Changeset 166462 in webkit

Timestamp:

Mar 30, 2014 9:53:53 AM (10 years ago)

Author:

mark.lam@apple.com

Message:

LongSpider 3d-morph result check is inappropriate.
<​https://webkit.org/b/130928>

Reviewed by Filip Pizlo.

The LongSpider 3d-morph component expected result check is incorrect.
The existing test checks if the leading digit of a sum starts with "-1".
However, it turned out that the expected sum is in the order of
-1.8735013540549517e-16 (i.e. very close to 0). With small errors in
the terms of the sum adding up, it is very easy for the resultant sum
to fluctuate. There is no guarantee that the resultant sum's most
significant digit will start with -1 either.

The fix is to do a tolerance check on all the terms of the sum as well
as the total sum value instead. The tolerance should be more lenient
for the sum which accumulates error from the individual terms, then for
individual terms.

• LongSpider/3d-morph.js:

(expect):

Location:

trunk/PerformanceTests

Files:

• ChangeLog (modified) (1 diff)
• LongSpider/3d-morph.js (modified) (2 diffs)

trunk/PerformanceTests/ChangeLog

@@ +1 @@
+2014-03-29  Mark Lam  <mark.lam@apple.com>
+
+        LongSpider 3d-morph result check is inappropriate.
+        <https://webkit.org/b/130928>
+
+        Reviewed by Filip Pizlo.
+
+        The LongSpider 3d-morph component expected result check is incorrect.
+        The existing test checks if the leading digit of a sum starts with "-1".
+        However, it turned out that the expected sum is in the order of
+        -1.8735013540549517e-16 (i.e. very close to 0).  With small errors in
+        the terms of the sum adding up, it is very easy for the resultant sum 
+        to fluctuate.  There is no guarantee that the resultant sum's most
+        significant digit will start with -1 either.
+
+        The fix is to do a tolerance check on all the terms of the sum as well
+        as the total sum value instead.  The tolerance should be more lenient
+        for the sum which accumulates error from the individual terms, then for
+        individual terms.
+
+        * LongSpider/3d-morph.js:
+        (expect):
+
 2014-03-28  Zoltan Horvath  <zoltan@webkit.org>
 

