lib/muflax/math.rb in muflax-0.5.0 vs lib/muflax/math.rb in muflax-0.5.1

@@ -33,7 +33,25 @@
     end
 
     def choose k, n
       Math.factorial(n) / (Math.factorial(k) * Math.factorial(n - k))
     end
+
+    def mass_index coeff, mass, height, adjustment=1.0
+      h /= 100.0 if (50..300).include? h # cm -> m auto-correction
+      adjustment * (mass / (height ** coeff))
+    end
+
+    def mass_index_at coeff, index, height, adjustment=1.0
+      h /= 100.0 if (50..300).include? h # cm -> m auto-correction
+      index * (height ** coeff) / adjustment
+    end
+
+    def bmi    	m, h	; mass_index 2.0, m, h     	; end
+    def bmi_adj	m, h	; mass_index 2.5, m, h, 1.3	; end
+    def bsi    	m, h	; mass_index 3.0, m, h     	; end
+
+    def bmi_at    	i, h	; mass_index_at 2.0, i, h     	; end
+    def bmi_adj_at	i, h	; mass_index_at 2.5, i, h, 1.3	; end
+    def bsi_at    	i, h	; mass_index_at 3.0, i, h     	; end
   end
 end