Why would that be weird for there to be a difference? The more loops you have, the more computation time. Your java version is doing 256 additional iterations.
On Wed, May 6, 2015 at 11:34 AM, Vassilis Virvilis <vasv...@gmail.com> wrote: > Personal preference I guess... > > It looks more correct to me to have the initialization phase clearly > separated from the main loop. > > Do you think that something like that can create that difference? I have > been surprised in the past trying to understand where the computer spends > the time but that would be really - really weird, > > Vassilis > > On Wed, May 6, 2015 at 6:30 PM, JonL <j...@percsolutions.com> wrote: > >> Hmm.. in the Javascript version of the compress, you don't have a loop to >> initialize the "dict" like you do the map. It appears you are updating the >> "dict" during the same loop. While in the Java version, you have two >> loops. Why the slight difference in logic? >> >> On Wednesday, May 6, 2015 at 7:35:14 AM UTC-7, Vassilis Virvilis wrote: >>> >>> Anyway I profiled a bit. Here is the results >>> >>> compress total time: 721 >>> compress self: 203 ? What is it doing? The main loop probably >>> containsKey 180 (Map operation with jonL suggestion) >>> put 164 (Map) >>> append self 91 / total 119 (StringBuilder) >>> toString() 16 (StringBuilder) >>> valueOf 16 (convert dict_size++ to something in order to put it in >>> the map) >>> >>> The difference with the js version is around 200-250 msec. I can't >>> imagine where the next low hanging fruit would be. >>> >>> JonL after implementing __correctly__ your suggestion I was able to trim >>> 40-45 msec from the profile run (SDM). Unfortunately I cannot see that >>> improvement in the fully compiled version. >>> >>> >>> Vassilis >>> >>> On Wed, May 6, 2015 at 4:12 PM, Vassilis Virvilis <vas...@gmail.com> >>> wrote: >>> >>>> Hi Eric, >>>> >>>> I haven't use the JsArray because the compression algorithm requires >>>> map access and not list access. >>>> >>>> >>>> Vassilis >>>> >>>> >>>> On Wed, May 6, 2015 at 12:35 PM, Eric Ponthiaux <ponth...@sfeir.com> >>>> wrote: >>>> >>>>> Have you done any testing with JsArray or JsArrayOf ? >>>>> >>>>> >>>>> Le mardi 5 mai 2015 14:34:46 UTC+2, Vassilis Virvilis a écrit : >>>>>> >>>>>> Hi, >>>>>> >>>>>> At some point in time I needed to handle lzw >>>>>> compressing/uncompressing in the client so I found >>>>>> https://gist.github.com/revolunet/843889 >>>>>> >>>>>> Later on I rewrite the LZW in java. >>>>>> >>>>>> So I did. I benchmarked the difference and the new implementation was >>>>>> way slower when compressing. GWT/java is actually better when >>>>>> uncompressing. >>>>>> >>>>>> I changed the java collections to javascript collections JsMap, and >>>>>> JsList and the difference was greatly reduced but not enough to be able >>>>>> to >>>>>> scrap the js implementation. >>>>>> >>>>>> My guess any remaining gains are hidden in the StringBuilder but I >>>>>> may by wrong. >>>>>> >>>>>> Chrome >>>>>> Firefox IE >>>>>> Js 544/61 >>>>>> 626/78 795/171 >>>>>> Java 750/48 >>>>>> 1702/48 2401/468 >>>>>> JavaJsCollections 785/38 >>>>>> 1398/38 1877/351 >>>>>> >>>>>> The numbers are compressing/uncompressing >>>>>> 1000 iterations with a random string multiplied 10 times >>>>>> >>>>>> I am using a single permutation with collapse-all. Can this be the >>>>>> culprit? >>>>>> >>>>>> Any idea what to change in order to increase the performance in the >>>>>> java code? >>>>>> >>>>>> Here is the code >>>>>> >>>>>> >>>>>> package com.biovista.lib.gwt.client; >>>>>> >>>>>> import com.google.gwt.core.client.JavaScriptObject; >>>>>> >>>>>> public class Util { >>>>>> private static final char DICT_SIZE = 256; >>>>>> >>>>>> public static class JsMap<T> extends JavaScriptObject { >>>>>> protected