Merge pull request #440 from rjbaucells/develop

Fix for issue #437 (Possible bug in lusolve)
josdejong · Aug 28, 2015 · 08ccb24 · 08ccb24
2 parents 3b80df8 + 06c3cd3
commit 08ccb24
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Showing 5 changed files with 39 additions and 24 deletions.
diff --git a/lib/function/algebra/decomposition/lup.js b/lib/function/algebra/decomposition/lup.js
@@ -211,12 +211,16 @@ function factory (type, config, load, typed) {
     var u =  new DenseMatrix({
       data: udata,
       size: usize
-    });    
+    });
+    // p vector
+    var pv = [];
+    for (i = 0, n = p.length; i < n; i++)
+      pv[p[i]] = i;
     // return matrices
     return { 
       L: l, 
       U: u, 
-      p: p, 
+      p: pv, 
       toString: function () {
         return 'L: ' + this.L.toString() + '\nU: ' + this.U.toString() + '\nP: ' + this.p;
       }
@@ -369,7 +373,7 @@ function factory (type, config, load, typed) {
         ptr: uptr,
         size: usize
       }),
-      p: pv_oc,
+      p: pv_co,
       toString: function () {
         return 'L: ' + this.L.toString() + '\nU: ' + this.U.toString() + '\nP: ' + this.p;
       }

diff --git a/lib/function/algebra/sparse/cs_ipvec.js b/lib/function/algebra/sparse/cs_ipvec.js
@@ -13,7 +13,7 @@ function factory () {
   var cs_ipvec = function (p, b, n) {
     // vars 
     var k;
-    var n = p.length;
+    var n = b.length;
     var x = [];
     // check permutation vector was provided, p = null denotes identity
     if (p) {

diff --git a/lib/type/matrix/FibonacciHeap.js b/lib/type/matrix/FibonacciHeap.js
@@ -147,7 +147,7 @@ function factory (type, config, load, typed) {
    */
   FibonacciHeap.prototype.remove = function (node) {
     // decrease key value
-    this._minimum = _decreaseKey(this._minimum, node, null);
+    this._minimum = _decreaseKey(this._minimum, node, -1);
     // remove the smallest
     this.extractMinimum();
   };

diff --git a/test/function/algebra/decomposition/lup.test.js b/test/function/algebra/decomposition/lup.test.js
@@ -148,7 +148,7 @@ describe('lup', function () {
         [0, 0, 0, 4]
       ]);
     // P
-    assert.deepEqual(r.p, [2, 1, 3, 0]);
+    assert.deepEqual(r.p, [3, 1, 0, 2]);
     // verify
     approx.deepEqual(math.multiply(_p(r.p), m).valueOf(), math.multiply(r.L, r.U).valueOf());
   });
@@ -304,7 +304,7 @@ describe('lup', function () {
         [0, 0, 0, 4]
       ]);
     // P
-    assert.deepEqual(r.p, [2, 1, 3, 0]);
+    assert.deepEqual(r.p, [3, 1, 0, 2]);
     // verify
     approx.deepEqual(math.multiply(_p(r.p), m).valueOf(), math.multiply(r.L, r.U).valueOf());
   });
@@ -375,21 +375,14 @@ describe('lup', function () {
    * Creates a Matrix out of a row permutation vector
    */
   function _p(p) {
+    // identity matrix
+    var identity = math.eye(p.length);
     // array
     var data = [];
     // loop rows
     for (var i = 0, l = p.length; i < l; i++) {
-      // row
-      var r = p[i];
-      // init data row
-      data[i] = [];
-      // loop columns
-      for (var j = 0; j < l; j++) {
-        if (r === j)
-          data[i][j] = 1;
-        else
-          data[i][j] = 0;
-      }      
+      // swap row
+      data[p[i]] = identity._data[i];
     }
     return data;
   }

diff --git a/test/function/algebra/solver/lusolve.test.js b/test/function/algebra/solver/lusolve.test.js
@@ -220,20 +220,38 @@ describe('lusolve', function () {
     approx.deepEqual(x, [[-5/3], [7/3], [-1]]);
   });
 
-  it('should solve linear system 3 x 3, permutations, matrix', function () {
+  it('should solve linear system 4 x 4, permutations, matrix - Issue 437', function () {
     var m = math.matrix(
       [
-        [1, 2, -1],
-        [2, 1, 1],
-        [1, 2, 1]
+        [ -1, 1, -1, 1],
+        [ 0, 0, 0, 1],
+        [ 1, 1, 1, 1],
+        [ 8, 4, 2, 1]
       ]);
-    var b = [4, -2, 2];
+
+    var b = [0.1, 0.2, 0.15, 0.1];
 
     var x = math.lusolve(m, b);
 
-    approx.deepEqual(x, math.matrix([[-5/3], [7/3], [-1]]));
+    approx.deepEqual(x, math.matrix([[0.025], [-0.075], [0], [0.2]]));
   });
 
+  it('should solve linear system 4 x 4, permutations, sparse - Issue 437', function () {
+    var m = math.sparse(
+      [
+        [ -1, 1, -1, 1],
+        [ 0, 0, 0, 1],
+        [ 1, 1, 1, 1],
+        [ 8, 4, 2, 1]
+      ]);
+
+    var b = [0.1, 0.2, 0.15, 0.1];
+
+    var x = math.lusolve(m, b);
+
+    approx.deepEqual(x, math.matrix([[0.025], [-0.075], [0], [0.2]]));
+  });
+
   it('should solve linear system 3 x 3, permutations, sparse matrix', function () {
     var m = math.matrix(
       [