NDP {MetCirc} | R Documentation |
Calculate the normalised dot product (NDP)
NDP(matrow1, matrow2, m = 0.5, n = 2, mass)
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The NDP is calculated according to the following formula:
∑(W_{S1, i} \cdot W_{S2, i}) ^ 2 ∑(W_{S1, i} ^ 2) * ∑(W_{S2, i} ^ 2)
, with W = [ peak intensity] ^{m} \cdot [m/z]^n. For further information see Li et al. (2015): Navigating natural variation in herbivory-induced secondary metabolism in coyote tobacco populations using MS/MS structural analysis. PNAS, E4147–E4155. NDP returns a numeric value ranging between 0 and 1, where 0 indicates no similarity between the two MS/MS features, while 1 indicates that the MS/MS features are identical. For the calculation of the NDP only the elements of S1 and S2 that are not equal to 0 will be used.
NDP returns a numeric similarity coefficient between 0 and 1
Thomas Naake, thomasnaake@googlemail.com
data("binnedMSP", package = "MetCirc") NDP(matrow1 = binnedMSP[1,], matrow2 = binnedMSP[2,], m = 0.5, n = 2, mass = colnames(binnedMSP))