Calculate GDP

# the order is Dairy, Coffee, and Flower
p1 = c(10, 20, 20)
q1 = c(80, 150, 200)
p2 = c(16, 20, 28)
q2 = c(85, 165, 150)
p3 = c(20, 35, 20)
q3 = c(85, 165, 200)

Price as a Fisher index

# Calculate chain Weight
P_t_t1 = function(pt, qt, pt1, qt1) {
    sqrt((pt1 %*% qt) * (pt1 %*% qt1)/(pt %*% qt)/(pt %*% qt1))
}

# Period 1 to 2 P_1_2= P_t_t1(p1,q1,p2,q2)
P_2_3 = P_t_t1(p2, q2, p3, q3)
P_2_3

##      [,1]
## [1,] 1.15

Quantity as a Fisher index

# Calculate chain Weight
Q_t_t1 = function(pt, qt, pt1, qt1) {
    sqrt((pt %*% qt1) * (pt1 %*% qt1)/(pt %*% qt)/(pt1 %*% qt))
}

# Period 1 to 2
Q_1_2 = Q_t_t1(p1, q1, p2, q2)
Q_1_2

##        [,1]
## [1,] 0.9067

# Period 2 to 3
Q_2_3 = Q_t_t1(p2, q2, p3, q3)
Q_2_3

##       [,1]
## [1,] 1.126

realGDP1 = 1
realGDP2 = realGDP1 * Q_1_2
realGDP2

##        [,1]
## [1,] 0.9067

realGDP3 = realGDP2 * Q_2_3
realGDP3

##       [,1]
## [1,] 1.021

Nominal GDP and GDP deflator

GDP_3 = 6300/realGDP3 * 100
GDP_3

##        [,1]
## [1,] 616936