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  1. #include <iostream>
  2. #include <vector>
  3. #include <cmath>
  4.  
  5. using namespace std;
  6.  
  7. template <typename T> double sgn(T val) {
  8.     return double((T(0) < val) - (val < T(0)))/(val == val);
  9. }
  10. bool closeEnough(double LBD, double UBD, uint maxOrderDiff = 1, uint cutoffOrder = 1) {
  11.   double sgn_LBD = sgn(LBD);
  12.   double sgn_UBD = sgn(UBD);
  13.   double cutoff = pow(10, cutoffOrder);
  14.   double maxDiff = pow(10, maxOrderDiff);
  15.   if(sgn_LBD == sgn_UBD) {
  16.   	 bool test = -LBD<cutoff && UBD<cutoff; 
  17.   	 if(test) return test;
  18. 	 return LBD<UBD && abs(UBD)<abs(LBD)*maxDiff;
  19.   }
  20.   else if(sgn_UBD > 0) {
  21.   	return -LBD<cutoff && UBD<cutoff;
  22.   }
  23.   // if none of the above matches LBD >= UBD or any of the two is NAN
  24. }
  25.  
  26.  
  27. bool closeEnoughLog(double LBD, double UBD) {
  28.   double dist = 42;
  29.   double sgn_LBD = sgn(LBD);
  30.   double sgn_UBD = sgn(UBD);
  31.   if(sgn_LBD == sgn_UBD) {
  32.     if(LBD < UBD) { // central assumption!
  33.       dist = max(log10(abs(UBD)), 0.0) - max(log10(abs(LBD)), 0.0);
  34.       // We take max here because -10 < n < 10 is considered close enough!
  35.     }
  36.   }
  37.   else if(sgn_UBD > 0) { // LBD <= 0
  38.     dist = log10(-LBD) + log10(UBD); // can be negative but that's ok
  39.   }
  40.   // if none of the above matches LBD >= UBD or any of the two is NAN
  41.   return (dist < 1);
  42. }
  43.  
  44. int main() {
  45.   vector<double> LBD = {-INFINITY,-INFINITY,-100, -0.09, 0.09, NAN, -4, -2.4, 333, -40, -2.33};
  46.   vector<double> UBD = {+INFINITY, NAN,      100, 1,     1,    NAN, 0.02,   2.4,  231, 40, -0.023};
  47.   vector<uint> desired = {0,       0,        0,   1,     1,    0,   1,     1,    0,   0, 1 };
  48.   printf("%7s %7s %3s %6s %5s\n", "LBD", "UBD", "log", "simple", "check");
  49.   for(auto i(0); i < desired.size(); ++i) {
  50.   	printf("%7.2f %7.2f %3d %6d %5d\n", LBD[i], UBD[i], closeEnoughLog(LBD[i], UBD[i]), closeEnough(LBD[i], UBD[i]), desired[i] );
  51.   }
  52.  
  53.   return 0;
  54. }
Success #stdin #stdout 0s 15240KB
comments (?)
stdin 
Standard input is empty
stdout 
    LBD     UBD log simple check
   -inf     inf   0      0     0
   -inf     nan   0      0     0
-100.00  100.00   0      0     0
  -0.09    1.00   1      1     1
   0.09    1.00   1      1     1
    nan     nan   0      0     0
  -4.00    0.02   1      1     1
  -2.40    2.40   1      1     1
 333.00  231.00   0      0     0
 -40.00   40.00   0      0     0
  -2.33   -0.02   1      1     1
https://ideone.com/d1DSRX
language:
C++ (gcc 8.3)
created:
6 years ago
visibility:
public

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