[ https://issues.apache.org/jira/browse/PIG-4265?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
liyunzhang_intel updated PIG-4265: ---------------------------------- Attachment: PIG-4265.patch The modification of this patch is: Use BigDecimal to solve the problem {code} AlgebraicDoubleMathBase.java private static Double doWork(Double arg1, Double arg2, KNOWN_OP op) { if (arg1 == null) { return arg2; } else if (arg2 == null) { return arg1; } else { switch (op) { case MAX: return Math.max(arg1, arg2); case MIN: return Math.min(arg1, arg2); case SUM: return BigDecimal.valueOf(arg1).add(BigDecimal.valueOf(arg2)).doubleValue(); default: return null; } } } {code} > AlgebraicDoubleMathBase has "Java double precision problems" > ------------------------------------------------------------ > > Key: PIG-4265 > URL: https://issues.apache.org/jira/browse/PIG-4265 > Project: Pig > Issue Type: Bug > Reporter: liyunzhang_intel > Attachments: PIG-4265.patch > > > $PIG_HOME/bin/pig -x local RubyUDFs_10.pig > #RubyUDFs_10.pig > register '/home/zly/prj/oss/pig/bin/libexec/ruby/scriptingudfs.rb' using > jruby as myfuncs; > a = load 'studenttab10k' using PigStorage() as (name, age:int, gpa:double); > b = group a by name; > c = foreach b generate group, myfuncs.Sum(a.age), myfuncs.Sum(a.gpa); > d = foreach c generate $0, $1, (double)((int)$2*100)/100; > store d into 'RubyUDFs_10.out'; > the result in RubyUDFs_10.out/part > #grep "david s" RubyUDFs_10.out/part-r-00000 > david steinbeck 266 15.0 > #grep "david s" studenttab10k > david steinbeck 21 2.44 > david steinbeck 33 1.17 > david steinbeck 42 1.94 > david steinbeck 42 1.35 > david steinbeck 31 2.77 > david steinbeck 40 2.42 > david steinbeck 57 3.91 > when you sum all the gpa of "david steinbeck" in the file "studenttab10k", > the result is "16" while the result in RubyUDFs_10.out/part-r-00000 is "15". > The reason is because double precision problem in > AlgebraicDoubleMathBase.java. > It sums all the gpa numbers to 15.999999-(double)((int)15.999999*100)/100 = > 15.0. > {code} > AlgebraicDoubleMathBase.java > private static Double doWork(Double arg1, Double arg2, KNOWN_OP op) { > if (arg1 == null) { > return arg2; > } else if (arg2 == null) { > return arg1; > } else { > switch (op) { > case MAX: return Math.max(arg1, arg2); > case MIN: return Math.min(arg1, arg2); > case SUM: return arg1+arg2; //this line has "Java BigDecimal > precision problem" > default: return null; > } > } > } > {code} > The detail Java double precision problem you can refer > "https://community.oracle.com/thread/2448849?tstart=0" -- This message was sent by Atlassian JIRA (v6.3.4#6332)