626 lines
21 KiB
Python
626 lines
21 KiB
Python
"""
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Rust code printer
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The `RustCodePrinter` converts SymPy expressions into Rust expressions.
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A complete code generator, which uses `rust_code` extensively, can be found
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in `sympy.utilities.codegen`. The `codegen` module can be used to generate
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complete source code files.
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"""
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# Possible Improvement
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#
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# * make sure we follow Rust Style Guidelines_
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# * make use of pattern matching
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# * better support for reference
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# * generate generic code and use trait to make sure they have specific methods
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# * use crates_ to get more math support
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# - num_
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# + BigInt_, BigUint_
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# + Complex_
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# + Rational64_, Rational32_, BigRational_
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#
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# .. _crates: https://crates.io/
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# .. _Guidelines: https://github.com/rust-lang/rust/tree/master/src/doc/style
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# .. _num: http://rust-num.github.io/num/num/
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# .. _BigInt: http://rust-num.github.io/num/num/bigint/struct.BigInt.html
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# .. _BigUint: http://rust-num.github.io/num/num/bigint/struct.BigUint.html
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# .. _Complex: http://rust-num.github.io/num/num/complex/struct.Complex.html
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# .. _Rational32: http://rust-num.github.io/num/num/rational/type.Rational32.html
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# .. _Rational64: http://rust-num.github.io/num/num/rational/type.Rational64.html
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# .. _BigRational: http://rust-num.github.io/num/num/rational/type.BigRational.html
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from __future__ import annotations
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from typing import Any
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from sympy.core import S, Rational, Float, Lambda
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from sympy.core.numbers import equal_valued
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from sympy.printing.codeprinter import CodePrinter
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# Rust's methods for integer and float can be found at here :
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#
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# * `Rust - Primitive Type f64 <https://doc.rust-lang.org/std/primitive.f64.html>`_
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# * `Rust - Primitive Type i64 <https://doc.rust-lang.org/std/primitive.i64.html>`_
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#
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# Function Style :
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#
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# 1. args[0].func(args[1:]), method with arguments
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# 2. args[0].func(), method without arguments
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# 3. args[1].func(), method without arguments (e.g. (e, x) => x.exp())
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# 4. func(args), function with arguments
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# dictionary mapping SymPy function to (argument_conditions, Rust_function).
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# Used in RustCodePrinter._print_Function(self)
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# f64 method in Rust
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known_functions = {
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# "": "is_nan",
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# "": "is_infinite",
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# "": "is_finite",
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# "": "is_normal",
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# "": "classify",
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"floor": "floor",
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"ceiling": "ceil",
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# "": "round",
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# "": "trunc",
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# "": "fract",
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"Abs": "abs",
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"sign": "signum",
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# "": "is_sign_positive",
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# "": "is_sign_negative",
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# "": "mul_add",
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"Pow": [(lambda base, exp: equal_valued(exp, -1), "recip", 2), # 1.0/x
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(lambda base, exp: equal_valued(exp, 0.5), "sqrt", 2), # x ** 0.5
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(lambda base, exp: equal_valued(exp, -0.5), "sqrt().recip", 2), # 1/(x ** 0.5)
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(lambda base, exp: exp == Rational(1, 3), "cbrt", 2), # x ** (1/3)
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(lambda base, exp: equal_valued(base, 2), "exp2", 3), # 2 ** x
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(lambda base, exp: exp.is_integer, "powi", 1), # x ** y, for i32
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(lambda base, exp: not exp.is_integer, "powf", 1)], # x ** y, for f64
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"exp": [(lambda exp: True, "exp", 2)], # e ** x
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"log": "ln",
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# "": "log", # number.log(base)
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# "": "log2",
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# "": "log10",
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# "": "to_degrees",
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# "": "to_radians",
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"Max": "max",
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"Min": "min",
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# "": "hypot", # (x**2 + y**2) ** 0.5
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"sin": "sin",
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"cos": "cos",
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"tan": "tan",
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"asin": "asin",
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"acos": "acos",
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"atan": "atan",
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"atan2": "atan2",
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# "": "sin_cos",
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# "": "exp_m1", # e ** x - 1
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# "": "ln_1p", # ln(1 + x)
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"sinh": "sinh",
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"cosh": "cosh",
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"tanh": "tanh",
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"asinh": "asinh",
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"acosh": "acosh",
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"atanh": "atanh",
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"sqrt": "sqrt", # To enable automatic rewrites
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}
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# i64 method in Rust
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# known_functions_i64 = {
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# "": "min_value",
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# "": "max_value",
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# "": "from_str_radix",
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# "": "count_ones",
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# "": "count_zeros",
