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- """
- Octave (and Matlab) code printer
- The `OctaveCodePrinter` converts SymPy expressions into Octave expressions.
- It uses a subset of the Octave language for Matlab compatibility.
- A complete code generator, which uses `octave_code` extensively, can be found
- in `sympy.utilities.codegen`. The `codegen` module can be used to generate
- complete source code files.
- """
- from typing import Any, Dict as tDict
- from sympy.core import Mul, Pow, S, Rational
- from sympy.core.mul import _keep_coeff
- from sympy.printing.codeprinter import CodePrinter
- from sympy.printing.precedence import precedence, PRECEDENCE
- from re import search
- # List of known functions. First, those that have the same name in
- # SymPy and Octave. This is almost certainly incomplete!
- known_fcns_src1 = ["sin", "cos", "tan", "cot", "sec", "csc",
- "asin", "acos", "acot", "atan", "atan2", "asec", "acsc",
- "sinh", "cosh", "tanh", "coth", "csch", "sech",
- "asinh", "acosh", "atanh", "acoth", "asech", "acsch",
- "erfc", "erfi", "erf", "erfinv", "erfcinv",
- "besseli", "besselj", "besselk", "bessely",
- "bernoulli", "beta", "euler", "exp", "factorial", "floor",
- "fresnelc", "fresnels", "gamma", "harmonic", "log",
- "polylog", "sign", "zeta", "legendre"]
- # These functions have different names ("SymPy": "Octave"), more
- # generally a mapping to (argument_conditions, octave_function).
- known_fcns_src2 = {
- "Abs": "abs",
- "arg": "angle", # arg/angle ok in Octave but only angle in Matlab
- "binomial": "bincoeff",
- "ceiling": "ceil",
- "chebyshevu": "chebyshevU",
- "chebyshevt": "chebyshevT",
- "Chi": "coshint",
- "Ci": "cosint",
- "conjugate": "conj",
- "DiracDelta": "dirac",
- "Heaviside": "heaviside",
- "im": "imag",
- "laguerre": "laguerreL",
- "LambertW": "lambertw",
- "li": "logint",
- "loggamma": "gammaln",
- "Max": "max",
- "Min": "min",
- "Mod": "mod",
- "polygamma": "psi",
- "re": "real",
- "RisingFactorial": "pochhammer",
- "Shi": "sinhint",
- "Si": "sinint",
- }
- class OctaveCodePrinter(CodePrinter):
- """
- A printer to convert expressions to strings of Octave/Matlab code.
- """
- printmethod = "_octave"
- language = "Octave"
- _operators = {
- 'and': '&',
- 'or': '|',
- 'not': '~',
- }
- _default_settings = {
- 'order': None,
- 'full_prec': 'auto',
- 'precision': 17,
- 'user_functions': {},
- 'human': True,
- 'allow_unknown_functions': False,
- 'contract': True,
- 'inline': True,
- } # type: tDict[str, Any]
- # Note: contract is for expressing tensors as loops (if True), or just
- # assignment (if False). FIXME: this should be looked a more carefully
- # for Octave.
