---
title: ignoreRowsAndColumns
framework: accelerate
role: symbol
role_heading: Instance Property
path: accelerate/sparsesymbolicfactoroptions/ignorerowsandcolumns
---

# ignoreRowsAndColumns

An array that contains row and column indices to ignore.

## Declaration

```swift
var ignoreRowsAndColumns: UnsafeMutablePointer<Int32>?
```

## Discussion

Discussion If this array isn’t nil, ignoreRowsAndColumns provides a list of rows and columns to ignore. Terminate ignoreRowsAndColumns with a negative index. The row and column indices are for the actual matrix, not its block structure, so 0 indicates the first row, not the first blockSize rows. In the symmetric case (Cholesky, LDLᵀ), each entry indicates that the system needs to ignore the matching row and column. In the unsymmetric case (QR, Cholesky AᵀA), consider the matrix, A, given the value m, with one of the following definitions: m = A.structure.rowCount * A.blockSize if A isn’t a transposed matrix m = A.structure.columnCount * A.blockSize if A is a transposed matrix In this case, an index less than m indicates that the system needs to ignore row m. An index i, greater than m, indicates that the system needs to ignore columns i - m.

## See Also

### Inspecting Symbolic Factor Options

- [control](accelerate/sparsesymbolicfactoroptions/control.md)
- [SparseControl_t](accelerate/sparsecontrol_t.md)
- [orderMethod](accelerate/sparsesymbolicfactoroptions/ordermethod.md)
- [order](accelerate/sparsesymbolicfactoroptions/order.md)
- [SparseOrder_t](accelerate/sparseorder_t.md)
- [malloc](accelerate/sparsesymbolicfactoroptions/malloc.md)
- [free](accelerate/sparsesymbolicfactoroptions/free.md)
- [reportError](accelerate/sparsesymbolicfactoroptions/reporterror.md)