trunk/PerformanceTests/LongSpider/3d-morph.js

@@ -49 +49 @@
 }
 
-testOutput = 0;
-for (var i = 0; i < nx; i++)
-    testOutput += a[3*(i*nx+i)+1];
-a = null;
-
 // This has to be an approximate test since ECMAscript doesn't formally specify
 // what sin() returns. Even if it did specify something like for example what Java 7
@@ -59 +54 @@
 // would not be able to do an exact test here since that would allow for just enough
 // low-bit slop to create possibly big errors due to testOutput being a sum.
-var expected = "-1";
-if (("" + testOutput).indexOf(expected) != 0)
-    throw "Error: bad test output: expected leading digit to be " + expected + " but got " + testOutput;
+
+var expectedResults = [
+    { value: 0.018662099703860055, total: 0.018662099703860055 }, // 0
+    { value: 0, total: 0.018662099703860055 }, // 1
+    { value: -0.018662099703860055, total: 0 }, // 2
+    { value: -0.03650857609997156, total: -0.03650857609997156 }, // 3
+    { value: -0.05275945253292943, total: -0.08926802863290098 }, // 4
+    { value: -0.06670448772225647, total: -0.15597251635515746 }, // 5
+    { value: -0.07773421671447613, total: -0.23370673306963358 }, // 6
+    { value: -0.08536658742611654, total: -0.3190733204957501 }, // 7
+    { value: -0.08926802863290098, total: -0.40834134912865105 }, // 8
+    { value: -0.089268028632901, total: -0.49760937776155206 }, // 9
+    { value: -0.08536658742611655, total: -0.5829759651876686 }, // 10
+    { value: -0.07773421671447614, total: -0.6607101819021447 }, // 11
+    { value: -0.06670448772225651, total: -0.7274146696244013 }, // 12
+    { value: -0.052759452532929435, total: -0.7801741221573307 }, // 13
+    { value: -0.03650857609997158, total: -0.8166826982573023 }, // 14
+    { value: -0.018662099703860093, total: -0.8353447979611625 }, // 15
+    { value: -1.0992398059873222e-17, total: -0.8353447979611625 }, // 16
+    { value: 0.018662099703860034, total: -0.8166826982573024 }, // 17
+    { value: 0.036508576099971525, total: -0.780174122157331 }, // 18
+    { value: 0.052759452532929414, total: -0.7274146696244015 }, // 19
+    { value: 0.06670448772225647, total: -0.660710181902145 }, // 20
+    { value: 0.0777342167144761, total: -0.5829759651876689 }, // 21
+    { value: 0.08536658742611654, total: -0.4976093777615524 }, // 22
+    { value: 0.08926802863290098, total: -0.4083413491286514 }, // 23
+    { value: 0.089268028632901, total: -0.3190733204957504 }, // 24
+    { value: 0.08536658742611655, total: -0.23370673306963383 }, // 25
+    { value: 0.07773421671447615, total: -0.1559725163551577 }, // 26
+    { value: 0.06670448772225653, total: -0.08926802863290116 }, // 27
+    { value: 0.052759452532929435, total: -0.036508576099971726 }, // 28
+    { value: 0.03650857609997163, total: -9.71445146547012e-17 }, // 29
+    { value: 0.018662099703860107, total: 0.01866209970386001 }, // 30
+    { value: 2.1984796119746444e-17, total: 0.01866209970386003 }, // 31
+    { value: -0.018662099703859986, total: 4.5102810375396984e-17 }, // 32
+    { value: -0.03650857609997152, total: -0.036508576099971476 }, // 33
+    { value: -0.05275945253292941, total: -0.08926802863290088 }, // 34
+    { value: -0.06670448772225643, total: -0.1559725163551573 }, // 35
+    { value: -0.0777342167144761, total: -0.2337067330696334 }, // 36
+    { value: -0.08536658742611652, total: -0.31907332049574993 }, // 37
+    { value: -0.08926802863290098, total: -0.40834134912865094 }, // 38
+    { value: -0.089268028632901, total: -0.49760937776155195 }, // 39
+    { value: -0.08536658742611655, total: -0.5829759651876685 }, // 40
+    { value: -0.07773421671447617, total: -0.6607101819021446 }, // 41
+    { value: -0.06670448772225658, total: -0.7274146696244012 }, // 42
+    { value: -0.05275945253292945, total: -0.7801741221573306 }, // 43
+    { value: -0.03650857609997164, total: -0.8166826982573022 }, // 44
+    { value: -0.018662099703860194, total: -0.8353447979611625 }, // 45
+    { value: -3.2977194179619666e-17, total: -0.8353447979611625 }, // 46
+    { value: 0.018662099703859975, total: -0.8166826982573024 }, // 47
+    { value: 0.036508576099971435, total: -0.7801741221573311 }, // 48
+    { value: 0.0527594525329294, total: -0.7274146696244017 }, // 49
+    { value: 0.06670448772225643, total: -0.6607101819021453 }, // 50
+    { value: 0.07773421671447606, total: -0.5829759651876691 }, // 51
+    { value: 0.08536658742611652, total: -0.4976093777615526 }, // 52
+    { value: 0.08926802863290097, total: -0.40834134912865167 }, // 53
+    { value: 0.08926802863290101, total: -0.31907332049575066 }, // 54
+    { value: 0.08536658742611655, total: -0.2337067330696341 }, // 55
+    { value: 0.07773421671447617, total: -0.15597251635515794 }, // 56
+    { value: 0.06670448772225658, total: -0.08926802863290136 }, // 57
+    { value: 0.052759452532929456, total: -0.0365085760999719 }, // 58
+    { value: 0.03650857609997165, total: -2.498001805406602e-16 }, // 59
+    { value: 0.018662099703860208, total: 0.018662099703859958 }, // 60
+    { value: 4.396959223949289e-17, total: 0.018662099703860003 }, // 61
