R中的h2o.predict错误 [英] Error with h2o.predict in R

问题描述

尝试在R中使用h2o创建深度学习预测时遇到错误。使用命令h2o.predict约有三分之一的预测发生错误。这是模型设置：

I am getting an error when trying to create deep learning predictions with h2o in R. The error occurs for about one third of predictions with the command h2o.predict. Here is the model setup:

localH2O = h2o.init(ip = "localhost", port = 54321, startH2O = TRUE,max_mem_size='20g',nthreads=6)
model <- h2o.deeplearning(x = 2:100, y = 1, training_frame = x, l1 = 1e-5, l2 = 1e-5, epochs=500, hidden = c(800,800,100))
prediction <- h2o.predict(model, x[,2:100])

以下是打开和关闭时发生的错误：

Here is the error that occurs on and off:

ERROR: Unexpected HTTP Status code: 500 Server Error (url = http://localhost:54321/99/Rapids)

java.lang.RuntimeException
[1] "water.MRTask.getResult(MRTask.java:505)"                                              
[2] "water.MRTask.doAll(MRTask.java:379)"                                                  
[3] "water.MRTask.doAll(MRTask.java:375)"                                                  
[4] "water.rapids.ASTRowSlice.apply(ASTColSlice.java:123)"                                 
[5] "water.rapids.ASTExec.exec(ASTExec.java:46)"                                           
[6] "water.rapids.ASTTmpAssign.apply(ASTAssign.java:255)"                                  
[7] "water.rapids.ASTTmpAssign.apply(ASTAssign.java:248)"                                  
[8] "water.rapids.ASTExec.exec(ASTExec.java:46)"                                           
[9] "water.rapids.Session.exec(Session.java:56)"                                           
[10] "water.rapids.Exec.exec(Exec.java:63)"                                                 
[11] "water.api.RapidsHandler.exec(RapidsHandler.java:23)"                                  
[12] "sun.reflect.GeneratedMethodAccessor8.invoke(Unknown Source)"                          
[13] "sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)"
[14] "java.lang.reflect.Method.invoke(Method.java:497)"                                     
[15] "water.api.Handler.handle(Handler.java:64)"                                            
[16] "water.api.RequestServer.handle(RequestServer.java:644)"                               
[17] "water.api.RequestServer.serve(RequestServer.java:585)"                                
[18] "water.JettyHTTPD$H2oDefaultServlet.doGeneric(JettyHTTPD.java:617)"                    
[19] "water.JettyHTTPD$H2oDefaultServlet.doPost(JettyHTTPD.java:565)"                       
[20] "javax.servlet.http.HttpServlet.service(HttpServlet.java:755)"                         
[21] "javax.servlet.http.HttpServlet.service(HttpServlet.java:848)"                         
[22] "org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:684)"               

Show Traceback

Rerun with Debug
Error in .h2o.doSafeREST(h2oRestApiVersion = h2oRestApiVersion, urlSuffix = page,  : 
water.DException$DistributedException: from /127.0.0.1:54321; by class water.rapids.ASTRowSlice$1; class java.lang.NegativeArraySizeException: null Error in class(obj) <- "rs.scalar" : attempt to set an attribute on NULL

以下是我的系统架构。正在运行的系统（ java -version）给出：

Here is something about my system architecture. Running system("java -version") gives:

java version "1.8.0_65"
Java(TM) SE Runtime Environment (build 1.8.0_65-b17)
Java HotSpot(TM) 64-Bit Server VM (build 25.65-b01, mixed mode)

这是sessionInfo（）的输出：

Here is the output of sessionInfo():

R version 3.2.2 (2015-08-14)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows Server 2008 R2 x64 (build 7601) Service Pack 1

locale:
[1] LC_COLLATE=Danish_Denmark.1252  LC_CTYPE=Danish_Denmark.1252    LC_MONETARY=Danish_Denmark.1252
[4] LC_NUMERIC=C                    LC_TIME=Danish_Denmark.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] h2o_3.6.0.8              statmod_1.4.22           TTR_0.23-0               selectiveInference_1.1.1
[5] intervals_0.15.1         lars_1.2                 glmnet_2.0-2             foreach_1.4.3           
[9] Matrix_1.2-2             wq_0.4.4                 zoo_1.7-12               skm_1.0.2               
[13] stringi_1.0-1            devtools_1.9.1          

loaded via a namespace (and not attached):
[1] Rcpp_0.12.2      magrittr_1.5     MASS_7.3-43      munsell_0.4.2    colorspace_1.2-6
[6] lattice_0.20-33  stringr_1.0.0    plyr_1.8.3       xts_0.9-7        tools_3.2.2     
[11] grid_3.2.2       gtable_0.1.2     iterators_1.0.8  digest_0.6.8     reshape2_1.4.1  
[16] ggplot2_1.0.1    bitops_1.0-6     codetools_0.2-14 RCurl_1.95-4.7   memoise_0.2.1   
[21] scales_0.3.0     jsonlite_0.9.19  proto_0.3-10    

非常感谢任何帮助。

推荐答案

您遇到的错误是由内部错误引起的H2O语言处理框架（称为Rapids）。

The error you've hit upon is originating from the internal H2O language processing framework (called Rapids).

可能的罪魁祸首不是预测，而是代码片段

The likely culprit is not predict, but rather the snippet

   x[,2:100]

其中 >应该正在执行列切片（ASTColSlice）。但是看起来它正在ASTRowSlice中执行代码...如果您能够提供任何日志，则可以更好地处理正在发生的事情（此处的stdout / err帮助，您可以使用方法获取它们

which should be doing a column slice (ASTColSlice). But it looks like it's executing code in ASTRowSlice... Could get a better handle on what's going on if you're able to provide any logs (the stdout/err help here, you can get them with the method

        h2o.downloadAllLogs

一件突出的事情是：

  Error in class(obj) <- "rs.scalar" : attempt to set an attribute on NULL

rs.scalar的属性在我们的R代码中没有任何意义，是无论如何，日志应该更清楚地说明NegativeArraySizeException的发生方式。

"rs.scalar" doesn't have any significance in our R code, is it something that you recognize? At any rate, the logs should shed more light on how the NegativeArraySizeException is occurring.

谢谢！

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