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Python

import math
from decimal import Decimal, ROUND_HALF_EVEN
from utils import get_decimal_places, scientific_round
def calc_uncertainty(data_strs, res_str="0.05"):
# 转换为 Decimal 进行高精度计算
data = [Decimal(s) for s in data_strs]
res = Decimal(res_str)
n = len(data)
# 1. 计算平均值
places = get_decimal_places(data_strs)
sum_val = sum(data)
mean = sum_val / n
# 修改:平均值修约使用“四舍六入五凑偶”
mean_final = mean.quantize(Decimal('1.' + '0' * places), rounding=ROUND_HALF_EVEN)
# 2. 计算标准差 s
variance = sum((x - mean) ** 2 for x in data) / (n - 1)
s = Decimal(str(math.sqrt(float(variance))))
# 3. A类不确定度 u_A
u_A = s / Decimal(str(math.sqrt(n)))
# 4. B类不确定度 u_B (仪器误差)
u_B = res / Decimal(str(math.sqrt(3)))
# 5. 合成不确定度 u
u = Decimal(str(math.sqrt(float(u_A**2 + u_B**2))))
return mean_final, s, u_A, u_B, u
def format_final_result(mean, u):
"""
按照“四舍六入五凑偶”修约:
1. 不确定度 u 保留一位有效数字
2. 平均值末位与 u 对齐
"""
mean_final, u_final = scientific_round(mean, u)
return f"f = {mean_final} ± {u_final}"
if __name__ == "__main__":
# ... (后续输入输出逻辑保持不变)
print("请输入数据,用空格分隔:")
raw_input = input().split()
print("请输入仪器分度值(默认 0.05):")
res_input = input().strip() or "0.05"
mean_f, s, u_A, u_B, u = calc_uncertainty(raw_input, res_input)
print("\n--- 中间计算过程 (高精度展示) ---")
print(f"平均值 (原始精度): {mean_f}")
print(f"标准差 s: {s:.6f}")
print(f"A类不确定度 u_A: {u_A:.6f}")
print(f"B类不确定度 u_B: {u_B:.6f}")
print(f"合成不确定度 u: {u:.6f}")
print("\n--- 最终修约结果 (四舍六入五凑偶) ---")
print(format_final_result(mean_f, u))