += 1
res = MutableSparseMatrix.zeros(rows, cols)
i_row = 0
i_col = 0
for m in values:
if isinstance(m, MatrixBase):
res[i_row:i_row + m.rows, i_col:i_col + m.cols] = m
i_row += m.rows
i_col += m.cols
else:
res[i_row, i_col] = m
i_row += 1
i_col += 1
return cls._new(res)
def copyin_list(self, key, value):
if not is_sequence(value):
raise TypeError("`value` must be of type list or tuple.")
self.copyin_matrix(key, Matrix(value))