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0006666

ParaView

(No Category)

public

2008-03-27 10:55

2009-05-13 13:47

Reporter

Takuya OSHIMA

Assigned To

Zhanping Liu

Priority

normal

Severity

minor

Reproducibility

always

Status

closed

Resolution

fixed

Platform

OS Version

Product Version

Target Version

3.6

Fixed in Version

Summary

0006666: vtkFunctionParser::OperatorWithinVariable() should search variable name until the location of idx

Description

I have a dataset which contains an array with the name say "A/B," which in turn contains a character that may be interpreted as a mathematical operator '/'. If I try to run Filter->Calculator and to evaluate an expression "A/B + A/B" over the dataset, I can't get the expected result (an array with all components doubled). The actual result depends on the expression (a parser error, an incorrect result array, etc.).

Additional Information

I think finding only the first occurrence of the array name within the given expression is not enough in vtkFunctionParser::OperatorWithinVariable(). At least the array name should be searched until the location of idx even if there was an occurrence prior to the location.

The attached is a patch that worked for me. I know this is far from perfect as a fix (there are still many possible cases that can't be covered with this patch). Please take it just as a clarification of the solution that worked for me.

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Attached Files

patch1 [^] (1,927 bytes) 2008-03-27 10:55 [Show Content] [Hide Content]

--- vtkFunctionParser.cxx.orig	2007-12-22 03:55:56.000000000 +0900
+++ vtkFunctionParser.cxx	2008-03-22 12:26:51.320000000 +0900
@@ -1342,14 +1342,21 @@
     {
     if (strchr(this->ScalarVariableNames[i], this->Function[idx]) != 0)
       {
-      tmpString = strstr(this->Function, this->ScalarVariableNames[i]);
-      if (tmpString)
+      for(end = 0; end <= idx;)
         {
-        start = static_cast<int>(tmpString - this->Function);
-        end = start + strlen(this->ScalarVariableNames[i]);
-        if (start <= idx && end >= idx)
+        tmpString = strstr(this->Function + end, this->ScalarVariableNames[i]);
+        if (tmpString)
           {
-          return 1;
+          start = static_cast<int>(tmpString - this->Function);
+          end = start + strlen(this->ScalarVariableNames[i]);
+          if (start <= idx && end > idx)
+            {
+            return 1;
+            }
+          }
+        else
+          {
+          break;
           }
         }
       }
@@ -1358,14 +1365,21 @@
     {
     if (strchr(this->VectorVariableNames[i], this->Function[idx]) != 0)
       {
-      tmpString = strstr(this->Function, this->VectorVariableNames[i]);
-      if (tmpString)
+      for(end = 0; end <= idx;)
         {
-        start = static_cast<int>(tmpString - this->Function);
-        end = start + strlen(this->VectorVariableNames[i]);
-        if (start <= idx && end >= idx)
+        tmpString = strstr(this->Function + end, this->VectorVariableNames[i]);
+        if (tmpString)
+          {
+          start = static_cast<int>(tmpString - this->Function);
+          end = start + strlen(this->VectorVariableNames[i]);
+          if (start <= idx && end > idx)
+            {
+            return 1;
+            }
+          }
+        else
           {
-          return 1;
+          break;
           }
         }
       }

Relationships

Notes
(0013780) Zhanping Liu (developer) 2008-10-09 09:47	BUG: 0006666 has been fixed. The problem was due to the insufficient search, in this->Function, for a variable name containing a dumb operator. This incompleteness fails to capture such a variable name at index "idx" if there happens to be one or more occurrences (of the same variable name) preceding idx. As a consequence, vtkFunctionParser:: OperatorWithinVariable() --- (line1335 ~ line 1403) --- mistakenly reports 0. As suggested by 7islands, a greedy search scheme is now adopted to check through idx before reporting the result. The updated code allows for multiple occurrences of a varialbe name (containing a dumb operator) in this->Function and therefore leads to a more flexible function parser. Thanks, 7islands, for reporting the bug and the suggestions. new revision: 1.41; previous revision: 1.40

(0013929) Alan Scott (manager) 2008-10-24 20:04	No clue how to check this, assuming correct. Untested.

Issue History
Date Modified	Username	Field	Change
2008-03-27 10:55	Takuya OSHIMA	New Issue
2008-03-27 10:55	Takuya OSHIMA	File Added: patch1
2008-04-10 17:44	Ken Moreland	Category	3.4 => 3.6
2008-09-23 11:21	Berk Geveci	Status	backlog => tabled
2008-09-23 11:21	Berk Geveci	Assigned To	=> Zhanping Liu
2008-10-09 09:47	Zhanping Liu	Note Added: 0013780
2008-10-09 09:48	Zhanping Liu	Status	tabled => @80@
2008-10-24 20:04	Alan Scott	Note Added: 0013929
2008-10-24 20:04	Alan Scott	Status	@80@ => closed
2008-10-24 20:04	Alan Scott	Resolution	open => fixed
2009-05-13 13:47	Utkarsh Ayachit	Target Version	=> 3.6
2011-06-16 13:10	Zack Galbreath	Category	=> (No Category)