- def __init__(self, settings={}):
- super().__init__(settings)
- self.known_functions = dict(zip(known_fcns_src1, known_fcns_src1))
- self.known_functions.update(dict(known_fcns_src2))
- userfuncs = settings.get('user_functions', {})
- self.known_functions.update(userfuncs)
- def _rate_index_position(self, p):
- return p*5
- def _get_statement(self, codestring):
- return "%s;" % codestring
- def _get_comment(self, text):
- return "% {}".format(text)
- def _declare_number_const(self, name, value):
- return "{} = {};".format(name, value)
- def _format_code(self, lines):
- return self.indent_code(lines)
- def _traverse_matrix_indices(self, mat):
- # Octave uses Fortran order (column-major)
- rows, cols = mat.shape
- return ((i, j) for j in range(cols) for i in range(rows))
- def _get_loop_opening_ending(self, indices):
- open_lines = []
- close_lines = []
- for i in indices:
- # Octave arrays start at 1 and end at dimension
- var, start, stop = map(self._print,
- [i.label, i.lower + 1, i.upper + 1])
- open_lines.append("for %s = %s:%s" % (var, start, stop))
- close_lines.append("end")
- return open_lines, close_lines
- def _print_Mul(self, expr):
- # print complex numbers nicely in Octave
- if (expr.is_number and expr.is_imaginary and
- (S.ImaginaryUnit*expr).is_Integer):
- return "%si" % self._print(-S.ImaginaryUnit*expr)
- # cribbed from str.py
- prec = precedence(expr)
- c, e = expr.as_coeff_Mul()
- if c < 0:
- expr = _keep_coeff(-c, e)
- sign = "-"
- else:
- sign = ""
- a = [] # items in the numerator
- b = [] # items that are in the denominator (if any)
- pow_paren = [] # Will collect all pow with more than one base element and exp = -1
- if self.order not in ('old', 'none'):
- args = expr.as_ordered_factors()
- else:
- # use make_args in case expr was something like -x -> x
- args = Mul.make_args(expr)
- # Gather args for numerator/denominator
- for item in args:
- if (item.is_commutative and item.is_Pow and item.exp.is_Rational
- and item.exp.is_negative):
- if item.exp != -1:
- b.append(Pow(item.base, -item.exp, evaluate=False))
- else:
- if len(item.args[0].args) != 1 and isinstance(item.base, Mul): # To avoid situations like #14160
- pow_paren.append(item)
- b.append(Pow(item.base, -item.exp))
- elif item.is_Rational and item is not S.Infinity:
- if item.p != 1:
- a.append(Rational(item.p))
- if item.q != 1:
- b.append(Rational(item.q))
- else:
- a.append(item)
- a = a or [S.One]
- a_str = [self.parenthesize(x, prec) for x in a]
- b_str = [self.parenthesize(x, prec) for x in b]
- # To parenthesize Pow with exp = -1 and having more than one Symbol
- for item in pow_paren:
- if item.base in b:
- b_str[b.index(item.base)] = "(%s)" % b_str[b.index(item.base)]
- # from here it differs from str.py to deal with "*" and ".*"
- def multjoin(a, a_str):
- # here we probably are assuming the constants will come first
- r = a_str[0]
- for i in range(1, len(a)):
- mulsym = '*' if a[i-1].is_number else '.*'
- r = r + mulsym + a_str[i]
- return r
- if not b:
- return sign + multjoin(a, a_str)
- elif len(b) == 1:
- divsym = '/' if b[0].is_number else './'
- return sign + multjoin(a, a_str) + divsym + b_str[0]
- else:
- divsym = '/' if all(bi.is_number for bi in b) else './'
- return (sign + multjoin(a, a_str) +
- divsym + "(%s)" % multjoin(b, b_str))
- def _print_Relational(self, expr):
- lhs_code = self._print(expr.lhs)
- rhs_code = self._print(expr.rhs)
- op = expr.rel_op
- return "{} {} {}".format(lhs_code, op, rhs_code)
- def _print_Pow(self, expr):
- powsymbol = '^' if all(x.is_number for x in expr.args) else '.^'
- PREC = precedence(expr)
- if expr.exp == S.Half:
- return "sqrt(%s)" % self._print(expr.base)
- if expr.is_commutative:
- if expr.exp == -S.Half:
- sym = '/' if expr.base.is_number else './'
- return "1" + sym + "sqrt(%s)" % self._print(expr.base)
- if expr.exp == -S.One:
- sym = '/' if expr.base.is_number else './'
- return "1" + sym + "%s" % self.parenthesize(expr.base, PREC)
- return '%s%s%s' % (self.parenthesize(expr.base, PREC), powsymbol,
- self.parenthesize(expr.exp, PREC))
- def _print_MatPow(self, expr):
- PREC = precedence(expr)
- return '%s^%s' % (self.parenthesize(expr.base, PREC),
- self.parenthesize(expr.exp, PREC))
- def _print_MatrixSolve(self, expr):
- PREC = precedence(expr)
- return "%s \\ %s" % (self.parenthesize(expr.matrix, PREC),
- self.parenthesize(expr.vector, PREC))
- def _print_Pi(self, expr):
- return 'pi'
- def _print_ImaginaryUnit(self, expr):
- return "1i"
- def _print_Exp1(self, expr):
- return "exp(1)"
- def _print_GoldenRatio(self, expr):
- # FIXME: how to do better, e.g., for octave_code(2*GoldenRatio)?