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# "": "leading_zeros",
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# "": "trainling_zeros",
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# "": "rotate_left",
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# "": "rotate_right",
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# "": "swap_bytes",
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# "": "from_be",
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# "": "from_le",
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# "": "to_be", # to big endian
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# "": "to_le", # to little endian
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# "": "checked_add",
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# "": "checked_sub",
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# "": "checked_mul",
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# "": "checked_div",
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# "": "checked_rem",
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# "": "checked_neg",
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# "": "checked_shl",
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# "": "checked_shr",
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# "": "checked_abs",
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# "": "saturating_add",
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# "": "saturating_sub",
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# "": "saturating_mul",
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# "": "wrapping_add",
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# "": "wrapping_sub",
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# "": "wrapping_mul",
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# "": "wrapping_div",
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# "": "wrapping_rem",
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# "": "wrapping_neg",
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# "": "wrapping_shl",
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# "": "wrapping_shr",
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# "": "wrapping_abs",
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# "": "overflowing_add",
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# "": "overflowing_sub",
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# "": "overflowing_mul",
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# "": "overflowing_div",
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# "": "overflowing_rem",
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# "": "overflowing_neg",
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# "": "overflowing_shl",
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# "": "overflowing_shr",
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# "": "overflowing_abs",
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# "Pow": "pow",
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# "Abs": "abs",
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# "sign": "signum",
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# "": "is_positive",
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# "": "is_negnative",
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# }
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# These are the core reserved words in the Rust language. Taken from:
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# http://doc.rust-lang.org/grammar.html#keywords
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reserved_words = ['abstract',
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'alignof',
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'as',
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'become',
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'box',
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'break',
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'const',
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'continue',
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'crate',
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'do',
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'else',
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'enum',
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'extern',
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'false',
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'final',
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'fn',
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'for',
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'if',
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'impl',
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'in',
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'let',
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'loop',
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'macro',
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'match',
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'mod',
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'move',
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'mut',
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'offsetof',
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'override',
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'priv',
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'proc',
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'pub',
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'pure',
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'ref',
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'return',
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'Self',
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'self',
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'sizeof',
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'static',
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'struct',
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'super',
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'trait',
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'true',
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'type',
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'typeof',
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'unsafe',
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'unsized',
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'use',
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'virtual',
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'where',
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'while',
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'yield']
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class RustCodePrinter(CodePrinter):
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"""A printer to convert SymPy expressions to strings of Rust code"""
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printmethod = "_rust_code"
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language = "Rust"
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_default_settings: dict[str, Any] = {
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'order': None,
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'full_prec': 'auto',
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'precision': 17,
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'user_functions': {},
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'human': True,
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'contract': True,
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'dereference': set(),
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'error_on_reserved': False,
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'reserved_word_suffix': '_',
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'inline': False,
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}
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def __init__(self, settings={}):
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CodePrinter.__init__(self, settings)
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self.known_functions = dict(known_functions)
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userfuncs = settings.get('user_functions', {})
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self.known_functions.update(userfuncs)
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self._dereference = set(settings.get('dereference', []))
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self.reserved_words = set(reserved_words)
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def _rate_index_position(self, p):
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return p*5
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def _get_statement(self, codestring):
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return "%s;" % codestring
