0000902: bad derivative

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Date Submitted

Last Update

0000902

Community

[OCCT] OCCT:Foundation Classes

public

2002-10-25 11:24

2011-12-15 17:54

Reporter

emo

Assigned To

vtn

Priority

normal

Severity

trivial

Status

closed

Resolution

fixed

Platform

All

OS Version

Product Version

Target Version

Fixed in Version

[OCCT] 5.1.0

Summary

0000902: bad derivative

Description

This bug has been added by Jacques Leroy at
http://www.opencascade.org/forumorg/bug.php?bug_id=88&f=8 [^] .

in ~/src/Expr/Expr_Exponential.cxx

the Derivative() method:

Handle(Expr_GeneralExpression) Expr_Exponential::Derivative (const Handle
(Expr_NamedUnknown)& X) const
{
  if (!Contains(X)) {
    return new Expr_NumericValue(0.0);
  }
  Handle(Expr_GeneralExpression) myexp = Operand();
  Handle(Expr_GeneralExpression) myder = myexp->Derivative(X);
  Handle(Expr_Product) resu = Expr::CopyShare(myexp) * myder;
  return resu->ShallowSimplified();
}

is wrong. (Indeed Exponential(X).Derivative(X) gives X !!)

It should be: (see BUG FIX)

Handle(Expr_GeneralExpression) Expr_Exponential::Derivative (const Handle
(Expr_NamedUnknown)& X) const
{
  if (!Contains(X)) {
    return new Expr_NumericValue(0.0);
  }
  Handle(Expr_GeneralExpression) myexp = Operand();
  Handle(Expr_GeneralExpression) myder = myexp->Derivative(X);
  Handle(Expr_Product) resu = Expr::CopyShare(this) * myder; // BUG FIX !!
  return resu->ShallowSimplified();
}

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Attached Files

Expr.zip (1,011 bytes) 2003-04-29 13:11

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Issue History
Date Modified	Username	Field	Change
2002-10-25 11:26	bugmaster	Assigned To	bugmaster => vtn
2002-10-25 11:26	bugmaster	Status	new => assigned
2003-04-29 17:11	vtn	Status	assigned => resolved
2003-04-30 11:40	apv	CC	=> apv
2003-04-30 12:03	apv	CC	=> aki
2003-06-02 12:46	bugmaster	Status	resolved => closed
2003-06-02 12:46	bugmaster	Resolution	@0@ => fixed
2011-08-02 11:23	bugmaster	Category	OCCT:FDC => OCCT:Foundation Classes
2011-12-15 17:54	bugmaster	Project	Open CASCADE => Community