JsMap() { >>>>>> } >>>>>> >>>>>> public final native void put(String key, T value) /*-{ >>>>>> this[key] = value; >>>>>> }-*/; >>>>>> >>>>>> public final native boolean containsKey(String key) /*-{ >>>>>> return (key in this); >>>>>> }-*/; >>>>>> >>>>>> public final native T get(String key) /*-{ >>>>>> return this[key]; >>>>>> }-*/; >>>>>> >>>>>> public static JsMap createInstance() { >>>>>> return (JsMap) createObject(); >>>>>> } >>>>>> } >>>>>> >>>>>> public static class JsList<T> extends JavaScriptObject { >>>>>> protected JsList() { >>>>>> } >>>>>> >>>>>> public final native void add(T value) /*-{ >>>>>> this.push(value); >>>>>> }-*/; >>>>>> >>>>>> public final native int size() /*-{ >>>>>> return this.length; >>>>>> }-*/; >>>>>> >>>>>> public final native T get(char index) /*-{ >>>>>> return this[index]; >>>>>> }-*/; >>>>>> >>>>>> public static JsList createInstance() { >>>>>> return (JsList) createArray(); >>>>>> } >>>>>> } >>>>>> >>>>>> public static String compressLZW(String text) { >>>>>> // Build the dictionary. >>>>>> // final Map<String, Character> map = new HashMap<String, >>>>>> Character>( >>>>>> // DICT_SIZE); >>>>>> final JsMap<Character> map = JsMap.createInstance(); >>>>>> for (char i = 0; i < DICT_SIZE; i++) { >>>>>> map.put("" + i, i); >>>>>> } >>>>>> >>>>>> char dict_size = DICT_SIZE; >>>>>> >>>>>> String w = ""; >>>>>> final StringBuilder result = new StringBuilder(); >>>>>> for (char c : text.toCharArray()) { >>>>>> final String wc = w + c; >>>>>> if (map.containsKey(wc)) >>>>>> w = wc; >>>>>> else { >>>>>> result.append(map.get(w)); >>>>>> // Add wc to the dictionary. >>>>>> map.put(wc, dict_size++); >>>>>> w = "" + c; >>>>>> } >>>>>> } >>>>>> >>>>>> // Output the code for w. >>>>>> if (!w.equals("")) >>>>>> result.append(map.get(w)); >>>>>> >>>>>> return result.toString(); >>>>>> } >>>>>> >>>>>> /** uncompress a string. */ >>>>>> public static String uncompressLZW(String compressed_text) { >>>>>> // Build the dictionary. >>>>>> // final List<String> rmap = new ArrayList<String>(DICT_SIZE); >>>>>> final JsList<String> rmap = JsList.createInstance(); >>>>>> for (char i = 0; i < DICT_SIZE; i++) { >>>>>> rmap.add("" + i); >>>>>> } >>>>>> final char[] compressed = compressed_text.toCharArray(); >>>>>> >>>>>> String w = "" + compressed[0]; >>>>>> final StringBuilder result = new StringBuilder(w); >>>>>> for (int i = 1; i < compressed.length; i++) { >>>>>> final char k = compressed[i]; >>>>>> final String entry = k < rmap.size() ? rmap.get(k) : w >>>>>> + w.charAt(0); >>>>>> result.append(entry); >>>>>> // Add w+entry[0] to the dictionary. >>>>>> rmap.add(w + entry.charAt(0)); >>>>>> w = entry; >>>>>> } >>>>>> return result.toString(); >>>>>> } >>>>>> >>>>>> // LZW-compress a string >>>>>> public static native String lzwCompress(String s) /*-{ >>>>>> var dict = {}; >>>>>> var data = (s + "").split(""); >>>>>> var out = []; >>>>>> var currChar; >>>>>> var phrase = data[0]; >>>>>> var code = 256; >>>>>> for (var i = 1; i < data.length; i++) { >>>>>> currChar = data[i]; >>>>>> if (dict[phrase + currChar] != null) { >>>>>> phrase += currChar; >>>>>> } else { >>>>>> out.push(phrase.length > 1 ? dict[phrase] : phrase >>>>>> .charCodeAt(0)); >>>>>> dict[phrase + currChar] = code; >>>>>> code++; >>>>>> phrase = currChar; >>>>>> } >>>>>> } >>>>>> out.push(phrase.length > 1 ? dict[phrase] : >>>>>> phrase.charCodeAt(0)); >>>>>> for (var i = 0; i < out.length; i++) { >>>>>> out[i] = String.fromCharCode(out[i]); >>>>>> } >>>>>> return out.join(""); >>>>>> }-*/; >>>>>> >>>>>> // Decompress an LZW-encoded string >>>>>> public static native String lzwDecompress(String s) /*-{ >>>>>> var dict = {}; >>>>>> var data = (s + "").split(""); >>>>>> var currChar = data[0]; >>>>>> var oldPhrase = currChar; >>>>>> var out = [ currChar ]; >>>>>> var code = 256; >>>>>> var phrase; >>>>>> for (var i = 1; i < data.length; i++) { >>>>>> var currCode = data[i].charCodeAt(0); >>>>>> if (currCode < 256) { >>>>>> phrase = data[i]; >>>>>> } else { >>>>>> phrase = dict[currCode] ? dict[currCode] >>>>>> : (oldPhrase + currChar); >>>>>> } >>>>>> out.push(phrase); >>>>>> currChar = phrase.charAt(0); >>>>>> dict[code] = oldPhrase + currChar; >>>>>> code++; >>>>>> oldPhrase = phrase; >>>>>> } >>>>>> return out.join(""); >>>>>> }-*/; >>>>>> >>>>>> public static void benchmark() { >>>>>> final int N = 1000; >>>>>> final int M = 10; >>>>>> final String test1 = "opaopaopaopa236747862348 hfjsgfhjsd >>>>>> g4782q65 87324658764 8 37g fj hdshfjdhjsb hjsgfbhjgb hjdf sjjhsgd 87345y >>>>>> 783256 8736 8573587 68327563"; >>>>>> String test = ""; >>>>>> for (int i = 0; i < M; i++) { >>>>>> test += test1; >>>>>> } >>>>>> >>>>>> // log.info("old compress " + lzwCompress(test)); >>>>>> // log.info("new compress " + compressLZW(test)); >>>>>> // log.info("old uncompress " + >>>>>> lzwDecompress(lzwCompress(test))); >>>>>> // log.info("new uncompress " + >>>>>> uncompressLZW(compressLZW(test))); >>>>>> long t1 = System.currentTimeMillis(); >>>>>> for (int i = 0; i < N; i++) { >>>>>> lzwCompress(test); >>>>>> } >>>>>> long t2 = System.currentTimeMillis(); >>>>>> for (int i = 0; i < N; i++) { >>>>>> compressLZW(test); >>>>>> } >>>>>> long t3 = System.currentTimeMillis(); >>>>>> log.info("Compressing: old " + (t2 - t1) + " vs new " + (t3 >>>>>> - t2)); >>>>>> >>>>>> final String test_c = compressLZW(test); >>>>>> t1 = System.currentTimeMillis(); >>>>>> for (int i = 0; i < N; i++) { >>>>>> lzwDecompress(test_c); >>>>>> } >>>>>> t2 = System.currentTimeMillis(); >>>>>> for (int i = 0; i < N; i++) { >>>>>> uncompressLZW(test_c); >>>>>> } >>>>>> t3 = System.currentTimeMillis(); >>>>>> log.info("UnCompressing: old " + (t2 - t1) + " vs new " + >>>>>> (t3 - t2)); >>>>>> >>>>>> if (!(lzwDecompress(lzwCompress(test)).equals(test))) { >>>>>> log.error("old failure"); >>>>>> } >>>>>> >>>>>> if (!(uncompressLZW(compressLZW(test)).equals(test))) { >>>>>> log.error("new failure"); >>>>>> } >>>>>> } >>>>>> } >>>>>> >>>>>> >>>>>> -- >>>>>> Vassilis Virvilis >>>>>> >>>>> -- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "Google Web Toolkit" group. >>>>> To unsubscribe from this group and stop receiving emails from it, send >>>>> an email to google-web-toolkit+unsubscr...@googlegroups.com. >>>>> To post to this group, send email to google-we...@googlegroups.com. >>>>> Visit this group at http://groups.google.com/group/google-web-toolkit. >>>>> For more options, visit https://groups.google.com/d/optout. >>>>> >>>> >>>> >>>> >>>> -- >>>> Vassilis Virvilis >>>> >>> >>> >>> >>> -- >>> Vassilis Virvilis >>> >> -- >> You received this message because you are subscribed to the Google Groups >> "Google Web Toolkit" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to google-web-toolkit+unsubscr...@googlegroups.com. >> To post to this group, send email to google-web-toolkit@googlegroups.com. >> Visit this group at http://groups.google.com/group/google-web-toolkit. >> For more options, visit https://groups.google.com/d/optout. >> > > > > -- > Vassilis Virvilis > > -- > You received this message because you are subscribed to a topic in the > Google Groups "Google Web Toolkit" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/google-web-toolkit/XKQRRaPgkw0/unsubscribe > . > To unsubscribe from this group and all its topics, send an email to > google-web-toolkit+unsubscr...@googlegroups.com. > To post to this group, send email to google-web-toolkit@googlegroups.com. > Visit this group at http://groups.google.com/group/google-web-toolkit. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. 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