+    { value: -0.01866209970385996, total: 4.163336342344337e-17 }, // 62
+    { value: -0.03650857609997142, total: -0.03650857609997138 }, // 63
+    { value: -0.0527594525329294, total: -0.08926802863290079 }, // 64
+    { value: -0.06670448772225641, total: -0.1559725163551572 }, // 65
+    { value: -0.07773421671447604, total: -0.23370673306963324 }, // 66
+    { value: -0.08536658742611652, total: -0.31907332049574977 }, // 67
+    { value: -0.08926802863290097, total: -0.4083413491286507 }, // 68
+    { value: -0.08926802863290101, total: -0.49760937776155173 }, // 69
+    { value: -0.08536658742611655, total: -0.5829759651876683 }, // 70
+    { value: -0.07773421671447618, total: -0.6607101819021445 }, // 71
+    { value: -0.06670448772225658, total: -0.727414669624401 }, // 72
+    { value: -0.05275945253292948, total: -0.7801741221573305 }, // 73
+    { value: -0.036508576099971664, total: -0.8166826982573022 }, // 74
+    { value: -0.018662099703860215, total: -0.8353447979611625 }, // 75
+    { value: -5.496199029936611e-17, total: -0.8353447979611625 }, // 76
+    { value: 0.01866209970385995, total: -0.8166826982573026 }, // 77
+    { value: 0.036508576099971414, total: -0.7801741221573312 }, // 78
+    { value: 0.05275945253292938, total: -0.7274146696244018 }, // 79
+    { value: 0.0667044877222563, total: -0.6607101819021455 }, // 80
+    { value: 0.07773421671447604, total: -0.5829759651876695 }, // 81
+    { value: 0.08536658742611652, total: -0.49760937776155295 }, // 82
+    { value: 0.08926802863290097, total: -0.408341349128652 }, // 83
+    { value: 0.08926802863290101, total: -0.319073320495751 }, // 84
+    { value: 0.08536658742611655, total: -0.23370673306963444 }, // 85
+    { value: 0.07773421671447626, total: -0.1559725163551582 }, // 86
+    { value: 0.0667044877222566, total: -0.08926802863290159 }, // 87
+    { value: 0.05275945253292948, total: -0.036508576099972115 }, // 88
+    { value: 0.036508576099971816, total: -2.983724378680108e-16 }, // 89
+    { value: 0.018662099703860225, total: 0.018662099703859927 }, // 90
+    { value: 6.595438835923933e-17, total: 0.018662099703859993 }, // 91
+    { value: -0.018662099703859788, total: 2.0469737016526324e-16 }, // 92
+    { value: -0.0365085760999714, total: -0.0365085760999712 }, // 93
+    { value: -0.052759452532929366, total: -0.08926802863290056 }, // 94
+    { value: -0.06670448772225629, total: -0.15597251635515685 }, // 95
+    { value: -0.07773421671447604, total: -0.2337067330696329 }, // 96
+    { value: -0.08536658742611652, total: -0.31907332049574944 }, // 97
+    { value: -0.08926802863290095, total: -0.4083413491286504 }, // 98
+    { value: -0.08926802863290101, total: -0.4976093777615514 }, // 99
+    { value: -0.08536658742611657, total: -0.5829759651876679 }, // 100
+    { value: -0.07773421671447626, total: -0.6607101819021441 }, // 101
+    { value: -0.06670448772225661, total: -0.7274146696244007 }, // 102
+    { value: -0.052759452532929484, total: -0.7801741221573302 }, // 103
+    { value: -0.03650857609997182, total: -0.816682698257302 }, // 104
+    { value: -0.01866209970386024, total: -0.8353447979611622 }, // 105
+    { value: -7.694678641911255e-17, total: -0.8353447979611623 }, // 106
+    { value: 0.018662099703859774, total: -0.8166826982573026 }, // 107
+    { value: 0.0365085760999714, total: -0.7801741221573312 }, // 108
+    { value: 0.05275945253292936, total: -0.7274146696244018 }, // 109
+    { value: 0.06670448772225629, total: -0.6607101819021455 }, // 110
+    { value: 0.07773421671447603, total: -0.5829759651876695 }, // 111
+    { value: 0.08536658742611652, total: -0.49760937776155295 }, // 112
+    { value: 0.08926802863290095, total: -0.408341349128652 }, // 113
+    { value: 0.08926802863290101, total: -0.319073320495751 }, // 114
+    { value: 0.08536658742611657, total: -0.2337067330696344 }, // 115
+    { value: 0.07773421671447626, total: -0.15597251635515813 }, // 116
+    { value: 0.06670448772225661, total: -0.08926802863290152 }, // 117
+    { value: 0.0527594525329295, total: -0.036508576099972025 }, // 118
+    { value: 0.03650857609997184, total: -1.8735013540549517e-16 }, // 119
+];
+
+var valueError = 0.00000000000001;
+var totalError = 0.0000000000001;
+
+function expect(i, value, total) {
+    var data = expectedResults;
+    var valueDiff = Math.abs(value - data[i].value);
+    var totalDiff = Math.abs(total - data[i].total);
+
+    var err = null;
+    if (valueDiff > valueError && totalDiff > totalError)
+        err = "    [" + i + "] value a:" + value + " e:" + data[i].value + " | d:" + valueDiff + ", total a:" + total + " e:" + data[i].total + " | d: " + totalDiff;
+    else if (valueDiff > valueError)
+        err = "    [" + i + "] value a:" + value + " e:" + data[i].value + " | d:" + valueDiff;
+    else if (totalDiff > totalError)
+        err = "    [" + i + "] total a:" + total + " e:" + data[i].total + " | d: " + totalDiff;
+
+    if (err)
+        throw err;
+}
+
+testOutput = 0;
+for (var i = 0; i < nx; i++) {
+    var value = a[3*(i*nx+i)+1];
+    testOutput += value;
+    expect(i, value, testOutput);
+}
+a = null;