- #return self._print((1+sqrt(S(5)))/2)
- return "(1+sqrt(5))/2"
- def _print_Assignment(self, expr):
- from sympy.codegen.ast import Assignment
- from sympy.functions.elementary.piecewise import Piecewise
- from sympy.tensor.indexed import IndexedBase
- # Copied from codeprinter, but remove special MatrixSymbol treatment
- lhs = expr.lhs
- rhs = expr.rhs
- # We special case assignments that take multiple lines
- if not self._settings["inline"] and isinstance(expr.rhs, Piecewise):
- # Here we modify Piecewise so each expression is now
- # an Assignment, and then continue on the print.
- expressions = []
- conditions = []
- for (e, c) in rhs.args:
- expressions.append(Assignment(lhs, e))
- conditions.append(c)
- temp = Piecewise(*zip(expressions, conditions))
- return self._print(temp)
- if self._settings["contract"] and (lhs.has(IndexedBase) or
- rhs.has(IndexedBase)):
- # Here we check if there is looping to be done, and if so
- # print the required loops.
- return self._doprint_loops(rhs, lhs)
- else:
- lhs_code = self._print(lhs)
- rhs_code = self._print(rhs)
- return self._get_statement("%s = %s" % (lhs_code, rhs_code))
- def _print_Infinity(self, expr):
- return 'inf'
- def _print_NegativeInfinity(self, expr):
- return '-inf'
- def _print_NaN(self, expr):
- return 'NaN'
- def _print_list(self, expr):
- return '{' + ', '.join(self._print(a) for a in expr) + '}'
- _print_tuple = _print_list
- _print_Tuple = _print_list
- _print_List = _print_list
- def _print_BooleanTrue(self, expr):
- return "true"
- def _print_BooleanFalse(self, expr):
- return "false"
- def _print_bool(self, expr):
- return str(expr).lower()
- # Could generate quadrature code for definite Integrals?
- #_print_Integral = _print_not_supported
- def _print_MatrixBase(self, A):
- # Handle zero dimensions:
- if (A.rows, A.cols) == (0, 0):
- return '[]'
- elif S.Zero in A.shape:
- return 'zeros(%s, %s)' % (A.rows, A.cols)
- elif (A.rows, A.cols) == (1, 1):
- # Octave does not distinguish between scalars and 1x1 matrices
- return self._print(A[0, 0])
- return "[%s]" % "; ".join(" ".join([self._print(a) for a in A[r, :]])
- for r in range(A.rows))
- def _print_SparseRepMatrix(self, A):
- from sympy.matrices import Matrix
- L = A.col_list();
- # make row vectors of the indices and entries
- I = Matrix([[k[0] + 1 for k in L]])
- J = Matrix([[k[1] + 1 for k in L]])
- AIJ = Matrix([[k[2] for k in L]])
- return "sparse(%s, %s, %s, %s, %s)" % (self._print(I), self._print(J),
- self._print(AIJ), A.rows, A.cols)
- def _print_MatrixElement(self, expr):
- return self.parenthesize(expr.parent, PRECEDENCE["Atom"], strict=True) \
- + '(%s, %s)' % (expr.i + 1, expr.j + 1)
- def _print_MatrixSlice(self, expr):
- def strslice(x, lim):
- l = x[0] + 1
- h = x[1]
- step = x[2]
- lstr = self._print(l)
- hstr = 'end' if h == lim else self._print(h)
- if step == 1:
- if l == 1 and h == lim:
- return ':'
- if l == h:
- return lstr
- else:
- return lstr + ':' + hstr
- else:
- return ':'.join((lstr, self._print(step), hstr))
- return (self._print(expr.parent) + '(' +
- strslice(expr.rowslice, expr.parent.shape[0]) + ', ' +
- strslice(expr.colslice, expr.parent.shape[1]) + ')')
- def _print_Indexed(self, expr):
- inds = [ self._print(i) for i in expr.indices ]
- return "%s(%s)" % (self._print(expr.base.label), ", ".join(inds))
- def _print_Idx(self, expr):
- return self._print(expr.label)
- def _print_KroneckerDelta(self, expr):
- prec = PRECEDENCE["Pow"]
