Adding all project files

venv/Lib/site-packages/sympy/codegen/cfunctions.py

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+"""
+This module contains SymPy functions mathcin corresponding to special math functions in the
+C standard library (since C99, also available in C++11).
+
+The functions defined in this module allows the user to express functions such as ``expm1``
+as a SymPy function for symbolic manipulation.
+
+"""
+from sympy.core.function import ArgumentIndexError, Function
+from sympy.core.numbers import Rational
+from sympy.core.power import Pow
+from sympy.core.singleton import S
+from sympy.functions.elementary.exponential import exp, log
+from sympy.functions.elementary.miscellaneous import sqrt
+from sympy.logic.boolalg import BooleanFunction, true, false
+
+def _expm1(x):
+    return exp(x) - S.One
+
+
+class expm1(Function):
+    """
+    Represents the exponential function minus one.
+
+    Explanation
+    ===========
+
+    The benefit of using ``expm1(x)`` over ``exp(x) - 1``
+    is that the latter is prone to cancellation under finite precision
+    arithmetic when x is close to zero.
+
+    Examples
+    ========
+
+    >>> from sympy.abc import x
+    >>> from sympy.codegen.cfunctions import expm1
+    >>> '%.0e' % expm1(1e-99).evalf()
+    '1e-99'
+    >>> from math import exp
+    >>> exp(1e-99) - 1
+    0.0
+    >>> expm1(x).diff(x)
+    exp(x)
+
+    See Also
+    ========
+
+    log1p
+    """
+    nargs = 1
+
+    def fdiff(self, argindex=1):
+        """
+        Returns the first derivative of this function.
+        """
+        if argindex == 1:
+            return exp(*self.args)
+        else:
+            raise ArgumentIndexError(self, argindex)
+
+    def _eval_expand_func(self, **hints):
+        return _expm1(*self.args)
+
+    def _eval_rewrite_as_exp(self, arg, **kwargs):
+        return exp(arg) - S.One
+
+    _eval_rewrite_as_tractable = _eval_rewrite_as_exp
+
+    @classmethod
+    def eval(cls, arg):
+        exp_arg = exp.eval(arg)
+        if exp_arg is not None:
+            return exp_arg - S.One
+
+    def _eval_is_real(self):
+        return self.args[0].is_real
+
+    def _eval_is_finite(self):
+        return self.args[0].is_finite
+
+
+def _log1p(x):
+    return log(x + S.One)
+
+
+class log1p(Function):
+    """
+    Represents the natural logarithm of a number plus one.
+
+    Explanation
+    ===========
+
+    The benefit of using ``log1p(x)`` over ``log(x + 1)``
+    is that the latter is prone to cancellation under finite precision
+    arithmetic when x is close to zero.
+
+    Examples
+    ========
+
+    >>> from sympy.abc import x
+    >>> from sympy.codegen.cfunctions import log1p
+    >>> from sympy import expand_log
+    >>> '%.0e' % expand_log(log1p(1e-99)).evalf()
+    '1e-99'
+    >>> from math import log
+    >>> log(1 + 1e-99)
+    0.0
+    >>> log1p(x).diff(x)
+    1/(x + 1)
+
+    See Also
+    ========
+
+    expm1
+    """
+    nargs = 1
+
+
+    def fdiff(self, argindex=1):
+        """
+        Returns the first derivative of this function.
+        """
+        if argindex == 1:
+            return S.One/(self.args[0] + S.One)
+        else:
+            raise ArgumentIndexError(self, argindex)
+
+
+    def _eval_expand_func(self, **hints):
+        return _log1p(*self.args)
+
+    def _eval_rewrite_as_log(self, arg, **kwargs):
+        return _log1p(arg)
+
+    _eval_rewrite_as_tractable = _eval_rewrite_as_log
+
+    @classmethod
+    def eval(cls, arg):
+        if arg.is_Rational:
+            return log(arg + S.One)
+        elif not arg.is_Float:  # not safe to add 1 to Float
+            return log.eval(arg + S.One)
+        elif arg.is_number:
+            return log(Rational(arg) + S.One)
+
+    def _eval_is_real(self):
+        return (self.args[0] + S.One).is_nonnegative
+
+    def _eval_is_finite(self):
+        if (self.args[0] + S.One).is_zero:
+            return False
+        return self.args[0].is_finite
+
+    def _eval_is_positive(self):
+        return self.args[0].is_positive
+
+    def _eval_is_zero(self):
+        return self.args[0].is_zero
+
+    def _eval_is_nonnegative(self):
+        return self.args[0].is_nonnegative
+
+_Two = S(2)
+
+def _exp2(x):
+    return Pow(_Two, x)
+
+class exp2(Function):
+    """
+    Represents the exponential function with base two.
+
+    Explanation
+    ===========
+
+    The benefit of using ``exp2(x)`` over ``2**x``
+    is that the latter is not as efficient under finite precision
+    arithmetic.