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def _get_comment(self, text):
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return "// %s" % text
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def _declare_number_const(self, name, value):
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return "const %s: f64 = %s;" % (name, value)
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def _format_code(self, lines):
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return self.indent_code(lines)
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def _traverse_matrix_indices(self, mat):
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rows, cols = mat.shape
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return ((i, j) for i in range(rows) for j in range(cols))
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def _get_loop_opening_ending(self, indices):
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open_lines = []
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close_lines = []
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loopstart = "for %(var)s in %(start)s..%(end)s {"
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for i in indices:
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# Rust arrays start at 0 and end at dimension-1
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open_lines.append(loopstart % {
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'var': self._print(i),
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'start': self._print(i.lower),
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'end': self._print(i.upper + 1)})
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close_lines.append("}")
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return open_lines, close_lines
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def _print_caller_var(self, expr):
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if len(expr.args) > 1:
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# for something like `sin(x + y + z)`,
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# make sure we can get '(x + y + z).sin()'
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# instead of 'x + y + z.sin()'
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return '(' + self._print(expr) + ')'
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elif expr.is_number:
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return self._print(expr, _type=True)
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else:
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return self._print(expr)
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def _print_Function(self, expr):
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"""
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basic function for printing `Function`
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Function Style :
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1. args[0].func(args[1:]), method with arguments
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2. args[0].func(), method without arguments
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3. args[1].func(), method without arguments (e.g. (e, x) => x.exp())
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4. func(args), function with arguments
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"""
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if expr.func.__name__ in self.known_functions:
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cond_func = self.known_functions[expr.func.__name__]
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func = None
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style = 1
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if isinstance(cond_func, str):
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func = cond_func
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else:
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for cond, func, style in cond_func:
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if cond(*expr.args):
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break
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if func is not None:
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if style == 1:
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ret = "%(var)s.%(method)s(%(args)s)" % {
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'var': self._print_caller_var(expr.args[0]),
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'method': func,
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'args': self.stringify(expr.args[1:], ", ") if len(expr.args) > 1 else ''
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}
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elif style == 2:
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ret = "%(var)s.%(method)s()" % {
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'var': self._print_caller_var(expr.args[0]),
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'method': func,
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}
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elif style == 3:
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ret = "%(var)s.%(method)s()" % {
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'var': self._print_caller_var(expr.args[1]),
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'method': func,
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}
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else:
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ret = "%(func)s(%(args)s)" % {
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'func': func,
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'args': self.stringify(expr.args, ", "),
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}
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return ret
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elif hasattr(expr, '_imp_') and isinstance(expr._imp_, Lambda):
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# inlined function
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return self._print(expr._imp_(*expr.args))
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elif expr.func.__name__ in self._rewriteable_functions:
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# Simple rewrite to supported function possible
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target_f, required_fs = self._rewriteable_functions[expr.func.__name__]
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if self._can_print(target_f) and all(self._can_print(f) for f in required_fs):
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return self._print(expr.rewrite(target_f))
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else:
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return self._print_not_supported(expr)
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def _print_Pow(self, expr):
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if expr.base.is_integer and not expr.exp.is_integer:
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expr = type(expr)(Float(expr.base), expr.exp)
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return self._print(expr)
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return self._print_Function(expr)
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def _print_Float(self, expr, _type=False):
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ret = super()._print_Float(expr)
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if _type:
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return ret + '_f64'
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else:
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return ret
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def _print_Integer(self, expr, _type=False):
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ret = super()._print_Integer(expr)
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if _type:
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return ret + '_i32'
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else:
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return ret
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def _print_Rational(self, expr):
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p, q = int(expr.p), int(expr.q)
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return '%d_f64/%d.0' % (p, q)
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def _print_Relational(self, expr):
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lhs_code = self._print(expr.lhs)
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rhs_code = self._print(expr.rhs)
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op = expr.rel_op
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return "{} {} {}".format(lhs_code, op, rhs_code)
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def _print_Indexed(self, expr):
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# calculate index for 1d array
