将C99CodePrinter输出浮点数文字。

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英文:

getting C99CodePrinter to output float literals

问题

我正在尝试让sympy将一些公式转换为一种与C语言几乎相同的语言中的代码。然而,这种语言需要在浮点文字末尾加上'f',否则它会提升为双精度浮点数。即使sympy提供的文字被明确地指定为32位浮点数,它也不会这样做。我该如何做才能实现这个?

注意:

  1. 我在示例中直接使用了C99CodePrinter,因为我正在对其进行子类化。
  2. 目标语言是OpenCL,这就是为什么我们使用浮点数而不是双精度浮点数的原因(一些GPU不支持双精度浮点数)。

这是一个最简示例:

import sympy as sp
from sympy.printing.c import C99CodePrinter
import numpy as np

myPrinter = C99CodePrinter()

x = sp.symbols('x')
y = np.ones(1, dtype=np.float32)
print(myPrinter.doprint(y[0] * x))

我期望得到的是"1.0f*x",但实际上我得到的是"1.0*x"。

英文:

I'm trying to get sympy to convert some formulas into code in a language almost identical to C. However this language needs float literals to have the 'f' at the end other wise it promotes it to a double. Even when sympy is provided a literal that is explicitly typed as a 32bit float it doesn't do this. How do I make it do this?

notes:

  1. I'm using C99CodePrinter directly in my example because I'm subclassing it.
  2. target language is opencl, which is why we are using floats instead of doubles (some GPUs don't support doubles)

here is a minimal example:

import sympy as sp
from sympy.printing.c import C99CodePrinter
import numpy as np

myPrinter = C99CodePrinter()

x = sp.symbols('x')
y = np.ones(1,dtype=np.float32)
print(myPrinter.doprint(y[0]*x))

I was expecting to get "1.0f*x" but I actually get "1.0*x"

答案1

得分: 2

以下是您要求的代码的翻译部分:

所以在这里回答我的问题 正确的最小示例应该是

```python
import sympy as sp
from sympy.printing.c import C99CodePrinter
from sympy.codegen.ast import real, float32
import numpy as np

myPrinter = C99CodePrinter(settings={"type_aliases":{real: float32}})

x = sp.symbols('x')
y = np.ones(1,dtype=np.float32)
print(myPrinter.doprint(y[0]*x))

似乎打印机默认假定每个实数都是float64,除非像所示覆盖。


<details>
<summary>英文:</summary>

so answering my own question here. the correct minimal example would have been

import sympy as sp
from sympy.printing.c import C99CodePrinter
from sympy.codegen.ast import real, float32
import numpy as np

myPrinter = C99CodePrinter(settings={"type_aliases":{real: float32}})

x = sp.symbols('x')
y = np.ones(1,dtype=np.float32)
print(myPrinter.doprint(y[0]*x))

seems like the printer defaults to assuming every real number is float64 unless its overridden as shown.

</details>



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  • 本文由 发表于 2023年3月7日 22:45:18
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