Akshay Shirahatti

Hi, I'm sorry about that CSV file . The USL should be 8 and LSL should be 7,.25. I think I'm stuck with the standard deviation part. I'm getting NaN for Std deviation. I checked with the calculator. I need to get 2.57 as Cp

Hi, I'm not getting the correct Cp,Cpk values. I'm using C# to calculate cp cpk for the input test file which is in CSV format (attached). Here is my full code using Microsoft.VisualBasic.FileIO; using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Data.OleDb; using System.Drawing; using System.IO; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows.Forms; namespace _1.CSV { public partial class Form1 : Form { public Form1() { InitializeComponent(); } DataTable dt = new DataTable(); private void button1_Click(object sender, EventArgs e) { OpenFileDialog openFileDialog1 = new OpenFileDialog(); openFileDialog1.Filter = ("comma seperated value | *.CSV"); if (openFileDialog1.ShowDialog() == DialogResult.OK) { string strfilename = openFileDialog1.FileName; if (File.Exists(strfilename)) { textBox1.Text = strfilename; } else { strfilename = ""; } if (!string.IsNullOrWhiteSpace(strfilename)) { textBox1.Text = strfilename; } else { MessageBox.Show("Please select a file"); } } else { MessageBox.Show("Please select a file"); } } private void button2_Click(object sender, EventArgs e) { dt = GetDataTabletFromCSVFile(textBox1.Text); foreach (DataRow row in dt.Rows) { if (Convert.ToDateTime(row["Date"]) <= Convert.ToDateTime(dateTimePicker2.Text) && Convert.ToDateTime(row["Date"]) >= Convert.ToDateTime(dateTimePicker1.Text)) { double sum = 0; double sumsq = 0; foreach (DataRow Row in dt.Rows) { Double delta = double.Parse(row["USL"].ToString()) - Double.Parse(row["LSL"].ToString()); sum += delta; sumsq += delta * delta; } double mean = sum / dt.Rows.Count; double stdev = Math.Sqrt(sumsq / dt.Rows.Count - mean * mean); Double usl = Convert.ToDouble(row["USL"]); Double lsl = Convert.ToDouble(row["LSL"]); double Cp = (usl - lsl) / (6 * stdev); double Cpk = Math.Min( (usl - mean) / (3 * stdev), (mean - lsl) / (3 * stdev) ); Console.WriteLine( "{0}: {1},{2}, {3}, {4}", row["Date"], usl, lsl, Cp, Cpk); button2.Enabled = false; } } } private static DataTable GetDataTabletFromCSVFile(string csv_file_path) { DataTable csvData = new DataTable(); try { using (TextFieldParser csvReader = new TextFieldParser(csv_file_path)) { csvReader.SetDelimiters(new string[] { "," }); csvReader.HasFieldsEnclosedInQuotes = true; string[] colFields = csvReader.ReadFields(); foreach (string column in colFields) { if (column == "Date" || column == "Test1" || column == "USL" || column == "LSL") { DataColumn datecolumn = new DataColumn(column); datecolumn.AllowDBNull = true; csvData.Columns.Add(datecolumn); } } while (!csvReader.EndOfData) { string[] fieldData = csvReader.ReadFields(); for (int i = 0; i < fieldData.Length; i++) { if (fieldData == "") { fieldData = null; } } csvData.Rows.Add(fieldData); } } } catch (Exception) { throw; } return csvData; } } } csvdemo1.csv