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dims = expr.shape
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elem = S.Zero
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offset = S.One
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for i in reversed(range(expr.rank)):
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elem += expr.indices[i]*offset
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offset *= dims[i]
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return "%s[%s]" % (self._print(expr.base.label), self._print(elem))
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def _print_Idx(self, expr):
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return expr.label.name
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def _print_Dummy(self, expr):
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return expr.name
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def _print_Exp1(self, expr, _type=False):
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return "E"
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def _print_Pi(self, expr, _type=False):
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return 'PI'
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def _print_Infinity(self, expr, _type=False):
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return 'INFINITY'
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def _print_NegativeInfinity(self, expr, _type=False):
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return 'NEG_INFINITY'
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def _print_BooleanTrue(self, expr, _type=False):
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return "true"
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def _print_BooleanFalse(self, expr, _type=False):
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return "false"
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def _print_bool(self, expr, _type=False):
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return str(expr).lower()
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def _print_NaN(self, expr, _type=False):
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return "NAN"
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def _print_Piecewise(self, expr):
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if expr.args[-1].cond != True:
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# We need the last conditional to be a True, otherwise the resulting
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# function may not return a result.
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raise ValueError("All Piecewise expressions must contain an "
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"(expr, True) statement to be used as a default "
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"condition. Without one, the generated "
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"expression may not evaluate to anything under "
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"some condition.")
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lines = []
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for i, (e, c) in enumerate(expr.args):
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if i == 0:
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lines.append("if (%s) {" % self._print(c))
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elif i == len(expr.args) - 1 and c == True:
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lines[-1] += " else {"
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else:
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lines[-1] += " else if (%s) {" % self._print(c)
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code0 = self._print(e)
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lines.append(code0)
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lines.append("}")
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if self._settings['inline']:
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return " ".join(lines)
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else:
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return "\n".join(lines)
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def _print_ITE(self, expr):
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from sympy.functions import Piecewise
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return self._print(expr.rewrite(Piecewise, deep=False))
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def _print_MatrixBase(self, A):
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if A.cols == 1:
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return "[%s]" % ", ".join(self._print(a) for a in A)
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else:
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raise ValueError("Full Matrix Support in Rust need Crates (https://crates.io/keywords/matrix).")
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def _print_SparseRepMatrix(self, mat):
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# do not allow sparse matrices to be made dense
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return self._print_not_supported(mat)
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def _print_MatrixElement(self, expr):
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return "%s[%s]" % (expr.parent,
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expr.j + expr.i*expr.parent.shape[1])
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def _print_Symbol(self, expr):
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name = super()._print_Symbol(expr)
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if expr in self._dereference:
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return '(*%s)' % name
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else:
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return name
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def _print_Assignment(self, expr):
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from sympy.tensor.indexed import IndexedBase
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lhs = expr.lhs
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rhs = expr.rhs
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if self._settings["contract"] and (lhs.has(IndexedBase) or
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rhs.has(IndexedBase)):
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# Here we check if there is looping to be done, and if so
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# print the required loops.
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return self._doprint_loops(rhs, lhs)
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else:
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lhs_code = self._print(lhs)
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rhs_code = self._print(rhs)
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return self._get_statement("%s = %s" % (lhs_code, rhs_code))
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def indent_code(self, code):
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"""Accepts a string of code or a list of code lines"""
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if isinstance(code, str):
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code_lines = self.indent_code(code.splitlines(True))
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return ''.join(code_lines)
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tab = " "
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inc_token = ('{', '(', '{\n', '(\n')
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dec_token = ('}', ')')
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code = [ line.lstrip(' \t') for line in code ]
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increase = [ int(any(map(line.endswith, inc_token))) for line in code ]
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decrease = [ int(any(map(line.startswith, dec_token)))
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for line in code ]
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pretty = []
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level = 0
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for n, line in enumerate(code):
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if line in ('', '\n'):
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pretty.append(line)
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continue
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level -= decrease[n]
|
|
pretty.append("%s%s" % (tab*level, line))
|
|
level += increase[n]
|
|
return pretty
|
|
|
|
|
|
def rust_code(expr, assign_to=None, **settings):
|
|
"""Converts an expr to a string of Rust code
|
|
|
|
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 is helpful in case of
|
|
line-wrapping, or for expressions that generate multi-line statements.
