示例#1
0
        public void TestInterpolationPointReplacement()
        {
            IWriteableInterpolable interp  = new SmallDoubleInterpolable(2);
            IInterpolable          interp2 = (IInterpolable)interp;

            interp.SetYValue(3.3, 6.6);
            interp.SetYValue(4.4, 8.8);
            interp.SetYValue(7.7, 12.8);
            interp.SetYValue(13.2, 22.8);

            interp.SetYValue(7.7, 17.8);
            Verify(interp2, 8.8, 18.8);
        }
示例#2
0
        public void TestInterpolationFrom2Points()
        {
            IWriteableInterpolable interp  = new SmallDoubleInterpolable(2);
            IInterpolable          interp2 = (IInterpolable)interp;

            interp.SetYValue(3.3, 6.6);
            interp.SetYValue(4.4, 8.8);

            Verify(interp2, 5.5, 11);
            Verify(interp2, 4.4, 8.8);
            Verify(interp2, 3.85, 7.7);
            Verify(interp2, 3.3, 6.6);
            Verify(interp2, 2.2, 4.4);
            Verify(interp2, 0.0, 0.0);
            Verify(interp2, -2.2, -4.4);
        }
示例#3
0
        public void TestInterpolationFrom4Points()
        {
            IWriteableInterpolable interp  = new SmallDoubleInterpolable(4);
            IInterpolable          interp2 = (IInterpolable)interp;

            interp.SetYValue(4.8, 2.7);
            interp.SetYValue(3.2, 1.5);
            interp.SetYValue(6.0, 4.5);
            interp.SetYValue(0.8, 0.6);

            Verify(interp2, 7.2, 6.3);
            Verify(interp2, 6.0, 4.5);
            Verify(interp2, 5.2, 3.3);
            Verify(interp2, 4.8, 2.7);
            Verify(interp2, 4.0, 2.1);
            Verify(interp2, 3.2, 1.5);
            Verify(interp2, 1.6, 0.9);
            Verify(interp2, 0.8, 0.6);
            Verify(interp2, 0.0, 0.3);
            Verify(interp2, -0.8, 0.0);
        }
示例#4
0
        /// <summary>
        /// Given a list of source items, and a function that returns a double value for each, this
        /// method ascertains the double value that represents the given percentile in that population.
        /// For example, given a list of students, and a function that returns their grades, this method
        /// will return the grade that represents the 50th percentile across that population of students.
        /// </summary>
        /// <typeparam name="T">The type of items in the list of source items.</typeparam>
        /// <param name="srcItems">The source items for which we want to know the percentile.</param>
        /// <param name="percentile">The percentile on the interval [0.0, 100.0] at which we seek the value from the source items.</param>
        /// <param name="valueGetter">The function that ascertains the value of each source item.</param>
        /// <param name="interpolate">if set to <c>true</c>, we interpolate between located items' values.</param>
        /// <returns></returns>
        public static double GetValueAtPercentile <T>(this List <T> srcItems, double percentile, Func <T, double> valueGetter, bool interpolate)
        {
            _Debug.Assert(srcItems.Count > 0, "Percentile was requested from a population of zero items. Percentile source populations must have at least one member.");
            _Debug.Assert(percentile >= 0.0 && percentile <= 100.0, string.Format("Percentile was requested as {0} - it must be a double on the interval [0.0 ... 100.0]", percentile));
            percentile = percentile / 100.0;
            if (srcItems.Count == 1)
            {
                return(valueGetter(srcItems[0]));
            }
            else
            {
                srcItems.Sort((t1, t2) => Comparer <double> .Default.Compare(valueGetter(t1), valueGetter(t2)));

                double index  = (srcItems.Count - 1) * percentile;
                double lowNdx = Math.Floor(index);
                double hiNdx  = Math.Ceiling(index);
                if (lowNdx == hiNdx)
                {
                    if (lowNdx == 0)
                    {
                        hiNdx++;
                    }
                    else
                    {
                        lowNdx--;
                    }
                }
                double lowVal = valueGetter(srcItems[(int)lowNdx]);
                double hiVal  = valueGetter(srcItems[(int)hiNdx]);
                if (interpolate)
                {
                    SmallDoubleInterpolable sdi = new SmallDoubleInterpolable(new[] { lowNdx, hiNdx }, new[] { lowVal, hiVal });
                    return(sdi.GetYValue(index));
                }
                else
                {
                    return((index - lowNdx) < 0.5 ? lowVal : hiVal);
                }
            }
        }