added method for checking linear dependence

index.js

@@ -234,7 +234,15 @@ void function(root){
 
     }
 
-    function invert(matrix){
+    function spanning(matrix){
+        var size = Math.max(matrix.length, matrix[0].length)
+          , target = fully_reduce(matrix.filter(function(row, i){ return i < size })
+                            .map(function(row){
+                                return row.filter(function(col, i){
+                                    return i < size
+                                })
+                            }))
+        return is_identity(target[0])
     }
 
     function vatrix(arr){ return arr.map(m) }
@@ -268,6 +276,7 @@ void function(root){
     vatrix.rowReduce = fully_reduce
     vatrix.mrr = fully_reduce
 
+    vatrix.isSpanning = spanning
     vatrix.drawMatrix = draw_matrix
     vatrix.isLowerTriangular = is_lower_triangular
     vatrix.isUpperTriangular = is_upper_triangular

package.json

@@ -1,7 +1,7 @@
 {
   "name": "vatrix",
   "description": "matrix tools",
-  "version": "0.0.3",
+  "version": "0.0.4",
   "scripts": {
     "test": "mocha",
     "prepublish": "npm test"

test/test.js

@@ -163,7 +163,15 @@ describe('vectors', function(){
                     ,[r(35421),r(-182516),r(211537)]
                 ]), r(154363999) ))
             test([[32, 551, 23], [111, 391, 12], [122, 123, 2], [332, 13, 832]])
+            test([[2, 2, 2, 2], [2, -2, 2, -2]])
         })
 
     })
+
+    describe('spanning set', function(){
+        it('returns true if the matrix is spanning', function(){
+            expect(vatrix.isSpanning(vatrix([[1,2,-1],[2,0,4],[-1,1,3]]))).to.be(true)
+            expect(vatrix.isSpanning(vatrix([[1,2,-1,3],[2,-1,8,1],[-3,4,17,1]]))).to.be(false)
+        })
+    })
 })