---
title: vDSP_vgenD
framework: accelerate
role: symbol
role_heading: Function
path: accelerate/vdsp_vgend
---

# vDSP_vgenD

Generates a double-precision vector that contains monotonically incrementing or decrementing values within a range.

## Declaration

```occ
extern void vDSP_vgenD(const double *__A, const double *__B, double *__C, vDSP_Stride __IC, vDSP_Length __N);
```

## Parameters

- `__A`: The start value of the ramp.
- `__B`: The end value of the ramp.
- `__C`: The output vector.
- `__IC`: The distance between the elements in the output vector.
- `__N`: The number of elements that the function processes.

## Discussion

Discussion Use this function to generate and return a vector populated with ramped values. The following code generates a ramped vector with values in the range 0 ... 7:     let n = 8     let stride = 1          var start: Double = 0     var end: Double = 7          let ramp = [Double](unsafeUninitializedCapacity: n) {         buffer, initializedCount in                  vDSP_vgenD(&start,                    &end,                    buffer.baseAddress!,                    stride,                    vDSP_Length(n))                  initializedCount = n     }          // Prints "[0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0]".     print(ramp)

## See Also

### Vector generation with ramps using a range

- [vDSP_vgen](accelerate/vdsp_vgen.md)