某些值導致無限循環

Question

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我正在嘗試構建一個用於能量計算的Javascript計算器，它通常可以正常工作，但是某些數字會導致瀏覽器標簽崩潰。 我的jsfiddle：

http://jsfiddle.net/qdjfrjLr/

嘗試在一天的放電時間內輸入8，或者在任何時間輸入15。

我懷疑問題與我的循環有關（在“執行循環”注釋下），但我看不到問題。 循環的目的是確定liq_capacity需要什么值才能使fri_ending_balance達到（或接近）0。

function calculate() {
    // user inputs
    var sat_charge = parseInt(document.getElementById('sat_charge').value);
    var sat_discharge = parseInt(document.getElementById('sat_discharge').value);
    var sun_charge = parseInt(document.getElementById('sun_charge').value);
    var sun_discharge = parseInt(document.getElementById('sun_discharge').value);
    var mon_charge = parseInt(document.getElementById('mon_charge').value);
    var mon_discharge = parseInt(document.getElementById('mon_discharge').value);
    var tue_charge = parseInt(document.getElementById('tue_charge').value);
    var tue_discharge = parseInt(document.getElementById('tue_discharge').value);
    var wed_charge = parseInt(document.getElementById('wed_charge').value);
    var wed_discharge = parseInt(document.getElementById('wed_discharge').value);
    var thu_charge = parseInt(document.getElementById('thu_charge').value);
    var thu_discharge = parseInt(document.getElementById('thu_discharge').value);
    var fri_charge = parseInt(document.getElementById('fri_charge').value);
    var fri_discharge = parseInt(document.getElementById('fri_discharge').value);
    // back-end variables
    var sys_power_rating = 100;
    var noak = 1;
    var efficiency = 60; // expressed as a percentage
    var tank_escalation_factor = 0.9;
    var liq_reference_cost = 16300000;
    var experience_coefficient = 0.175; // expressed as a decimal
    var liq_reference_size = 300;
    var liq_and_pru_escalation_factor = 0.6;
    var power_recovery_reference_cost = 5705000;
    var power_recovery_reference_size = 3.5;
    var tank_coldstore_reference_size = 100;
    var liq_plant_specific_work = 0.2;
    var cost_of_tank_and_coldstore = 41;
    var pru_specific_work = liq_plant_specific_work * (efficiency / 100);
    if (liq_plant_specific_work < 0.1) {
        var tank_coldstore_reference_cost = cost_of_tank_and_coldstore * tank_coldstore_reference_size * liq_plant_specific_work;
    } else {
        var tank_coldstore_reference_cost = cost_of_tank_and_coldstore * tank_coldstore_reference_size * 0.1;
    }
    // do the loop
    var liq_capacity = 1;
    var fri_ending_balance = 1;
    while (fri_ending_balance < -0.1 || fri_ending_balance > 0.1) {
        var sat_initial_balance = 0;
        var sat_production = sat_charge * liq_capacity / 24;
        var sat_consumption = -1 * sat_discharge * sys_power_rating / pru_specific_work;
        var sat_ending_balance = sat_initial_balance + sat_production + sat_consumption;
        var sun_initial_balance = sat_ending_balance;
        var sun_production = sun_charge * liq_capacity / 24;
        var sun_consumption = -1 * sun_discharge * sys_power_rating / pru_specific_work;
        var sun_ending_balance = sun_initial_balance + sun_production + sun_consumption;
        var mon_initial_balance = sun_ending_balance;
        var mon_production = mon_charge * liq_capacity / 24;
        var mon_consumption = -1 * mon_discharge * sys_power_rating / pru_specific_work;
        var mon_ending_balance = mon_initial_balance + mon_production + mon_consumption;
        var tue_initial_balance = mon_ending_balance;
        var tue_production = tue_charge * liq_capacity / 24;
        var tue_consumption = -1 * tue_discharge * sys_power_rating / pru_specific_work;
        var tue_ending_balance = tue_initial_balance + tue_production + tue_consumption;
        var wed_initial_balance = tue_ending_balance;
        var wed_production = wed_charge * liq_capacity / 24;
        var wed_consumption = -1 * wed_discharge * sys_power_rating / pru_specific_work;
        var wed_ending_balance = wed_initial_balance + wed_production + wed_consumption;
        var thu_initial_balance = wed_ending_balance;
        var thu_production = thu_charge * liq_capacity / 24;
        var thu_consumption = -1 * thu_discharge * sys_power_rating / pru_specific_work;
        var thu_ending_balance = thu_initial_balance + thu_production + thu_consumption;
        var fri_initial_balance = thu_ending_balance;
        var fri_production = fri_charge * liq_capacity / 24;
        var fri_consumption = -1 * fri_discharge * sys_power_rating / pru_specific_work;
        fri_ending_balance = fri_initial_balance + fri_production + fri_consumption;
        liq_capacity = liq_capacity + 0.1;
    }
    var power_input = liq_capacity / 24 * liq_plant_specific_work;
    var liq_store_capacity_tonnes = Math.max(sat_production, sat_ending_balance, sun_production, sun_ending_balance, mon_production, mon_ending_balance, tue_production, tue_ending_balance, wed_production, wed_ending_balance, thu_production, thu_ending_balance, fri_production, fri_ending_balance);
    var liq_store_capacity_mwh = sys_power_rating * Math.max(sat_discharge, sun_discharge, mon_discharge, tue_discharge, wed_discharge, thu_discharge, fri_discharge);
    var liq_store_capacity_mwh_effective = tank_coldstore_reference_size * pru_specific_work;
    var liq_ecurve = liq_reference_cost * (Math.pow(noak, (Math.log(1-experience_coefficient)/Math.log(2))));
    var pru_ecurve = power_recovery_reference_cost * (Math.pow(noak, (Math.log(1-experience_coefficient)/Math.log(2))));
    var tank_and_coldstore_ecurve = tank_coldstore_reference_cost;
    var liq_cost_dollars = liq_ecurve * Math.pow((liq_capacity / liq_reference_size), liq_and_pru_escalation_factor);
    var pru_cost_dollars = pru_ecurve * Math.pow((sys_power_rating / power_recovery_reference_size), liq_and_pru_escalation_factor);
    var tank_and_coldstore_cost_dollars = (tank_and_coldstore_ecurve * 1000) * Math.pow((liq_store_capacity_tonnes / tank_coldstore_reference_size), tank_escalation_factor);
    var capex = liq_cost_dollars + pru_cost_dollars + tank_and_coldstore_cost_dollars;
    var cost_kw = capex / (sys_power_rating * 1000);
    var cost_kwh = capex / (liq_store_capacity_mwh * 1000);
    // slap those results on the page
    document.getElementById('liq_capacity').value = (liq_capacity).toFixed(0);
    document.getElementById('power_input').value = (power_input).toFixed(2);
    document.getElementById('liq_store_capacity_mwh').value = (liq_store_capacity_mwh).toFixed(0);
    document.getElementById('efficiency').value = efficiency + '%';
    document.getElementById('capex').value = (capex / 1000000).toFixed(1);
    document.getElementById('cost_kw').value = (cost_kw).toFixed(2);
    document.getElementById('cost_kwh').value = (cost_kwh).toFixed(2);
}

