/** This tests the least-squares fitting routines in LeastSquares.frink */

use LeastSquares.frink
use Grid.frink

allpoints = new array
for line= lines["file:/home/eliasen/prog/webroot/images/alc.txt"]
{
   points = split[%r/\s+/, line]

   // This gives alcohol percentage by volume to density.
   // Remove the reverse to give density to percentage by volume.  For example:
   //allpoints.push[mul[eval[points], [g/cm^3, percent]]]
   allpoints.push[reverse[eval[points]]]
}

println["allpoints is $allpoints"]


// Fit the values to a polynomial of the specified degree
[bestf, bestr] = LeastSquares.fitDegreePiecewise3[allpoints, 3]

//println[ls.toMatrix[].formatMatrix[]]
//symbolicMode[true]
//println[ls.toExpression[]]

println[inputForm[bestf]]
println["r-value is $bestr"]

g = new graphics
p = new polyline
dummyX =!= dummyX
dummyY =!= dummyY
for [density, abv] = sort[allpoints, byColumn[0]]
{
   g.fillEllipseCenter[abv dummyX,-density dummyY, 0.3 dummyX, 0.001 dummyY]
   p.addPoint[bestf[density] dummyX, -density dummyY]
}

g.color[0,0,1]
g.add[p]
grid = new Grid
grid.setUnits[dummyX, -dummyY]
grid.auto[g]
g.add[grid.getGrid[]]

g.show[]