Vector products: Difference between revisions

<syntaxhighlight lang="rexx">/*REXX program computes the products: dot, cross, scalar triple, and vector triple.*/

a= 3 4 5

b= 4 3 5 /*(positive numbers don't need quotes.)*/

c= "-5 -12 -13"

call tellV 'vector A =', a /*show the A vector, aligned numbers.*/

call tellV 'vector B =', b /* " " B " " " */

call tellV 'vector C =', c /* " " C " " " */

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 0 /*stick a fork in it, we're all done. */

/*──────────────────────────────────────────────────────────────────────────────────────*/

cross: procedure; arg $1 $2 $3,@1 @2 @3; return $2*@3 -$3*@2 $3*@1 -$1*@3 $1*@2 -$2*@1

dot: procedure; arg $1 $2 $3,@1 @2 @3; return $1*@1 + $2*@2 + $3*@3

/*──────────────────────────────────────────────────────────────────────────────────────*/

tellV: procedure; parse arg name,x y z; w=max(4,length(x),length(y),length(z)) /*max W*/

say right(name,40) right(x,w) right(y,w) right(z,w); /*show vector.*/ return</syntaxhighlight>

{{out|output|text=&nbsp; when using the default internal inputs:}}

vector A = 3 4 5

vector B = 4 3 5

vector C = -5 -12 -13

dot product [A∙B] = 49

cross product [AxB] = 5 5 -7

scalar triple product [A∙(BxC)] = 6

vector triple product [Ax(BxC)] = -267 204 -3

</pre>