thomasmueller / minperf Goto Github PK

Hi, I'm not sure what's the best place to ask questions related to this project, so I hope it's ok if I create this issue to do so.

I'm wondering whether you did any performance comparisons (in regards to look-up speed) to the JDK's HashMap. In a quick test I'm observing that HashMap is about 8x faster for get() than calling RecSplitEvaluator#eval(). Does this match your expectation, too, or am I doing some stupid mistake on my end?

I'm interested as I was hoping to use MinPerf as means to optimize through-put of look-ups in immutable maps I have; but perhaps I was misguided, and actually optimizing throughput isn't a goal for MinPerf, but it's (only) optimizing for space instead? In my case, space is not so much of an issue (maps are 10K entries at most), but accessing them as efficiently as possible is desirable. Thanks a lot for clarifying!

Looking here:

Also, I have a list of parameters for different hash lengths here if you need it:
https://github.com/sh1boot/prpg/blob/e2d0a1c66359348c510819fb004b27e6f181499e/prpg.c#L104

thanks

Does this data structure retain the keys used to create it? I am searching for a perfect hash map to avoid storing millions of string keys of about 250 characters in length that map to relatively small integers. I found this one, but it seems to keep the keys and do an equality check on lookup: https://github.com/haifengl/smile/blob/f597591d0b26d14dbeaa2fdc2b70b1448ee3c564/math/src/main/java/smile/hash/PerfectHash.java.

I would like to test the minperf API but when I clone the project and open it, I have an error like Some @param values cannot be converted to target type: "CUCKOO8_4" cannot be converted to org.minperf.bloom.Filter.Type.
Please, How to solve this problem and compile the API?

I tried to execute this code and I got java.lang.ArrayIndexOutOfBoundsException

`
@org.junit.Test
public void test() {

    Builder builder = new Builder();

    long[] ls = new long[]{10, 20, 50};

    BitBuffer bb = builder.generate(ls);
    FastEvaluator evaluator = builder.evaluator(bb);

    for (long l : ls) {
        System.out.println(l + " -> " + evaluator.evaluate(l));
    }

}`

Is there an error in my code?

This is the full exception trace :
java.lang.ArrayIndexOutOfBoundsException: 1 at org.minperf.BitBuffer.readBit(BitBuffer.java:130) at org.minperf.BitBuffer.readEliasDelta(BitBuffer.java:264) at org.minperf.hem.recsplit.FastEvaluator.<init>(FastEvaluator.java:19) at org.minperf.hem.recsplit.Builder.evaluator(Builder.java:34) at net.almightshell.experiments.Test.compareSpace(Test.java:26) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at org.apache.maven.surefire.junit4.JUnit4TestSet.execute(JUnit4TestSet.java:53) at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:123) at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:104) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.maven.surefire.util.ReflectionUtils.invokeMethodWithArray(ReflectionUtils.java:164) at org.apache.maven.surefire.booter.ProviderFactory$ProviderProxy.invoke(ProviderFactory.java:110) at org.apache.maven.surefire.booter.SurefireStarter.invokeProvider(SurefireStarter.java:175) at org.apache.maven.surefire.booter.SurefireStarter.runSuitesInProcessWhenForked(SurefireStarter.java:107) at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:68)