---
title: btol
framework: accelerate
role: symbol
role_heading: Instance Property
path: accelerate/sparselsmroptions/btol
---

# btol

The B tolerance (Fong-Saunders test only).

## Declaration

```swift
var btol: Double
```

## Discussion

Discussion This value holds an estimate of the relative error in the data defining the right-hand-side, b. For example, if b is accurate to about six digits, set btol = 1.0e-6.

## See Also

### Inspecting LSMR Options

- [atol](accelerate/sparselsmroptions/atol.md)
- [conditionLimit](accelerate/sparselsmroptions/conditionlimit.md)
- [convergenceTest](accelerate/sparselsmroptions/convergencetest.md)
- [SparseLSMRConvergenceTest_t](accelerate/sparselsmrconvergencetest_t.md)
- [lambda](accelerate/sparselsmroptions/lambda.md)
- [maxIterations](accelerate/sparselsmroptions/maxiterations.md)
- [nvec](accelerate/sparselsmroptions/nvec.md)
- [reportError](accelerate/sparselsmroptions/reporterror.md)
- [reportStatus](accelerate/sparselsmroptions/reportstatus.md)
- [rtol](accelerate/sparselsmroptions/rtol.md)