def METHOD_NAME(sdev, corr, k1, k2, k3):
    grass.debug(_("Calculating OIF for combination: %s, %s, %s" % (k1, k2, k3)), 1)
    # calculate SUM of Stddeviations:
    ssdev = [sdev[k1], sdev[k2], sdev[k3]]
    numer = sum(ssdev)
    # calculate SUM of absolute(Correlation values):
    scorr = [corr[k1, k2], corr[k1, k3], corr[k2, k3]]
    denom = sum(map(abs, scorr))
    # Calculate OIF index:
    #     Divide (SUM of Stddeviations) and (SUM of Correlation)
    return numer / denom