Contents

linearInterpolate(lookupTable:withOffsets:scale:baseOffset:result:)

Computes the single-precision linearly interpolated values of a lookup table from the specified offsets.

Declaration

static func linearInterpolate<T, U, V>(lookupTable: T, withOffsets offsets: U, scale: Float = 1, baseOffset: Float = 0, result: inout V) where T : AccelerateBuffer, U : AccelerateBuffer, V : AccelerateMutableBuffer, T.Element == Float, U.Element == Float, V.Element == Float

Parameters

  • lookupTable:

    The lookup table.

  • offsets:

    The offsets into the lookup table.

  • scale:

    The scale factor for the offsets.

  • baseOffset:

    The base offset for the offsets.

  • result:

    The destination vector that receives the result.

Discussion

The following code shows the result of linearly interpolating a lookup table that contains the values [-10, 0, 100] using the offsets [0, 0.5, 1, 1.5, 2]. The integer offsets, 0, 1, and 2, return the corresponding values in the lookup table, -10, 0, and 2. The noninteger offsets, 0.5 and 1.5, return the linearly interpolated values between the lookup table values, -5 and 50.

let lookupTable: [Float] = [-10, 0, 100]
let offsets: [Float] = [0, 0.5, 1, 1.5, 2]

let count = offsets.count

let result = [Float](unsafeUninitializedCapacity: count) {
    buffer, initializedCount in
    
    vDSP.linearInterpolate(lookupTable: lookupTable,
                                        withOffsets: offsets,
                                        result: &buffer)
    
    initializedCount = count
}

// Prints "[-10.0, -5.0, 0.0, 50.0, 100.0]".
print(result)

See Also

Type Methods