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rcurve

Multiply two curves with different x values using R

I have two typical (x,y(x)) curves. The two of them expand over a similar x range but have different "resolution". This is, while one of the will cover an x range with 300 x-values the second curve has 3200 values for aproximately the same range.

I want to multiply the two curves (curve1 * curve 2) so that the data in curve2 is mapped onto the data in curve1.

How one can do this in R. In case is useful, x values are always monotonically increasing.

Solution

  • Let's say your curves are two arrays c1 and c2 known on the discretization points x1 and x2.

    You should do the following to have the curve 2 on the x-values of curve 1:

    c2.modified <- approx(x2, c2, x1)

    Then you just multiply:

    c2.modified * c1