cache_prob_fpi.h File Reference

Cache hit and miss probabilities from the fixed-point multipliers. More...

#include <cstddef>
#include <vector>
#include "line/api/cache/cache_xi_fp.h"
#include "line/num/number.h"
#include "line/util/error.h"
#include "line/util/matrix.h"

Include dependency graph for cache_prob_fpi.h:

Go to the source code of this file.

Namespaces
namespace	line
namespace	line::cache

Functions
template<class T>
Matrix< T >	line::cache::cache_prob_fpi (const Matrix< T > &gamma, const std::vector< int > &m)
	Cache hit and miss probabilities from the fixed-point multipliers.

Detailed Description

Cache hit and miss probabilities from the fixed-point multipliers.

Templated port of matlab/src/api/cache/cache_prob_fpi.m, cross-checked against jar/src/main/java/jline/api/cache/Cache_prob_fpi.java.

With S(i) = sum_l gamma(i,l) xi(l) from cache_xi_fp,

prob(i,1) = 1 / (1 + S(i)) (miss) prob(i,1+l) = S(i) / (1 + S(i)) (hit, as written by the references)

ARITHMETIC: transcendental, inherited from cache_xi_fp's tolerance-stopped iteration.

REFERENCE DEFECT (both codebases): the hit entry is the AGGREGATE hit probability S/(1+S), written identically into all h list columns, instead of the per-list gamma(i,l) xi(l)/(1+S(i)). MATLAB's prob(i,2:(1+h)) = gamma(i,:)*xi(:) ./ (1+gamma(i,:)*xi(:)) is a scalar broadcast over the row, and the JAR reproduces it with an explicit loop that stores the same mul.get(0) in every column. The consequence is that the row sums to 1 + (h-1) S/(1+S), not to 1, whenever h > 1; only h == 1 is correct. This port is faithful to the references – correcting it here would silently diverge from MATLAB and the JAR – and the conservation test in the suite is asserted only for h == 1 for exactly this reason.

Definition in file cache_prob_fpi.h.