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Task/Vector-products/Phix/vector-products.phix

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+function dot_product(sequence a, b)
+    return sum(sq_mul(a,b))
+end function
+
+function cross_product(sequence a, b)
+integer {a1,a2,a3} = a, {b1,b2,b3} = b
+    return {a2*b3-a3*b2, a3*b1-a1*b3, a1*b2-a2*b1}
+end function
+
+function scalar_triple_product(sequence a, b, c)
+    return dot_product(a,cross_product(b,c))
+end function
+
+function vector_triple_product(sequence a, b, c)
+    return cross_product(a,cross_product(b,c))
+end function
+
+constant a = {3, 4, 5}, b = {4, 3, 5}, c = {-5, -12, -13}
+
+puts(1,"      a . b = ")    ?dot_product(a,b)
+puts(1,"      a x b = ")    ?cross_product(a,b)
+puts(1,"a . (b x c) = ")    ?scalar_triple_product(a,b,c)
+puts(1,"a x (b x c) = ")    ?vector_triple_product(a,b,c)