ArrayBSearch....Baffling??

[sd59]

I have a 101 element array (shown):

  ArrayResize(Array,count);
  ArraySort(Array,WHOLE_ARRAY,0,MODE_ASCEND);
  int c = ArrayBsearch(Array,NormalizeDouble(1.6124,4),WHOLE_ARRAY,0,MODE_ASCEND);
  Print(c):
c = 78???

  ArrayResize(Array,count);
  ArraySort(Array,WHOLE_ARRAY,0,MODE_ASCEND);
  int c = ArrayBsearch(Array,NormalizeDouble(1.5828,4),WHOLE_ARRAY,0,MODE_ASCEND);
  Print(c):
c = 4??

Please can anyone tell me what is happening? 

Shouldn't it search for the value being asked for and return the correct index?

thanks

[Simon Gniadkowski]

sd59:

I have a 101 element array (shown):

I'm guessing you simply used Print() to show the values in your array ? I'm also guessing you have 5 digits in your data not 4 ? use Print() with DoubleToStr(value, Digits) and show the values in the array again, then read the documentation for ArrayBsearch() and it should make sense . . .

[sd59]

sd59:

I have a 101 element array (shown):

her's my code now:

ArrayResize(Array,count);
  ArraySort(Array,WHOLE_ARRAY,0,MODE_ASCEND);
  for(int x=0;x<count;x++)Print(x,"  ",DoubleToStr(BendArray[x],5));
  int c = ArrayBsearch(Array,NormalizeDouble(1.60349,5),WHOLE_ARRAY,0,MODE_ASCEND);
  Print(DoubleToStr(c,0));

I won't list the whole array again just snippets. So using the example above c = 59.

I can go on with other examples but the result is the same. Sometimes (rarely) it will get the right index - it's all very erratic.

[Simon Gniadkowski]

sd59:

her's my code now:

I won't list the whole array again just snippets. So using the example above c = 59.

I can go on with other examples but the result is the same. Sometimes (rarely) it will get the right index - it's all very erratic.

Maybe it's a double comparison issue, maybe 1.60349 in cell 60 is fractionally greater than 1.60349 so the nearest lower value is found instead, cell 59

You could try this modification . . .

double HalfAPoint = Point / 2.0;    //  <--- added

ArrayResize(Array,count);
  ArraySort(Array,WHOLE_ARRAY,0,MODE_ASCEND);
  for(int x=0;x<count;x++)Print(x,"  ",DoubleToStr(BendArray[x],5));
  int c = ArrayBsearch(Array, 1.60349 + HalfAPoint, WHOLE_ARRAY,0,MODE_ASCEND);  // <--- modified
  Print(DoubleToStr(c,0));

[sd59]

To go a step further I changed everything to 8 digit precision.

ArrayResize(Array,count);
  ArraySort(Array,WHOLE_ARRAY,0,MODE_ASCEND);
  for(int x=0;x<count;x++)Print(x,"  ",DoubleToStr(BendArray[x],8));
  int c = ArrayBsearch(Array,NormalizeDouble(1.60156250,8),WHOLE_ARRAY,0,MODE_ASCEND);
  Print(DoubleToStr(c,0));

with example above c = 52!!

I thought it was going to work first of all because the first few tests were correct. Then the above happened...

If this is real it's not good!

[Alain Verleyen]

How is your array "Array" filled with values ?

[sd59]

int count = 0;

for(int j=0;j<=Bars;j++)
{
 if(...condition met....)
  {
   Array[count] = iHigh(NULL,Period_H4,j);
   count++;
  }
}

[Simon Gniadkowski]

RaptorUK:

Maybe it's a double comparison issue, maybe 1.60349 in cell 60 is fractionally greater than 1.60349 so the nearest lower value is found instead, cell 59

You could try this modification . . .

Sorry, my mistake, the modification should of course be . . .

  int c = ArrayBsearch(Array, 1.60349  -  HalfAPoint, WHOLE_ARRAY,0,MODE_ASCEND);  // <--- modified

[sd59]

But isn't using 8 digit precision the ultimate test?

[Simon Gniadkowski]

sd59:
But isn't using 8 digit precision the ultimate test?

Nope, not if it's a double comparison issue . . . what I am suggesting is a work around and if it works it suggests there is a bug with ArrayBsearch() with double array types.

[Alain Verleyen]

sd59:

Try this (not tested) :

int count = 0;

for(int j=0;j<=Bars;j++)
{
 if(...condition met....)
  {
   Array[count] = NormalizeDouble(iHigh(NULL,Period_H4,j),Digits);
   count++;
  }
}

and then

  ArrayResize(Array,count);
  ArraySort(Array,WHOLE_ARRAY,0,MODE_ASCEND);
  for(int x=0;x<count;x++)Print(x,"  ",DoubleToStr(BendArray[x],8));
  int c = ArrayBsearch(Array,NormalizeDouble(1.60156250,Digits),WHOLE_ARRAY,0,MODE_ASCEND);