Array Archives - The Curious Consultant

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Does caching calculated loop indexes make a difference?

Posted on August 3, 2020 by David Lozinski

Does caching calculated loop indexes make a difference? Recently I was reviewing code to a real time financial application. Within a major for-loop construct, I came across the following subset of C# code:

for (int index = 1; index < maxLoops; index++)
{
	//Did some stuff

	_iSeries1[index] = _coeff1*MarketSeries.Close[index] + _coeff2*_iSeries1[index - 1];
	_iSeries2[index] = _coeff1*_iSeries1[index] + _coeff2*_iSeries2[index - 1];
	_iSeries3[index] = _coeff1*_iSeries2[index] + _coeff2*_iSeries3[index - 1];
	_iSeries4[index] = _coeff1*_iSeries3[index] + _coeff2*_iSeries4[index - 1];
	_iSeries5[index] = _coeff1*_iSeries4[index] + _coeff2*_iSeries5[index - 1];
	_iSeries6[index] = _coeff1*_iSeries5[index] + _coeff2*_iSeries6[index - 1];

	//Did more stuff in which objects and arrays were frequently accessed with [index - 1]
}

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for (int index = 1; index < maxLoops; index++)

{

//Did some stuff

_iSeries1[index] = _coeff1*MarketSeries.Close[index] + _coeff2*_iSeries1[index - 1];

_iSeries2[index] = _coeff1*_iSeries1[index] + _coeff2*_iSeries2[index - 1];

_iSeries3[index] = _coeff1*_iSeries2[index] + _coeff2*_iSeries3[index - 1];

_iSeries4[index] = _coeff1*_iSeries3[index] + _coeff2*_iSeries4[index - 1];

_iSeries5[index] = _coeff1*_iSeries4[index] + _coeff2*_iSeries5[index - 1];

_iSeries6[index] = _coeff1*_iSeries5[index] + _coeff2*_iSeries6[index - 1];

//Did more stuff in which objects and arrays were frequently accessed with [index - 1]

}

Look how many times [index… Continue Reading →

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Length Vs Count Vs Initialized Variable in C#

Posted on February 10, 2020 by David Lozinski

Length Vs Count Vs Initialized Variable in C# This test originated from having to loop over millions of records in an array in an application that requires everything be as fast as possible. It was stumbled upon by accident when… Continue Reading →

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C# .Net: Fastest Way to Clear Collections

Posted on June 18, 2014 by David Lozinski

C# .Net: Fastest Way to clear Collections In this article I’ll investigate different ways to clear out commonly used Collections such as Hashsets, Dictionaries, ConcurrentDictionaries, ArrayLists, and Arrays, benchmarking the results. This will determine in C# .Net: Fastest way to… Continue Reading →