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# vDSP_vthrsc

Calculates single-precision vector threshold with signed constant to the specified range.

```
extern void vDSP_vthrsc(const float *__A, vDSP_Stride __IA, const float *__B, const float *__C, float *__D, vDSP_Stride __ID, vDSP_Length __N);
```

## Parameters

`__A`

Single-precision real input vector

`__IA`

Stride for `A`

`__B`

Pointer to single-precision real input scalar: lower threshold

`__C`

Pointer to single-precision real input scalar: output constant

`__D`

Single-precision real output vector

`__ID`

Stride for `D`

`__N`

The number of elements to process

## Discussion

Performs the following operation:

```objc
for (n = 0; n < N; ++n){
    if (A[n*IA] >= *B)
        D[n*Id] = *C;
    else
        D[n*Id] = -*C;
}
```

Creates vector `D` using the plus or minus value of scalar `*C`. The sign of  the output element is determined by comparing input from vector `A` with  threshold scalar `*B`. For input values less than `*B`, the negated value of `*C` is written to vector `D`.  For input values greater than or equal to `*B`, `*C` is copied to vector `D`.

---

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