Intel® Integrated Performance Primitives
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ScaleFactor!

mickeyhah
Beginner
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Hallo,

I know that my question is a little bit silly but till now I can not understand what happened here?

In file ippiman.pdf page 55, I found this one

The following example shows how the precision can be partially retained by means of scaling.The integer square root operation

ippiSqrt (without scaling) for the input value 2 gives the result equal to 1 instead of 1.414. Scaling of the internally computed output value with the factor scaleFactor = -3 gives the result 11, and permits to restore the more precise value as 11*2^-3=1.375.

I didn't understand the bold line, where does "11" come from? Why do we have 11 but not another number?

Thank you very much for any help.

Best,

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mickeyhah
Beginner
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Hi,

Thank you very much for your reply, I have another question about scaleFactor. There are many functions that have scaleFactor, if I don't want to use it, just set itequal 0. Is it right?

Thank you again

Regards

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