NormalizeDouble() not always rounding

[afiverestatcastle]

The NormalizeDouble function almost always rounds to 4 places, but every once in a while I get (ROC is: 0.0005999999999999999) some non-rounded number.

Can someone enlighten me why this is and how to fix?

Thanks.

void OnTick()
  {
    
      double Price1 = iClose("USDCHF",1,1);
      double Price2 = iClose("USDCHF",1,2);
     
      double ROC;
    
      
      if(Price1 > Price2) {
        ROC = Price1 - Price2;
      }
            
      if(Price1 < Price2) {
         ROC = Price2 - Price1;
      }
      
      
      double  ROC_Rounded = NormalizeDouble(ROC, 4);
         
     
      Comment("ROC is: ", ROC_Rounded);
  }

[Taras Slobodyanik]

afiverestatcastle:

The NormalizeDouble function almost always rounds to 4 places, but every once in a while I get (ROC is: 0.0005999999999999999) some non-rounded number.

Can someone enlighten me why this is and how to fix?

Thanks.

Try this

Comment("ROC is: ", NormalizeDouble(ROC_Rounded,4));

some fractional numbers cannot be accurately stored on a computer.

[Genesis Hafalla]

#include <stdlib.mqh>




void OnTick()
  {
    
      double Price1 = iClose("USDCHF",1,1);
      double Price2 = iClose("USDCHF",1,2);
     
      double ROC;
    
      
      if(Price1 > Price2) {
        ROC = Price1 - Price2;
      }
            
      if(Price1 < Price2) {
         ROC = Price2 - Price1;
      }
      
      
      double  ROC_Rounded = NormalizeDouble(ROC, 4);
         
     
      Comment("ROC is: ", DoubleToStrMorePrecision(ROC_Rounded,4));
  }

this will solve your issue. :)

[William Roeder]

afiverestatcastle: The NormalizeDouble function almost always rounds to 4 places, 

1. No it does not. It rounds to the digits specifies and returns a double. Floating point has infinite number of decimals, it's your not understanding floating point and that some numbers can't be represented exactly. (like 1/10.)
   

             Double-precision floating-point format - Wikipedia, the free encyclopedia

   See also The == operand. - MQL4 programming forum

   Print out your values to the precision you want with DoubleToString - Conversion Functions - MQL4 Reference.

2. You used NormalizeDouble, It's use is usually wrong, as it is in your case.
   • SL/ TP(stops) need to be normalized to tick size (not Point.) (On 5Digit Broker Stops are only allowed to be placed on full pip values. How to find out in mql? - MQL4 programming forum) and abide by the limits Requirements and Limitations in Making Trades - Appendixes - MQL4 Tutorial and that requires understanding floating point equality Can price != price ? - MQL4 programming forum
   • Open price for pending orders need to be adjusted. On Currencies, Point == TickSize, so you will get the same answer, but it won't work on Metals. So do it right: Trailing Bar Entry EA- MQL4 programming forum or Bid/Ask: (No Need) to use NormalizeDouble in OrderSend - MQL4 programming forum
   • Lot size must also be adjusted to a multiple of LotStep and check against min and max. If that is not a power of 1/10 then NormalizeDouble is wrong. Do it right.
   • MathRound() and NormalizeDouble() are rounding in a different way. Make it explicit.
               MT4:NormalizeDouble - General - MQL5 programming forum
               How to Normalize - Expert Advisors and Automated Trading - MQL5 programming forum

[amrali]

afiverestatcastle:

The NormalizeDouble function almost always rounds to 4 places, but every once in a while I get (ROC is: 0.0005999999999999999) some non-rounded number.

Can someone enlighten me why this is and how to fix?

Thanks.

This is the way how 0.0006 is represented internally in memory. Try this code:

Print(0.0006);  // 0.0005999999999999

The solution for your code is:

Print(DoubleToString(0.0006,4)) //0.0006

The above problem is not related to NormalizeDouble() or MathRound() in any way.

[Alexander Fedosov]

amrali:

This is the way how 0.0006 is represented internally in memory. Try this code:

The solution for your code is:

The above problem is not related to NormalizeDouble() or MathRound() in any way.

DoubleToString good just for Print. 

[afiverestatcastle]

Thanks you all for your help.

I will need a few days to study all of your comments.

[Genesis Hafalla]

afiverestatcastle:

Thanks you all for your help.

I will need a few days to study all of your comments.

Just use this to save your time

Comment("ROC is: ", DoubleToStrMorePrecision(ROC_Rounded,4));
  

[Julius Mwangi Maina]

what about when i am normalising lotsizes, take profit and stop losses? In this case i cant use strings (DoubleToString)..!

[Keith Watford]

Julius Mwangi:

what about when i am normalising lotsizes, take profit and stop losses? In this case i cant use strings (DoubleToString)..!

You only use DoubleToString to print, not in calculations.

[Julius Mwangi Maina]

Keith Watford:

You only use DoubleToString to print, not in calculations.

Thanks a lot. Well understood