+
+    Examples
+    ========
+
+    >>> from sympy.abc import x
+    >>> from sympy.codegen.cfunctions import exp2
+    >>> exp2(2).evalf() == 4.0
+    True
+    >>> exp2(x).diff(x)
+    log(2)*exp2(x)
+
+    See Also
+    ========
+
+    log2
+    """
+    nargs = 1
+
+
+    def fdiff(self, argindex=1):
+        """
+        Returns the first derivative of this function.
+        """
+        if argindex == 1:
+            return self*log(_Two)
+        else:
+            raise ArgumentIndexError(self, argindex)
+
+    def _eval_rewrite_as_Pow(self, arg, **kwargs):
+        return _exp2(arg)
+
+    _eval_rewrite_as_tractable = _eval_rewrite_as_Pow
+
+    def _eval_expand_func(self, **hints):
+        return _exp2(*self.args)
+
+    @classmethod
+    def eval(cls, arg):
+        if arg.is_number:
+            return _exp2(arg)
+
+
+def _log2(x):
+    return log(x)/log(_Two)
+
+
+class log2(Function):
+    """
+    Represents the logarithm function with base two.
+
+    Explanation
+    ===========
+
+    The benefit of using ``log2(x)`` over ``log(x)/log(2)``
+    is that the latter is not as efficient under finite precision
+    arithmetic.
+
+    Examples
+    ========
+
+    >>> from sympy.abc import x
+    >>> from sympy.codegen.cfunctions import log2
+    >>> log2(4).evalf() == 2.0
+    True
+    >>> log2(x).diff(x)
+    1/(x*log(2))
+
+    See Also
+    ========
+
+    exp2
+    log10
+    """
+    nargs = 1
+
+    def fdiff(self, argindex=1):
+        """
+        Returns the first derivative of this function.
+        """
+        if argindex == 1:
+            return S.One/(log(_Two)*self.args[0])
+        else:
+            raise ArgumentIndexError(self, argindex)
+
+
+    @classmethod
+    def eval(cls, arg):
+        if arg.is_number:
+            result = log.eval(arg, base=_Two)
+            if result.is_Atom:
+                return result
+        elif arg.is_Pow and arg.base == _Two:
+            return arg.exp
+
+    def _eval_evalf(self, *args, **kwargs):
+        return self.rewrite(log).evalf(*args, **kwargs)
+
+    def _eval_expand_func(self, **hints):
+        return _log2(*self.args)
+
+    def _eval_rewrite_as_log(self, arg, **kwargs):
+        return _log2(arg)
+
+    _eval_rewrite_as_tractable = _eval_rewrite_as_log
+
+
+def _fma(x, y, z):
+    return x*y + z
+
+
+class fma(Function):
+    """
+    Represents "fused multiply add".
+
+    Explanation
+    ===========
+
+    The benefit of using ``fma(x, y, z)`` over ``x*y + z``
+    is that, under finite precision arithmetic, the former is
+    supported by special instructions on some CPUs.
+
+    Examples
+    ========
+
+    >>> from sympy.abc import x, y, z
+    >>> from sympy.codegen.cfunctions import fma
+    >>> fma(x, y, z).diff(x)
+    y
+
+    """
+    nargs = 3
+
+    def fdiff(self, argindex=1):
+        """
+        Returns the first derivative of this function.
+        """
+        if argindex in (1, 2):
+            return self.args[2 - argindex]
+        elif argindex == 3:
+            return S.One
+        else:
+            raise ArgumentIndexError(self, argindex)
+
+
+    def _eval_expand_func(self, **hints):
+        return _fma(*self.args)
+
+    def _eval_rewrite_as_tractable(self, arg, limitvar=None, **kwargs):
+        return _fma(arg)
+
+
+_Ten = S(10)
+
+
+def _log10(x):
+    return log(x)/log(_Ten)
+
+
+class log10(Function):
+    """
+    Represents the logarithm function with base ten.
+
+    Examples
+    ========
+
+    >>> from sympy.abc import x
+    >>> from sympy.codegen.cfunctions import log10
+    >>> log10(100).evalf() == 2.0
+    True
+    >>> log10(x).diff(x)
+    1/(x*log(10))
+
+    See Also
+    ========
+
+    log2
+    """
+    nargs = 1
+
+    def fdiff(self, argindex=1):
+        """
+        Returns the first derivative of this function.
+        """
+        if argindex == 1:
+            return S.One/(log(_Ten)*self.args[0])
+        else:
+            raise ArgumentIndexError(self, argindex)
+
+
+    @classmethod
+    def eval(cls, arg):
+        if arg.is_number:
+            result = log.eval(arg, base=_Ten)
+            if result.is_Atom:
+                return result
+        elif arg.is_Pow and arg.base == _Ten:
+            return arg.exp
+
+    def _eval_expand_func(self, **hints):
+        return _log10(*self.args)
+
+    def _eval_rewrite_as_log(self, arg, **kwargs):
+        return _log10(arg)
+
+    _eval_rewrite_as_tractable = _eval_rewrite_as_log
+
+
+def _Sqrt(x):
+    return Pow(x, S.Half)
+
+
+class Sqrt(Function):  # 'sqrt' already defined in sympy.functions.elementary.miscellaneous
+    """
+    Represents the square root function.
