36 lines
1.2 KiB
Text
36 lines
1.2 KiB
Text
import "./math" for Nums
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import "./seq" for Lst
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import "./fmt" for Fmt
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var polynomialRegression = Fn.new { |x, y|
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var xm = Nums.mean(x)
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var ym = Nums.mean(y)
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var x2m = Nums.mean(x.map { |e| e * e })
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var x3m = Nums.mean(x.map { |e| e * e * e })
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var x4m = Nums.mean(x.map { |e| e * e * e * e })
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var z = Lst.zip(x, y)
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var xym = Nums.mean(z.map { |p| p[0] * p[1] })
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var x2ym = Nums.mean(z.map { |p| p[0] * p[0] * p[1] })
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var sxx = x2m - xm * xm
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var sxy = xym - xm * ym
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var sxx2 = x3m - xm * x2m
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var sx2x2 = x4m - x2m * x2m
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var sx2y = x2ym - x2m * ym
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var b = (sxy * sx2x2 - sx2y * sxx2) / (sxx * sx2x2 - sxx2 * sxx2)
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var c = (sx2y * sxx - sxy * sxx2) / (sxx * sx2x2 - sxx2 * sxx2)
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var a = ym - b * xm - c * x2m
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var abc = Fn.new { |xx| a + b * xx + c * xx * xx }
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System.print("y = %(a) + %(b)x + %(c)x^2\n")
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System.print(" Input Approximation")
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System.print(" x y y1")
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for (p in z) Fmt.print("$2d $3d $5.1f", p[0], p[1], abc.call(p[0]))
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}
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var x = List.filled(11, 0)
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for (i in 1..10) x[i] = i
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var y = [1, 6, 17, 34, 57, 86, 121, 162, 209, 262, 321]
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polynomialRegression.call(x, y)
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