- return "double(%s == %s)" % tuple(self.parenthesize(x, prec)
- for x in expr.args)
- def _print_HadamardProduct(self, expr):
- return '.*'.join([self.parenthesize(arg, precedence(expr))
- for arg in expr.args])
- def _print_HadamardPower(self, expr):
- PREC = precedence(expr)
- return '.**'.join([
- self.parenthesize(expr.base, PREC),
- self.parenthesize(expr.exp, PREC)
- ])
- def _print_Identity(self, expr):
- shape = expr.shape
- if len(shape) == 2 and shape[0] == shape[1]:
- shape = [shape[0]]
- s = ", ".join(self._print(n) for n in shape)
- return "eye(" + s + ")"
- def _print_lowergamma(self, expr):
- # Octave implements regularized incomplete gamma function
- return "(gammainc({1}, {0}).*gamma({0}))".format(
- self._print(expr.args[0]), self._print(expr.args[1]))
- def _print_uppergamma(self, expr):
- return "(gammainc({1}, {0}, 'upper').*gamma({0}))".format(
- self._print(expr.args[0]), self._print(expr.args[1]))
- def _print_sinc(self, expr):
- #Note: Divide by pi because Octave implements normalized sinc function.
- return "sinc(%s)" % self._print(expr.args[0]/S.Pi)
- def _print_hankel1(self, expr):
- return "besselh(%s, 1, %s)" % (self._print(expr.order),
- self._print(expr.argument))
- def _print_hankel2(self, expr):
- return "besselh(%s, 2, %s)" % (self._print(expr.order),
- self._print(expr.argument))
- # Note: as of 2015, Octave doesn't have spherical Bessel functions
- def _print_jn(self, expr):
- from sympy.functions import sqrt, besselj
- x = expr.argument
- expr2 = sqrt(S.Pi/(2*x))*besselj(expr.order + S.Half, x)
- return self._print(expr2)
- def _print_yn(self, expr):
- from sympy.functions import sqrt, bessely
- x = expr.argument
- expr2 = sqrt(S.Pi/(2*x))*bessely(expr.order + S.Half, x)
- return self._print(expr2)
- def _print_airyai(self, expr):
- return "airy(0, %s)" % self._print(expr.args[0])
- def _print_airyaiprime(self, expr):
- return "airy(1, %s)" % self._print(expr.args[0])
- def _print_airybi(self, expr):
- return "airy(2, %s)" % self._print(expr.args[0])
- def _print_airybiprime(self, expr):
- return "airy(3, %s)" % self._print(expr.args[0])
- def _print_expint(self, expr):
- mu, x = expr.args
- if mu != 1:
- return self._print_not_supported(expr)
- return "expint(%s)" % self._print(x)
- def _one_or_two_reversed_args(self, expr):
- assert len(expr.args) <= 2
- return '{name}({args})'.format(
- name=self.known_functions[expr.__class__.__name__],
- args=", ".join([self._print(x) for x in reversed(expr.args)])
- )
- _print_DiracDelta = _print_LambertW = _one_or_two_reversed_args
- def _nested_binary_math_func(self, expr):
- return '{name}({arg1}, {arg2})'.format(
- name=self.known_functions[expr.__class__.__name__],
- arg1=self._print(expr.args[0]),
- arg2=self._print(expr.func(*expr.args[1:]))
- )
- _print_Max = _print_Min = _nested_binary_math_func
- def _print_Piecewise(self, expr):
- if expr.args[-1].cond != True:
- # We need the last conditional to be a True, otherwise the resulting
- # function may not return a result.
- raise ValueError("All Piecewise expressions must contain an "
- "(expr, True) statement to be used as a default "
- "condition. Without one, the generated "
- "expression may not evaluate to anything under "
- "some condition.")
- lines = []
- if self._settings["inline"]:
- # Express each (cond, expr) pair in a nested Horner form:
- # (condition) .* (expr) + (not cond) .* (<others>)
- # Expressions that result in multiple statements won't work here.