+
+    Explanation
+    ===========
+
+    The reason why one would use ``Sqrt(x)`` over ``sqrt(x)``
+    is that the latter is internally represented as ``Pow(x, S.Half)`` which
+    may not be what one wants when doing code-generation.
+
+    Examples
+    ========
+
+    >>> from sympy.abc import x
+    >>> from sympy.codegen.cfunctions import Sqrt
+    >>> Sqrt(x)
+    Sqrt(x)
+    >>> Sqrt(x).diff(x)
+    1/(2*sqrt(x))
+
+    See Also
+    ========
+
+    Cbrt
+    """
+    nargs = 1
+
+    def fdiff(self, argindex=1):
+        """
+        Returns the first derivative of this function.
+        """
+        if argindex == 1:
+            return Pow(self.args[0], Rational(-1, 2))/_Two
+        else:
+            raise ArgumentIndexError(self, argindex)
+
+    def _eval_expand_func(self, **hints):
+        return _Sqrt(*self.args)
+
+    def _eval_rewrite_as_Pow(self, arg, **kwargs):
+        return _Sqrt(arg)
+
+    _eval_rewrite_as_tractable = _eval_rewrite_as_Pow
+
+
+def _Cbrt(x):
+    return Pow(x, Rational(1, 3))
+
+
+class Cbrt(Function):  # 'cbrt' already defined in sympy.functions.elementary.miscellaneous
+    """
+    Represents the cube root function.
+
+    Explanation
+    ===========
+
+    The reason why one would use ``Cbrt(x)`` over ``cbrt(x)``
+    is that the latter is internally represented as ``Pow(x, Rational(1, 3))`` which
+    may not be what one wants when doing code-generation.
+
+    Examples
+    ========
+
+    >>> from sympy.abc import x
+    >>> from sympy.codegen.cfunctions import Cbrt
+    >>> Cbrt(x)
+    Cbrt(x)
+    >>> Cbrt(x).diff(x)
+    1/(3*x**(2/3))
+
+    See Also
+    ========
+
+    Sqrt
+    """
+    nargs = 1
+
+    def fdiff(self, argindex=1):
+        """
+        Returns the first derivative of this function.
+        """
+        if argindex == 1:
+            return Pow(self.args[0], Rational(-_Two/3))/3
+        else:
+            raise ArgumentIndexError(self, argindex)
+
+
+    def _eval_expand_func(self, **hints):
+        return _Cbrt(*self.args)
+
+    def _eval_rewrite_as_Pow(self, arg, **kwargs):
+        return _Cbrt(arg)
+
+    _eval_rewrite_as_tractable = _eval_rewrite_as_Pow
+
+
+def _hypot(x, y):
+    return sqrt(Pow(x, 2) + Pow(y, 2))
+
+
+class hypot(Function):
+    """
+    Represents the hypotenuse function.
+
+    Explanation
+    ===========
+
+    The hypotenuse function is provided by e.g. the math library
+    in the C99 standard, hence one may want to represent the function
+    symbolically when doing code-generation.
+
+    Examples
+    ========
+
+    >>> from sympy.abc import x, y
+    >>> from sympy.codegen.cfunctions import hypot
+    >>> hypot(3, 4).evalf() == 5.0
+    True
+    >>> hypot(x, y)
+    hypot(x, y)
+    >>> hypot(x, y).diff(x)
+    x/hypot(x, y)
+
+    """
+    nargs = 2
+
+    def fdiff(self, argindex=1):
+        """
+        Returns the first derivative of this function.
+        """
+        if argindex in (1, 2):
+            return 2*self.args[argindex-1]/(_Two*self.func(*self.args))
+        else:
+            raise ArgumentIndexError(self, argindex)
+
+
+    def _eval_expand_func(self, **hints):
+        return _hypot(*self.args)
+
+    def _eval_rewrite_as_Pow(self, arg, **kwargs):
+        return _hypot(arg)
+
+    _eval_rewrite_as_tractable = _eval_rewrite_as_Pow
+
+
+class isnan(BooleanFunction):
+    nargs = 1
+
+    @classmethod
+    def eval(cls, arg):
+        if arg is S.NaN:
+            return true
+        elif arg.is_number:
+            return false
+        else:
+            return None
+
+
+class isinf(BooleanFunction):
+    nargs = 1
+
+    @classmethod
+    def eval(cls, arg):
+        if arg.is_infinite:
+            return true
+        elif arg.is_finite:
+            return false
+        else:
+            return None