|
|
precision : integer, optional
|
|
The precision for numbers such as pi [default=15].
|
|
user_functions : dict, optional
|
|
A dictionary where the keys are string representations of either
|
|
``FunctionClass`` or ``UndefinedFunction`` instances and the values
|
|
are their desired C string representations. Alternatively, the
|
|
dictionary value can be a list of tuples i.e. [(argument_test,
|
|
cfunction_string)]. See below for examples.
|
|
dereference : iterable, optional
|
|
An iterable of symbols that should be dereferenced in the printed code
|
|
expression. These would be values passed by address to the function.
|
|
For example, if ``dereference=[a]``, the resulting code would print
|
|
``(*a)`` instead of ``a``.
|
|
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].
|
|
|
|
Examples
|
|
========
|
|
|
|
>>> from sympy import rust_code, symbols, Rational, sin, ceiling, Abs, Function
|
|
>>> x, tau = symbols("x, tau")
|
|
>>> rust_code((2*tau)**Rational(7, 2))
|
|
'8*1.4142135623731*tau.powf(7_f64/2.0)'
|
|
>>> rust_code(sin(x), assign_to="s")
|
|
's = x.sin();'
|
|
|
|
Simple 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)].
|
|
|
|
>>> custom_functions = {
|
|
... "ceiling": "CEIL",
|
|
... "Abs": [(lambda x: not x.is_integer, "fabs", 4),
|
|
... (lambda x: x.is_integer, "ABS", 4)],
|
|
... "func": "f"
|
|
... }
|
|
>>> func = Function('func')
|
|
>>> rust_code(func(Abs(x) + ceiling(x)), user_functions=custom_functions)
|
|
'(fabs(x) + x.CEIL()).f()'
|
|
|
|
``Piecewise`` expressions are converted into conditionals. If an
|
|
``assign_to`` variable is provided an if statement is created, otherwise
|
|
the ternary operator is used. 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
|
|
>>> expr = Piecewise((x + 1, x > 0), (x, True))
|
|
>>> print(rust_code(expr, tau))
|
|
tau = if (x > 0) {
|
|
x + 1
|
|
} else {
|
|
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]))
|
|
>>> rust_code(e.rhs, assign_to=e.lhs, contract=False)
|
|
'Dy[i] = (y[i + 1] - y[i])/(t[i + 1] - t[i]);'
|
|
|
|
Matrices are also supported, but a ``MatrixSymbol`` of the same dimensions
|
|
must be provided to ``assign_to``. Note that any expression that can be
|
|
generated normally can also exist inside a Matrix:
|
|
|
|
>>> from sympy import Matrix, MatrixSymbol
|
|
>>> mat = Matrix([x**2, Piecewise((x + 1, x > 0), (x, True)), sin(x)])
|
|
>>> A = MatrixSymbol('A', 3, 1)
|
|
>>> print(rust_code(mat, A))
|
|
A = [x.powi(2), if (x > 0) {
|
|
x + 1
|
|
} else {
|
|
x
|
|
}, x.sin()];
|
|
"""
|
|
|
|
return RustCodePrinter(settings).doprint(expr, assign_to)
|
|
|
|
|
|
def print_rust_code(expr, **settings):
|
|
"""Prints Rust representation of the given expression."""
|
|
print(rust_code(expr, **settings))
|