- ecpairs = ["({0}).*({1}) + (~({0})).*(".format
- (self._print(c), self._print(e))
- for e, c in expr.args[:-1]]
- elast = "%s" % self._print(expr.args[-1].expr)
- pw = " ...\n".join(ecpairs) + elast + ")"*len(ecpairs)
- # Note: current need these outer brackets for 2*pw. Would be
- # nicer to teach parenthesize() to do this for us when needed!
- return "(" + pw + ")"
- else:
- for i, (e, c) in enumerate(expr.args):
- if i == 0:
- lines.append("if (%s)" % self._print(c))
- elif i == len(expr.args) - 1 and c == True:
- lines.append("else")
- else:
- lines.append("elseif (%s)" % self._print(c))
- code0 = self._print(e)
- lines.append(code0)
- if i == len(expr.args) - 1:
- lines.append("end")
- return "\n".join(lines)
- def _print_zeta(self, expr):
- if len(expr.args) == 1:
- return "zeta(%s)" % self._print(expr.args[0])
- else:
- # Matlab two argument zeta is not equivalent to SymPy's
- return self._print_not_supported(expr)
- def indent_code(self, code):
- """Accepts a string of code or a list of code lines"""
- # code mostly copied from ccode
- if isinstance(code, str):
- code_lines = self.indent_code(code.splitlines(True))
- return ''.join(code_lines)
- tab = " "
- inc_regex = ('^function ', '^if ', '^elseif ', '^else$', '^for ')
- dec_regex = ('^end$', '^elseif ', '^else$')
- # pre-strip left-space from the code
- code = [ line.lstrip(' \t') for line in code ]
- increase = [ int(any(search(re, line) for re in inc_regex))
- for line in code ]
- decrease = [ int(any(search(re, line) for re in dec_regex))
- for line in code ]
- pretty = []
- level = 0
- for n, line in enumerate(code):
- if line in ('', '\n'):
- pretty.append(line)
- continue
- level -= decrease[n]
- pretty.append("%s%s" % (tab*level, line))
- level += increase[n]
- return pretty
- def octave_code(expr, assign_to=None, **settings):
- r"""Converts `expr` to a string of Octave (or Matlab) code.
- The string uses a subset of the Octave language for Matlab compatibility.
- Parameters
- ==========
- expr : Expr
- A SymPy expression to be converted.
- assign_to : optional
- When given, the argument is used as the name of the variable to which
- the expression is assigned. Can be a string, ``Symbol``,
- ``MatrixSymbol``, or ``Indexed`` type. This can be helpful for
- expressions that generate multi-line statements.
- precision : integer, optional
- The precision for numbers such as pi [default=16].
- user_functions : dict, optional
- A dictionary where keys are ``FunctionClass`` instances and values are
- their string representations. Alternatively, the dictionary value can
- be a list of tuples i.e. [(argument_test, cfunction_string)]. See
- below for examples.
- human : bool, optional
- If True, the result is a single string that may contain some constant
- declarations for the number symbols. If False, the same information is
- returned in a tuple of (symbols_to_declare, not_supported_functions,
- code_text). [default=True].
- contract: bool, optional
- If True, ``Indexed`` instances are assumed to obey tensor contraction
- rules and the corresponding nested loops over indices are generated.
- Setting contract=False will not generate loops, instead the user is
- responsible to provide values for the indices in the code.
- [default=True].
- inline: bool, optional
- If True, we try to create single-statement code instead of multiple
- statements. [default=True].
- Examples
- ========
- >>> from sympy import octave_code, symbols, sin, pi
- >>> x = symbols('x')
- >>> octave_code(sin(x).series(x).removeO())
- 'x.^5/120 - x.^3/6 + x'
- >>> from sympy import Rational, ceiling
- >>> x, y, tau = symbols("x, y, tau")
- >>> octave_code((2*tau)**Rational(7, 2))
- '8*sqrt(2)*tau.^(7/2)'
- Note that element-wise (Hadamard) operations are used by default between
- symbols. This is because its very common in Octave to write "vectorized"
- code. It is harmless if the values are scalars.
- >>> octave_code(sin(pi*x*y), assign_to="s")
- 's = sin(pi*x.*y);'
- If you need a matrix product "*" or matrix power "^", you can specify the
- symbol as a ``MatrixSymbol``.
