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Task/Vector-products/REXX/vector-products.rexx

@@ -0,0 +1,29 @@
+/*REXX program computes the products:    the  dot          product,     */
+/*                                       the cross         product,     */
+/*                                       the scalar triple product,  and*/
+/*                                       the vector triple product.     */
+
+a =   3   4   5                        /*positive numbers don't need  " */
+b =   4   3   5
+c = "-5 -12 -13"
+
+call tellV 'vector A =',a              /*show the  A  vector, aligned #s*/
+call tellV 'vector B =',b              /*show the  B  vector, aligned #s*/
+call tellV 'vector C =',c              /*show the  C  vector, aligned #s*/
+say
+call tellV '  dot product [A∙B] =',dot(a,b)
+call tellV 'cross product [AxB] =',cross(a,b)
+call tellV 'scalar triple product [A∙(BxC)] =',dot(a,cross(b,c))
+call tellV 'vector triple product [Ax(BxC)] =',cross(a,cross(b,c))
+exit                                   /*stick a fork in it, we're done.*/
+/*─────────────────────────────────────cross subroutine─────────────────*/
+cross: procedure; parse arg x1 x2 x3,y1 y2 y3       /*the CROSS product.*/
+       return x2*y3-x3*y2 x3*y1-x1*y3 x1*y2-x2*y1   /*a vector quantity.*/
+/*─────────────────────────────────────dot subroutine───────────────────*/
+dot: procedure; parse arg x1 x2 x3,y1 y2 y3         /*the  DOT  product.*/
+     return x1*y1 + x2*y2 + x3*y3                   /*a scaler quantity.*/
+/*─────────────────────────────────────tellV subroutine─────────────────*/
+tellV: procedure; parse arg name,x y z              /*display the vector*/
+       w=max(4,length(x),length(y),length(z))       /*max width of nums.*/
+       say right(name,40) right(x,w) right(y,w) right(z,w)
+       return