---
title: vDSP_svsD
framework: accelerate
role: symbol
role_heading: Function
path: accelerate/vdsp_svsd
---

# vDSP_svsD

Calculates the sum of signed squares in a double-precision vector.

## Declaration

```occ
extern void vDSP_svsD(const double *__A, vDSP_Stride __IA, double *__C, vDSP_Length __N);
```

## Parameters

- `__A`: Double-precision real input vector.
- `__IA`: Stride for A
- `__C`: Double-precision real output scalar
- `__N`: The number of elements to process

## Discussion

Discussion This function calculates the sum of the signed squares of the first N elements of A and writes the result to C:

The operation is: C[0] = sum(A[n] * |A[n]|, 0 <= n < N);

## See Also

### Vector Summation

- [vDSP_sve](accelerate/vdsp_sve.md)
- [vDSP_sveD](accelerate/vdsp_sved.md)
- [vDSP_svemg](accelerate/vdsp_svemg.md)
- [vDSP_svemgD](accelerate/vdsp_svemgd.md)
- [vDSP_svesq](accelerate/vdsp_svesq.md)
- [vDSP_svesqD](accelerate/vdsp_svesqd.md)
- [vDSP_sve_svesq](accelerate/vdsp_sve_svesq.md)
- [vDSP_sve_svesqD](accelerate/vdsp_sve_svesqd.md)
- [vDSP_svs](accelerate/vdsp_svs.md)