[英]Converting fractions to floating point
我正在嘗試將分數轉換為浮點數並將其用於比較。 但這些值太小,對於布爾變量的結果,它返回 true。 我的轉換正確嗎? 或者我應該以另一種我不知道的方式來做嗎?
一個測試用例:
// result is -0.0074
float coilh0re = fr32_to_float(GO_coil_H[0].re)*0.8f;
// result is -0.0092
float coilrefundamental = fr32_to_float(CoilEepromData.coilboardhspule.reFundamental);
// result is -0.01123
float coilh0re2 = fr32_to_float(GO_coil_H[0].re)*1.2f;
-0.0074>-0.0092> -0.01123
這是代碼的片段
bool resultA = fr32_to_float(GO_coil_H[0].re)*0.8f < fr32_to_float(CoilEepromData.coilboardhspule.reFundamental) ? 1 : 0;
bool resultB = fr32_to_float(CoilEepromData.coilboardhspule.reFundamental) <= fr32_to_float(GO_coil_H[0].re)*1.2f ? 1 : 0;
bool resultAB = !(resultA & resultB); // always true
bool resultC = fr32_to_float(GO_coil_H[1].re)*0.8f < fr32_to_float(CoilEepromData.coilboardhspule.reHarmonic) ? 1:0;
bool resultD = fr32_to_float(CoilEepromData.coilboardhspule.reHarmonic) <= fr32_to_float(GO_coil_H[1].re)*1.2f ? 1:0;
bool resultCD = !(resultC & resultD); // always true
bool resultE = fr32_to_float(GO_coil_H[0].im)*0.8f < fr32_to_float(CoilEepromData.coilboardhspule.imFundamental)? 1 : 0;
bool resultF = fr32_to_float(CoilEepromData.coilboardhspule.imFundamental) <= fr32_to_float(GO_coil_H[0].im)*1.2f ? 1 : 0;
bool resultEF = !(resultE & resultF);// always true
bool resultG = fr32_to_float(GO_coil_H[1].im)*0.8f < CoilEepromData.coilboardhspule.imHarmonic ? 1 : 0;
bool resultH = fr32_to_float(CoilEepromData.coilboardhspule.imHarmonic) <= fr32_to_float(GO_coil_H[1].im)*1.2f ? 1 : 0;
bool resultGH = !(resultG & resultH);// always true
if(! ((fr32_to_float(GO_coil_H[0].re)*0.8f < fr32_to_float(CoilEepromData.coilboardhspule.reFundamental)) && (fr32_to_float(CoilEepromData.coilboardhspule.reFundamental) <= fr32_to_float(GO_coil_H[0].re)*1.2f) )
|| ! ((fr32_to_float(GO_coil_H[1].re)*0.8f < fr32_to_float(CoilEepromData.coilboardhspule.reHarmonic)) && (fr32_to_float(CoilEepromData.coilboardhspule.reHarmonic) <= fr32_to_float(GO_coil_H[1].re)*1.2f) )
|| ! ((fr32_to_float(GO_coil_H[0].im)*0.8f < fr32_to_float(CoilEepromData.coilboardhspule.imFundamental)) && (fr32_to_float(CoilEepromData.coilboardhspule.imFundamental) <= fr32_to_float(GO_coil_H[0].im)*1.2f) )
|| ! ((fr32_to_float(GO_coil_H[1].im)*0.8f < fr32_to_float(CoilEepromData.coilboardhspule.imHarmonic)) && (fr32_to_float(CoilEepromData.coilboardhspule.imHarmonic) <= fr32_to_float(GO_coil_H[1].im)*1.2f) ) )
{
eUserCode = E_USER_SOIL_FAILED;
eProcessState = E_ERROR_HANDLING;
}
}
如果出現 OP 想要測試值reFundamental
是否在re
+/-20% 范圍內。 這不是float
精度問題,而是數學問題。
// Simplified problem
float re = -0.01123f/1.2f;
float reFundamental = -0.0092f;
bool resultA = re*0.8f < reFundamental;
bool resultB = reFundamental <= re*1.2f;
bool resultAB = !(resultA & resultB); // always true
但是值是負的,所以<
和<=
應該顛倒。
各種替代品。 示例:(根據口味調整)
bool in_range(float x, float limit, float factor) {
float limitp = limit*(1.0f + factor);
float limitm = limit*(1.0f - factor);
if (x > limitm) return x <= limitp;
if (x < limitm) return x >= limitp;
return x == limitp;
}
bool resultAB = !in_range(fr32_to_float(CoilEepromData.coilboardhspule.reFundamental),
fr32_to_float(GO_coil_H[0].re), 0.20);
如果您想比較分數 - 根本不要使用浮點數。 將它們轉換為相同的分母並比較分子。
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.