# KSPFCDTruncationType
Define how stored directions are used to orthogonalize in flexible conjugate directions (FCD) methods 
## Synopsis
```
typedef enum {
  KSP_FCD_TRUNC_TYPE_STANDARD,
  KSP_FCD_TRUNC_TYPE_NOTAY
} KSPFCDTruncationType;
```

## Values

- ***`KSP_FCD_TRUNC_TYPE_STANDARD` -*** uses all (up to mmax) stored directions
- ***`KSP_FCD_TRUNC_TYPE_NOTAY` -*** uses the last max(1,mod(i,mmax)) stored directions at iteration i=0,1..





## See Also
 `KSP`, `KSPFCG`, `KSPPIPEFCG`, `KSPPIPEGCR`, `KSPFCGSetTruncationType()`, `KSPFCGGetTruncationType()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/include/petscksp.h.html#KSPFCDTruncationType">include/petscksp.h</A>


---
[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/include/petscksp.h)


[Index of all KSP routines](index.md)  
[Table of Contents for all manual pages](/docs/manualpages/index.md)  
[Index of all manual pages](/docs/manualpages/singleindex.md)  
