# SparseGetInertia(_:_:_:_:) Returns the inertia of a double-precision *LDLᵀ* factorization. ``` func SparseGetInertia(_ Factored: SparseOpaqueFactorization_Double, _ num_positive: UnsafeMutablePointer, _ num_zero: UnsafeMutablePointer, _ num_negative: UnsafeMutablePointer) -> Int32 ``` ## Parameters `Factored` The [`SparseFactorizationLDLTTPP`](/documentation/Accelerate/SparseFactorizationLDLTTPP) factorization. `num_positive` On return, the number of positive pivots the sparse factorization functions take during the factorization of `Factored`. `num_zero` On return, the number of zero pivots the sparse factorization functions take during the factorization of `Factored`. `num_negative` On return, the number of negative pivots the sparse factorization functions take during the factorization of `Factored`. ## Return Value `0` on success; otherwise, a nonzero value on error. ## Discussion This function returns the number of negative, zero, and positive pivots that the sparse factorization functions, [`SparseFactor(_:_:)`](/documentation/Accelerate/SparseFactor(_:_:)-8gl6j) and [`SparseFactor(_:_:_:_:)`](/documentation/Accelerate/SparseFactor(_:_:_:_:)-88xmk), take during an *LDLᵀ* factorization. In some cases — for example, when the original matrix’s eigenvalues are close to zero — the computed numerical inertia may not be an accurate reflection of the true inertia. In such cases, the computed numerical inertia is dependent on the [`zeroTolerance`](/documentation/Accelerate/SparseNumericFactorOptions/zeroTolerance) and [`pivotTolerance`](/documentation/Accelerate/SparseNumericFactorOptions/pivotTolerance) values of the [`SparseNumericFactorOptions`](/documentation/Accelerate/SparseNumericFactorOptions) structure. > Important: > This function supports only ``doc://com.apple.accelerate/documentation/Accelerate/SparseFactorizationLDLTTPP`` factorizations. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)