June 2018 Update

Task/Vector-products/Factor/vector-products.factor

@@ -0,0 +1,31 @@
+USING: arrays io locals math prettyprint sequences ;
+IN: rosetta-code.vector-products
+
+: dot-product ( a b -- dp ) [ * ] 2map sum ;
+
+:: cross-product ( a b -- cp )
+    a first :> a1 a second :> a2 a third :> a3
+    b first :> b1 b second :> b2 b third :> b3
+    a2 b3 * a3 b2 * - ! X
+    a3 b1 * a1 b3 * - ! Y
+    a1 b2 * a2 b1 * - ! Z
+    3array ;
+
+: scalar-triple-product ( a b c -- stp )
+    cross-product dot-product ;
+
+: vector-triple-product ( a b c -- vtp )
+    cross-product cross-product ;
+
+[let
+    { 3 4 5 }      :> a
+    { 4 3 5 }      :> b
+    { -5 -12 -13 } :> c
+    "a: " write a .
+    "b: " write b .
+    "c: " write c . nl
+    "a . b: " write a b dot-product .
+    "a x b: " write a b cross-product .
+    "a . (b x c): " write a b c scalar-triple-product .
+    "a x (b x c): " write a b c vector-triple-product .
+]

Task/Vector-products/Julia/vector-products.julia

@@ -1,26 +1,20 @@
-function scltrip{T<:Number}(a::AbstractArray{T,1},
-                            b::AbstractArray{T,1},
-                            c::AbstractArray{T,1})
-    dot(a, cross(b, c))
+function scalarproduct(a::AbstractVector{T}, b::AbstractVector{T}, c::AbstractVector{T}) where {T<:Number}
+    return dot(a, cross(b, c))
 end
 
-function vectrip{T<:Number}(a::AbstractArray{T,1},
-                            b::AbstractArray{T,1},
-                            c::AbstractArray{T,1})
-    cross(a, cross(b, c))
+function vectorproduct(a::AbstractVector{T}, b::AbstractVector{T}, c::AbstractVector{T}) where {T<:Number}
+    return cross(a, cross(b, c))
 end
 
-a = [3, 4, 5]
-b = [4, 3, 5]
-c = [-5, -12, -13]
+const a = [3, 4, 5]
+const b = [4, 3, 5]
+const c = [-5, -12, -13]
 
 println("Test Vectors:")
-println("   a = ", a)
-println("   b = ", a)
-println("   c = ", a)
+@show a b c
 
 println("\nVector Products:")
-println("   a dot b = ", dot(a, b))
-println("   a cross b = ", cross(a, b))
-println("   a dot b cross c = ", scltrip(a, b, c))
-println("   a cross b cross c = ", vectrip(a, b, c))
+@show dot(a, b)
+@show cross(a, b)
+@show scalarproduct(a, b, c)
+@show vectorproduct(a, b, c)

Task/Vector-products/Modula-2/vector-products.mod2

@@ -0,0 +1,83 @@
+MODULE VectorProducts;
+FROM RealStr IMPORT RealToStr;
+FROM Terminal IMPORT WriteString,WriteLn,ReadChar;
+
+PROCEDURE WriteReal(r : REAL);
+VAR buf : ARRAY[0..31] OF CHAR;
+BEGIN
+    RealToStr(r, buf);
+    WriteString(buf)
+END WriteReal;
+
+TYPE Vector = RECORD
+    a,b,c : REAL;
+END;
+
+PROCEDURE Dot(u,v : Vector) : REAL;
+BEGIN
+    RETURN u.a * v.a
+         + u.b * v.b
+         + u.c * v.c
+END Dot;
+
+PROCEDURE Cross(u,v : Vector) : Vector;
+BEGIN
+    RETURN Vector{
+        u.b*v.c - u.c*v.b,
+        u.c*v.a - u.a*v.c,
+        u.a*v.b - u.b*v.a
+    }
+END Cross;
+
+PROCEDURE ScalarTriple(u,v,w : Vector) : REAL;
+BEGIN
+    RETURN Dot(u, Cross(v, w))
+END ScalarTriple;
+
+PROCEDURE VectorTriple(u,v,w : Vector) : Vector;
+BEGIN
+    RETURN Cross(u, Cross(v, w))
+END VectorTriple;
+
+PROCEDURE WriteVector(v : Vector);
+BEGIN
+    WriteString("<");
+    WriteReal(v.a);
+    WriteString(", ");
+    WriteReal(v.b);
+    WriteString(", ");
+    WriteReal(v.c);
+    WriteString(">")
+END WriteVector;
+
+VAR a,b,c : Vector;
+BEGIN
+    a := Vector{3.0, 4.0, 5.0};
+    b := Vector{4.0, 3.0, 5.0};
+    c := Vector{-5.0, -12.0, -13.0};
+
+    WriteVector(a);
+    WriteString(" dot ");
+    WriteVector(b);
+    WriteString(" = ");
+    WriteReal(Dot(a,b));
+    WriteLn;
+
+    WriteVector(a);
+    WriteString(" cross ");
+    WriteVector(b);
+    WriteString(" = ");
+    WriteVector(Cross(a,b));
+    WriteLn;
+
+    WriteVector(a);
+    WriteString(" cross (");
+    WriteVector(b);
+    WriteString(" cross ");
+    WriteVector(c);
+    WriteString(") = ");
+    WriteVector(VectorTriple(a,b,c));
+    WriteLn;
+
+    ReadChar
+END VectorProducts.