- >>> from sympy import Symbol, MatrixSymbol
- >>> n = Symbol('n', integer=True, positive=True)
- >>> A = MatrixSymbol('A', n, n)
- >>> octave_code(3*pi*A**3)
- '(3*pi)*A^3'
- This class uses several rules to decide which symbol to use a product.
- Pure numbers use "*", Symbols use ".*" and MatrixSymbols use "*".
- A HadamardProduct can be used to specify componentwise multiplication ".*"
- of two MatrixSymbols. There is currently there is no easy way to specify
- scalar symbols, so sometimes the code might have some minor cosmetic
- issues. For example, suppose x and y are scalars and A is a Matrix, then
- while a human programmer might write "(x^2*y)*A^3", we generate:
- >>> octave_code(x**2*y*A**3)
- '(x.^2.*y)*A^3'
- Matrices are supported using Octave inline notation. When using
- ``assign_to`` with matrices, the name can be specified either as a string
- or as a ``MatrixSymbol``. The dimensions must align in the latter case.
- >>> from sympy import Matrix, MatrixSymbol
- >>> mat = Matrix([[x**2, sin(x), ceiling(x)]])
- >>> octave_code(mat, assign_to='A')
- 'A = [x.^2 sin(x) ceil(x)];'
- ``Piecewise`` expressions are implemented with logical masking by default.
- Alternatively, you can pass "inline=False" to use if-else conditionals.
- Note that if the ``Piecewise`` lacks a default term, represented by
- ``(expr, True)`` then an error will be thrown. This is to prevent
- generating an expression that may not evaluate to anything.
- >>> from sympy import Piecewise
- >>> pw = Piecewise((x + 1, x > 0), (x, True))
- >>> octave_code(pw, assign_to=tau)
- 'tau = ((x > 0).*(x + 1) + (~(x > 0)).*(x));'
- Note that any expression that can be generated normally can also exist
- inside a Matrix:
- >>> mat = Matrix([[x**2, pw, sin(x)]])
- >>> octave_code(mat, assign_to='A')
- 'A = [x.^2 ((x > 0).*(x + 1) + (~(x > 0)).*(x)) sin(x)];'
- Custom printing can be defined for certain types by passing a dictionary of
- "type" : "function" to the ``user_functions`` kwarg. Alternatively, the
- dictionary value can be a list of tuples i.e., [(argument_test,
- cfunction_string)]. This can be used to call a custom Octave function.
- >>> from sympy import Function
- >>> f = Function('f')
- >>> g = Function('g')
- >>> custom_functions = {
- ... "f": "existing_octave_fcn",
- ... "g": [(lambda x: x.is_Matrix, "my_mat_fcn"),
- ... (lambda x: not x.is_Matrix, "my_fcn")]
- ... }
- >>> mat = Matrix([[1, x]])
- >>> octave_code(f(x) + g(x) + g(mat), user_functions=custom_functions)
- 'existing_octave_fcn(x) + my_fcn(x) + my_mat_fcn([1 x])'
- Support for loops is provided through ``Indexed`` types. With
- ``contract=True`` these expressions will be turned into loops, whereas
- ``contract=False`` will just print the assignment expression that should be
- looped over:
- >>> from sympy import Eq, IndexedBase, Idx
- >>> len_y = 5
- >>> y = IndexedBase('y', shape=(len_y,))
- >>> t = IndexedBase('t', shape=(len_y,))
- >>> Dy = IndexedBase('Dy', shape=(len_y-1,))
- >>> i = Idx('i', len_y-1)
- >>> e = Eq(Dy[i], (y[i+1]-y[i])/(t[i+1]-t[i]))
- >>> octave_code(e.rhs, assign_to=e.lhs, contract=False)
- 'Dy(i) = (y(i + 1) - y(i))./(t(i + 1) - t(i));'
- """
- return OctaveCodePrinter(settings).doprint(expr, assign_to)
- def print_octave_code(expr, **settings):
- """Prints the Octave (or Matlab) representation of the given expression.
- See `octave_code` for the meaning of the optional arguments.
- """
- print(octave_code(expr, **settings))
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