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add comments on compression #1119

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Jul 26, 2021
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add comments on compression #1119

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14 changes: 14 additions & 0 deletions fastfield_codecs/src/multilinearinterpol.rs
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@@ -1,3 +1,17 @@
/*!

MultiLinearInterpol compressor uses linear interpolation to guess a values and stores the offset, but in blocks of 512.

With a CHUNK_SIZE of 512 and 29 byte metadata per block, we get a overhead for metadata of 232 / 512 = 0,45 bits per element.
The additional space required per element in a block is the the maximum deviation of the linear interpolation estimation function.

E.g. if the maximum deviation of an element is 12, all elements cost 4bits.

Size per block:
Num Elements * Maximum Deviation from Interpolation + 29 Byte Metadata

*/

use crate::FastFieldCodecReader;
use crate::FastFieldCodecSerializer;
use crate::FastFieldDataAccess;
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