added vec.js

1 files changed, 26 insertions, 0 deletions

diff --git a/utils/vec.js b/utils/vec.js
new file mode 100644
index 0000000..9808c8b
--- /dev/null
+++ b/utils/vec.js
@@ -0,0 +1,26 @@
+// A utility library for vector (coordinate) operations.
+
+exports.mult = function(vec, scal){
+  for (let i = 0; i < vec.length; i++)
+    vec[i] = scal*vec[i];
+  return vec;
+}
+
+function elem(orig, vec, op){
+  let comb = [];
+  for (let i = 0; i < orig.length; i++){
+    comb.push(op(vec[i],orig[i]));
+  }
+  return comb;
+}
+exports.elem = elem;
+
+exports.add = function(orig, vec){
+  return elem(orig, vec, (a,b) => a+b);
+}
+exports.sub = function(orig, vec){
+  return elem(orig, vec, (a,b) => a-b);
+}
+exports.dot = function(orig,vec){
+  return elem(orig, vec, (a,b) => a*b);
+}