# NAG CPP Interfaceopt::CommE04WB::setter_linesearchtolerance

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## 1Description

The value $r$ ($0\le r<1$) controls the accuracy with which the step $\alpha$ taken during each iteration approximates a minimum of the merit function along the search direction (the smaller the value of $r$, the more accurate the linesearch)
Used by: linesearchtolerance in e04ucf and e04uff (no CPP interface).
CommE04WB::setter_linesearchtolerance returns a reference to the communication class itself.

## 2Specification

 CommE04WB& LineSearchTolerance(double value = Default =0.9 )
 CommE04WB& LineSearchTolerance(double value = Default =0.9 , OptionalE04UE opt)

## 3Arguments

1: $\mathbf{value}$ double Scalar
On entry: the required value of the argument.
Default:
Default $\text{}=0.9$
2: $\mathbf{opt}$ OptionalE04UE Scalar
Optional argument container, derived from Optional.