How can I plot data from a Swift sandbox? - swift

Question

I am practicing with Swift 3.x and I need to plot some data. The problem is that I only really have IBM's online Swift sandbox to work with. The purpose of the plotting is to understand how single-precision code is affected by summations:
I wrote some code to do this, but now I have no clue how to plot this. I doubt Swift can somehow bring up a window for plotting, let alone do so when run through the online sandbox.
Side note: I might be able to VNC into a Mac computer at my university to use Xcode. If I paste the same code into an Xcode project, could it make plots?
Here is the code in case you wanted to see it. I need to now run this code for N=1 to N=1,000,000.
import Foundation
func sum1(N: Int) -> Float {
var sum1_sum: Float = 0.0
var n_double: Double = 0.0
for n in 1...(2*N) {
n_double = Double(n)
sum1_sum += Float(pow(-1.0,n_double)*(n_double/(n_double+1.0)))
}
return sum1_sum
}
func sum2(N: Int) -> Float {
var sum2_sum: Float = 0.0
var n_double: Double = 0.0
var sum2_firstsum: Float = 0.0
var sum2_secondsum: Float = 0.0
for n in 1...N {
n_double = Double(n)
sum2_firstsum += Float((2.0*n_double - 1)/(2.0*n_double))
sum2_secondsum += Float((2.0*n_double)/(2.0*n_double + 1))
}
sum2_sum = sum2_secondsum - sum2_firstsum //This is where the subtractive cancellation occurs
return sum2_sum
}
func sum3(N: Int) -> Float {
var sum3_sum: Float = 0.0
var n_double: Double = 0.0
for n in 1...N {
n_double = Double(n)
sum3_sum += Float(1/(2.0*n_double*(2.0*n_double + 1)))
}
return sum3_sum
}
print("Sum 1:", sum1(N: 1000000))
print("Sum 2:", sum2(N: 1000000))
print("Sum 3:", sum3(N: 1000000))

Answer 1

Yes, #TheSoundDefense is right. There is no plotting output from the Swift Sandbox directly. However, I recommend that you still use the Swift Sandbox. Just run the code, and copy and paste the output in comma-delimited format to Excel or MATLAB to plot it. I did some tweaking to your sum2 as an example, while also making it a bit more functional in the process:
func sum2(N: Int) -> Float {
let a: Float = (1...N).reduce(0) {
let nDouble = Double($1)
return Float((2.0 * nDouble - 1) / (2.0 * nDouble)) + $0
}
let b: Float = (1...N).reduce(0) {
let nDouble = Double($1)
return Float((2.0 * nDouble) / (2.0 * nDouble + 1)) + $0
}
return b - a
}
let N = 10
let out = (1...N).map(){ sum2(N: $0)}
let output = out.reduce(""){$0 + "\($1), "}
print(output)
0.166667, 0.216667, 0.240476, 0.254365, 0.263456, 0.269867, 0.274629, 0.278306, 0.28123, 0.283611,