ios - 初始输入后计算器卡住

Question

我编写这段代码是为了计算一种叫做 B 因子的东西。最初一切都很好。输入压力和温度，B 因子就会出来。但是，当我输入新的压力和温度值时，应用程序似乎卡住了。

我的代码如下:

import Foundation
class bFactorFormula {
    var NK_VALUES:[Double] = [0.924803575275, -0.492448489428, 0.661883336938, -1.92902649201, -0.0622469309629, 0.349943957581, 0.564857472498, -1.61720005987, -0.481395031883, 0.421150636384, -0.0161962230825, 0.172100994165, 0.00735448924933, 0.0168077305479, -0.00107626664179, -0.0137318088513, 0.000635466899859, 0.00304432279419, -0.0435762336045, -0.0723174889316, 0.0389644315272, -0.021220136391, 0.00408822981509, -0.0000551990017984, -0.0462016716479, -0.00300311716011, 0.0368825891208, -0.0025585684622, 0.00896915264558, -0.0044151337035, 0.00133722924858, 0.000264832491957, 19.6688194015, -20.915560073, 0.0167788306989, 2627.67566274]
    var IK_VALUES:[Double] = [1, 1, 2, 2, 3, 3, 1, 1, 1, 3, 3, 4, 6, 6, 7, 7, 8, 8, 1, 2, 3, 4, 5, 8, 4, 5, 5, 8, 3, 5, 6, 9, 1, 1, 3, 2]
    var JK_VALUES:[Double] = [0.25, 0.875, 0.5, 0.875, 0.375, 0.75, 0.5, 0.75, 2, 1.25, 3.5, 1, 0.5, 3, 0, 2.75, 0.75, 2.5, 4, 6, 6, 3, 3, 6, 16, 11, 15, 12, 12, 7, 4, 16, 0, 1, 2, 3]
    var LK_VALUES:[Double] = [0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 0, 0, 0, 0]
    var PK_VALUES:[Double] = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 20, 20, 15, 25]
    var BK_VALUES:[Double] = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0325, 325, 300, 275]
    var UK_VALUES:[Double] = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1.16, 1.16, 1.13, 1.25]
    var R_CONST = 8.31451
    var T_C:Double = 126.192
    var P_C:Double = 3.3958
    var MOLECULAR_WEIGHT:Double = 28.01348
    var DENSITY_STP:Double = 1.1851
    var RHO_C:Double = 11.1839

    // DECLARE INPUT VARIABLES
    var n2TemperatureInput:Double
    var n2PressureInput: Double
    var tempK:Double {
        get {
            return n2TemperatureInput + 273.15
        }
    }
    var tempR:Double {
        get {
            return T_C / tempK
        }
    }
    var pTarget:Double {
        get {
            return (n2PressureInput * 1000000) + 101325
        }
    }

    init (setBFactorTemperature:Double, setBFactorPressure:Double) {
        self.n2TemperatureInput = setBFactorTemperature
        self.n2PressureInput = setBFactorPressure
    }

    var rhoCurrent:Double = 0
    var rhoHigh:Double = 0
    var rhoLow:Double = 0
    var diffAggregate:Double = 0
    var diffSegment:Double = 0
    var iFactor:Double = 0
    var bFactor:Double = 0
    //
    // kIndex defined in the while-loop
    // var kIndex:Double = 0
    //
    var pCalc:Double = 0
    var zDiff:Double = 0
    var rhoR:Double = 0

    func retRhoCurrent() -> Double {

        while abs(pTarget - pCalc) > 1 {

            //
            // SET rhoCurrent
            //

            if (pTarget > pCalc) {
                rhoLow = rhoCurrent
                if(rhoCurrent >= rhoHigh) {
                    rhoCurrent += RHO_C
                    rhoHigh = rhoCurrent
                } else {
                    rhoCurrent += ((rhoHigh - rhoCurrent)/2)
                }
            } else {
                rhoHigh = rhoCurrent
                rhoCurrent += ((rhoLow - rhoCurrent)/2)
            }

            //
            // SET rhoR
            //

            rhoR = rhoCurrent / RHO_C

            //
            // SET DIFFERENTIAL
            //
            diffAggregate = 0
            for var kIndex = 0; kIndex < NK_VALUES.count; ++kIndex {
                diffSegment = NK_VALUES[kIndex]
                diffSegment *= pow(rhoR, IK_VALUES[kIndex])
                diffSegment *= pow(tempR, JK_VALUES[kIndex])
                iFactor = 0
                if LK_VALUES[kIndex] > 0 {
                    diffSegment *= exp(-1 * pow(rhoR, LK_VALUES[kIndex]))
                    iFactor = LK_VALUES[kIndex] * pow(rhoR, LK_VALUES[kIndex])
                }
                if PK_VALUES[kIndex] > 0 {
                    diffSegment *= exp(-1 * PK_VALUES[kIndex] * pow(rhoR, 2) - BK_VALUES[kIndex] * pow(tempR - UK_VALUES[kIndex], 2))
                    iFactor = 2 * rhoR * PK_VALUES[kIndex] * (rhoR - 1)
                }
                diffAggregate += (diffSegment * (IK_VALUES[kIndex] - iFactor))
            }

            //
            // SET pCalc
            //
            zDiff = 1 + diffAggregate
            pCalc = zDiff * R_CONST * 1000 * tempK * rhoCurrent
        }
        return rhoCurrent
    }
}

我在想我可能需要某种“刷新”命令，但我不确定该怎么做才正确。

此外 - 我想向大家展示我的 ViewController，看看我是如何执行此操作的。

import UIKit

extension Double {
func format(f: String) -> String {
    return NSString(format: "%\(f)f", self) as String
}
}

class NitrogenViewController: UIViewController {

@IBOutlet weak var bFactorPressureInput: UITextField!
@IBOutlet weak var bFactorTemperatureInput: UITextField!
@IBOutlet weak var bFactorResults: UILabel!

var calcBFactor = bFactorFormula(setBFactorTemperature: 10, setBFactorPressure: 10)

override func viewDidLoad() {
    super.viewDidLoad()

    // Do any additional setup after loading the view.
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

@IBAction func bFactorButton(sender: AnyObject) {

    calcBFactor.n2PressureInput = Double((bFactorPressureInput.text as NSString).doubleValue)
    calcBFactor.n2TemperatureInput = Double((bFactorTemperatureInput.text as NSString).doubleValue)
    var rhoCurrentReturned = calcBFactor.retRhoCurrent()
    var bFactorResult = rhoCurrentReturned * (28.01348/1.1851)
    var bFactorResultFormat = "0.2"
    bFactorResults.text = "The B-Factor is \(bFactorResult.format(bFactorResultFormat)) scm/m3"
}

我认为这与我的 View Controller 代码有关。有什么想法吗？

Answer 1

当 bFactorFormula 类被初始化时，看起来您正在将 pCalc 初始化为 0。没关系。但是在第一次运行 pCalc 之后是 10101321.0261427 并且当你再次运行计算时，你永远不会脱离你的 while 循环。

因此您可以在 IBAction 代码中为每次运行创建一个新的 bFactorForumula 对象，或者您可以在 retRhoCurrent 的顶部设置 pCalc = 0。