Answer 1

喏，給你。 相當多（我實際上從我的實際內容中刪除了很多東西），所以不想讓頁面過於混亂，因此jsfiddle :-)

編輯：很抱歉以錯誤的方式發布-我只是使用訪客帳戶在此處詢問問題！ 這樣至少意味着我的初始帖子不會變得異常龐大。

（代碼轉儲添加到問題。）

編輯：非常感謝w3d！ 愚蠢的是，我過去的可接受結果范圍更廣（-0.9到0.9），但是為了獲得更准確的結果而對其進行了更改。 無論如何，現在一切都運行良好，所以謝謝您的幫助:-)不，沒有電子郵件通知！ 我只是不時刷新。

Answer 2

是的，問題出在您的循環中：

while (fri_ending_balance < -0.1 || fri_ending_balance > 0.1) {

如果將“ Discharge”（放電）天的值指定為9 ，則fri_ending_balance的值永遠不會接近0來滿足循環條件。 具體來說， fri_ending_balance永遠不會變為> = -0.1和<= 0.1，因此循環永遠不會結束。

如果將這些結果記錄到控制台，則可以看到發生了什么：

Iteration  fri_ending_balance
71418      -0.5999999802772891
71419      -0.36666664694234896
71420      -0.1333333136069541    /* Should stop here */
71421       0.10000001972525752
71422       0.3333333530601976
71423       0.5666666863955925
71424       0.8000000197278041