ptrhash-paper: bucket-fn construction results

posts/ptrhash-paper/plot.py → posts/ptrhash-paper/bucket-fn.py

@@ -41,12 +41,15 @@ def invert(f, y):
     return l
 
 
+lmbda = 4
+
+
 def bucket_sz(f, y):
     y1 = y
     y2 = y + 0.001
     x1 = invert(f, y1)
     x2 = invert(f, y2)
-    return (x2 - x1) * 1000
+    return lmbda * (x2 - x1) * 1000
 
 
 xs = [x / 1000 for x in range(1000)]
@@ -73,7 +76,7 @@ def bucket_sz(f, y):
 # Add horizontal grid lines
 plt.grid(axis="y", lw=0.5)
 
-plt.savefig("bucket-fn.svg", bbox_inches="tight")
+plt.savefig("plots/bucket-fn.svg", bbox_inches="tight")
 plt.close()
 
 ## PLOT 2
@@ -93,11 +96,14 @@ def bucket_sz(f, y):
 plt.gca().spines["right"].set_visible(False)
 # x and y from 0 to 1
 plt.xlim(0, 1)
-plt.ylim(0, 3)
+plt.ylim(0, 11.5)
 plt.xlabel("Normalized bucket index")
-plt.ylabel("Relative expected bucket size")
+plt.ylabel("Expected bucket size for $\lambda = 4$")
 # Add horizontal grid lines
-plt.grid(axis="y", lw=0.5)
+plt.grid(axis="y", lw=0.5, which="major")
+plt.grid(axis="y", lw=0.5, which="minor", alpha=0.4)
+# Add minor tickes lines every 1
+plt.yticks(range(0, 12, 1), minor=True)
 
-plt.savefig("bucket-size.svg", bbox_inches="tight")
+plt.savefig("plots/bucket-size.svg", bbox_inches="tight")
 plt.close()

posts/ptrhash-paper/evals.py

@@ -0,0 +1,118 @@
+#!/usr/bin/env python3
+
+import json
+from math import log, floor, ceil
+import matplotlib.pyplot as plt
+from matplotlib.ticker import MultipleLocator
+
+
+def build_stats(f, out):
+    alpha = 0.98
+
+    with open(f) as f:
+        all_data = json.load(f)
+
+    cols = len(all_data)
+
+    pcts = range(100)
+    xs = [x / 100 for x in range(0, 101)]
+
+    # Figure with 3 subplots
+    fig, axs = plt.subplots(
+        1, cols, figsize=(cols * 3 + 0.75, 2.5), layout="constrained"
+    )
+    if cols == 1:
+        axs = [axs]
+    keys = ["linear", "skewed", "optimal", "square", "cubic"]
+    keys = [k for k in keys if k in all_data]
+
+    for ax1, name in zip(axs, keys):
+        data = all_data[name]["by_pct"]
+        elem = 0
+        elems = [0]
+        for pct in pcts:
+            elem += data[pct]["elements"]
+            elems.append(elem)
+        slots = elems[-1] / alpha
+        load = [x / slots for x in elems]
+
+        # Set plot size
+        ax3 = ax1.twinx()
+        ax2 = ax1.twinx()
+
+        ax1.set_ylim(0, 1.0)
+        ax3.set_ylim(0, 1)
+        ax2.set_ylim(0, 10)
+
+        ax1.set_title(name.capitalize())
+
+        ax1.set_xlabel("Normalized bucket index")
+        ax1.set_ylabel("Evictions per bucket")
+        ax2.set_ylabel("Bucket size")
+        ax2.yaxis.label.set_color("red")
+        ax1.xaxis.set_minor_locator(MultipleLocator(0.1))
+
+        p1 = ax1.plot(
+            xs[1:],
+            [data[pct]["evictions"] / data[pct]["buckets"] for pct in pcts],
+            label="Evictions per bucket",
+            color="black",
+        )
+        # Plot load factor
+        p3 = ax3.fill(xs + [1], load + [0], color="red", alpha=0.1, label="Load factor")
+        ax3.yaxis.set_visible(False)
+
+        # Plot bucket size on secondary axis
+        p2 = ax2.plot(
+            xs[1:],
+            [data[pct]["elements"] / data[pct]["buckets"] for pct in pcts],
+            color="red",
+            label="Bucket size",
+        )
+
+        ax1.set_zorder(ax3.get_zorder() + 1)
+        ax1.set_frame_on(False)
+
+        # Only show x and y ax
+        ax1.spines["top"].set_visible(False)
+        ax1.spines["bottom"].set_visible(False)
+        ax1.spines["left"].set_visible(False)
+        ax1.spines["right"].set_visible(False)
+        ax2.spines["top"].set_visible(False)
+        ax2.spines["bottom"].set_visible(False)
+        ax2.spines["left"].set_visible(False)
+        ax2.spines["right"].set_visible(False)
+        ax3.spines["top"].set_visible(False)
+        ax3.spines["bottom"].set_visible(False)
+        ax3.spines["left"].set_visible(False)
+        ax3.spines["right"].set_visible(False)
+        # x and y from 0 to 1
+        ax1.set_xlim(0, 1)
+        # plt.ylim(0, 1)
+        # plt.xlabel("Normalized hash")
+        # plt.ylabel("Normalized bucket index")
+        # Add horizontal grid lines
+        ax1.grid(axis="y", lw=0.5)
+
+        # Keep only leftmost and rightmost y-axis
+        # First
+        if name == keys[0]:
+            ax1.yaxis.set_visible(True)
+        else:
+            ax1.set_yticklabels([])
+            ax1.yaxis.set_ticks_position("none")
+            ax1.set_ylabel(None)
+        # Last
+        if name == keys[-1]:
+            ax2.yaxis.set_visible(True)
+            if len(keys) > 1:
+                ax1.legend(handles=p1 + p2 + p3, loc="best")
+        else:
+            ax2.yaxis.set_visible(False)
+
+    plt.savefig(out, bbox_inches="tight")
+    plt.close()
+
+
+build_stats("data/build_stats_l35.json", "plots/build_stats_l35.svg")
+build_stats("data/build_stats_l40.json", "plots/build_stats_l40.svg")