Several Divide by zero exceptions

[pahlot]

Hi,

Working against 3.1;

after much digging I have found that if a price hasn't moved within a given period of time the CCI will cause a DivideByZero exception @ line 29 because the mean deviation is 0.

To reproduce:
`[TestMethod]
public void Expect_CCI_Exception()
{
var candles = new List();
for(int i = 0; i <= 100; i++)
{
candles.Add(new Candle()
{
Open = 0.03m,
Close = 0.03m
});
}
Assert.ThrowsException(() => candles.Cci(20));

    }`

[pahlot]

Same with the ADX. Still tracing the source of that one...

[TestMethod] public void Expect_ADX_Exception() { var candles = new List<Candle>(); for (int i = 0; i <= 100; i++) { candles.Add(new Candle() { Open = 0.03m, Close = 0.03m }); } Assert.ThrowsException<DivideByZeroException>(() => candles.Adx(20)); }

[pahlot]

And DMI

[TestMethod] public void Expect_DMI_Exception() { var candles = new List<Candle>(); for (int i = 0; i <= 100; i++) { candles.Add(new Candle() { Open = 0.03m, Close = 0.03m }); } Assert.ThrowsException<DivideByZeroException>(() => candles.Dmi(20)); }

[pahlot]

I dare say there may be others, but I am running out of time as I am about to go away for work.

Could refactor any divisions to something like;

static public decimal SafeDivision(this decimal numerator, decimal denominator) { (numerator == 0) ?? return 0; return (denominator == 0) ? 0 : numerator / denominator; }

[karlwancl]

@pahlot thanks for pointing out. I need some time to check all the indicator for the division.

[pahlot]

@lppkarl that's understandable. I was thinking about how to best test this along with expending on how we can use the indicators.

I haven't got the time in the next few weeks but what I was thinking is to have a mechanism of discovery of and registration of indicators.

something (very roughly like);

IDiscoverableIndcator { string Key => $"nameOf(theIndecator)_{ConfigValue}"; string FriendlyName; int DefaultConfigValue = 20; int ConfigValue = 20; }

And then a discovery service to list each. This will allow us to have a common discoverable interface for custom implementations, and also register an indicator with a custom config value.

So we could have something like;

indicator.GetByName(name);
indicator.GetInstancesOf();

etc

This would then also allow us to run any new indicators against a common test, such as making sure there is no DivideByZero issue in one foul swoop.

Just an idea.

[karlwancl]

@pahlot Thanks for the idea, but i just want to make something clear. Do you mean we introduce an IDiscoverableIndicator, and make all Analyzables (the base of all indicators) implement this, and we create a test case to discover all these indicators and test the case? I am a bit confuse.