Polynomial regression: Difference between revisions
→{{header|Maple}}
SqrtNegInf (talk | contribs) m (→{{header|Perl}}: oops, use feature 'say') |
|||
Line 1,066:
10 321 321.0
</pre>
=={{header|Lua}}==
{{trans|Modula-2}}
<lang lua>function eval(a,b,c,x)
return a + (b + c * x) * x
end
function regression(xa,ya)
local n = #xa
local xm = 0.0
local ym = 0.0
local x2m = 0.0
local x3m = 0.0
local x4m = 0.0
local xym = 0.0
local x2ym = 0.0
for i=1,n do
xm = xm + xa[i]
ym = ym + ya[i]
x2m = x2m + xa[i] * xa[i]
x3m = x3m + xa[i] * xa[i] * xa[i]
x4m = x4m + xa[i] * xa[i] * xa[i] * xa[i]
xym = xym + xa[i] * ya[i]
x2ym = x2ym + xa[i] * xa[i] * ya[i]
end
xm = xm / n
ym = ym / n
x2m = x2m / n
x3m = x3m / n
x4m = x4m / n
xym = xym / n
x2ym = x2ym / n
local sxx = x2m - xm * xm
local sxy = xym - xm * ym
local sxx2 = x3m - xm * x2m
local sx2x2 = x4m - x2m * x2m
local sx2y = x2ym - x2m * ym
local b = (sxy * sx2x2 - sx2y * sxx2) / (sxx * sx2x2 - sxx2 * sxx2)
local c = (sx2y * sxx - sxy * sxx2) / (sxx * sx2x2 - sxx2 * sxx2)
local a = ym - b * xm - c * x2m
print("y = "..a.." + "..b.."x + "..c.."x^2")
for i=1,n do
print(string.format("%2d %3d %3d", xa[i], ya[i], eval(a, b, c, xa[i])))
end
end
local xa = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
local ya = {1, 6, 17, 34, 57, 86, 121, 162, 209, 262, 321}
regression(xa, ya)</lang>
{{out}}
<pre>y = 1 + 2x + 3x^2
0 1 1
1 6 6
2 17 17
3 34 34
4 57 57
5 86 86
6 121 121
7 162 162
8 209 209
9 262 262
10 321 321</pre>
=={{header|Maple}}==
| |||