diff --git a/c/enc/block_splitter_inc.h b/c/enc/block_splitter_inc.h index bf62358..7e96204 100644 --- a/c/enc/block_splitter_inc.h +++ b/c/enc/block_splitter_inc.h @@ -118,6 +118,7 @@ static size_t FN(FindBlocks)(const DataType* data, const size_t length, size_t insert_cost_ix = symbol * num_histograms; double min_cost = 1e99; double block_switch_cost = block_switch_bitcost; + static const double threshold = 0.07 / 2000.0; size_t k; for (k = 0; k < num_histograms; ++k) { /* We are coding the symbol with entropy code k. */ @@ -129,7 +130,7 @@ static size_t FN(FindBlocks)(const DataType* data, const size_t length, } /* More blocks for the beginning. */ if (byte_ix < 2000) { - block_switch_cost *= 0.77 + 0.000035 * (double)byte_ix; + block_switch_cost *= 0.77 + threshold * (double)byte_ix; } for (k = 0; k < num_histograms; ++k) { cost[k] -= min_cost; diff --git a/c/enc/literal_cost.c b/c/enc/literal_cost.c index fafc7f6..b063afc 100644 --- a/c/enc/literal_cost.c +++ b/c/enc/literal_cost.c @@ -106,6 +106,7 @@ static void EstimateBitCostsForLiteralsUTF8(size_t pos, size_t len, size_t mask, size_t utf8_pos = UTF8Position(last_c, c, max_utf8); size_t masked_pos = (pos + i) & mask; size_t histo = histogram[256 * utf8_pos + data[masked_pos]]; + static const double threshold = 0.35 / 2000.0; double lit_cost; if (histo == 0) { histo = 1; @@ -121,7 +122,7 @@ static void EstimateBitCostsForLiteralsUTF8(size_t pos, size_t len, size_t mask, rapidly in the beginning of the file, perhaps because the beginning of the data is a statistical "anomaly". */ if (i < 2000) { - lit_cost += 0.7 - ((double)(2000 - i) * 0.000175); + lit_cost += 0.7 - ((double)(2000 - i) * threshold); } cost[i] = (float)lit_cost; }