LU decomposition: Difference between revisions

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@@ Line 1,233: / Line 1,233: @@
 , 1, 0,
     }))
+    fmt.Println()
     showLU(mat64.NewDense(4, 4, []float64{
 , 9, 24, 2,
@@ Line 1,241: / Line 1,242: @@
 }
-func showLU(m *mat64.Dense) {
+func showLU(a *mat64.Dense) {
-    fmt.Printf("m:\n%v\n", M{m})
+    fmt.Printf("a: %v\n\n", mat64.Formatted(a, mat64.Prefix("   ")))
-    f := mat64.LU(m)
+    var lu mat64.LU
+    lu.Factorize(a)
-    fmt.Printf("l:\n%.5f\n", M{f.L()})
+    var l, u mat64.TriDense
-    fmt.Printf("u:\n%.5f\n", M{f.U()})
-    fmt.Println("p:", f.Pivot)
+    l.LFrom(&lu)
+    u.UFrom(&lu)
-}
+    fmt.Printf("l: %.5f\n\n", mat64.Formatted(&l, mat64.Prefix("   ")))
+    fmt.Printf("u: %.5f\n\n", mat64.Formatted(&u, mat64.Prefix("   ")))
-type M struct{ mat64.Matrix }
+    fmt.Println("p:", lu.Pivot(nil))
+}</lang>
-func (m M) Format(f fmt.State, c rune) { mat64.Format(m, 0, 0, f, c) }</lang>
 {{out}}
-Pivot format is a little different here.
+Pivot format is a little different here.  (But library solutions don't really meet task requirements anyway.)
 <pre>
+a: ⎡1  3  5⎤
-m:
+   ⎢2  4  7⎥
-⎡1  3  5⎤
+   ⎣1  1  0⎦
-⎢2  4  7⎥
-⎣1  1  0⎦
+l: ⎡ 1.00000   0.00000   0.00000⎤
-l:
-⎡ 1.00000   0.00000   0.00000⎤
+   ⎢ 0.50000   1.00000   0.00000⎥
-⎢ 0.50000   1.00000   0.00000⎥
+   ⎣ 0.50000  -1.00000   1.00000⎦
-⎣ 0.50000  -1.00000   1.00000⎦
+u: ⎡ 2.00000   4.00000   7.00000⎤
-u:
-⎡ 2.00000   4.00000   7.00000⎤
+   ⎢ 0.00000   1.00000   1.50000⎥
-⎢ 0.00000   1.00000   1.50000⎥
+   ⎣ 0.00000   0.00000  -2.00000⎦
-⎣ 0.00000   0.00000  -2.00000⎦
 p: [1 0 2]
-m:
-⎡11   9  24   2⎤
+a: ⎡11   9  24   2⎤
-⎢ 1   5   2   6⎥
+   ⎢ 1   5   2   6⎥
-⎢ 3  17  18   1⎥
+   ⎢ 3  17  18   1⎥
-⎣ 2   5   7   1⎦
+   ⎣ 2   5   7   1⎦
-l:
-⎡1.00000  0.00000  0.00000  0.00000⎤
+l: ⎡1.00000  0.00000  0.00000  0.00000⎤
-⎢0.27273  1.00000  0.00000  0.00000⎥
+   ⎢0.27273  1.00000  0.00000  0.00000⎥
-⎢0.09091  0.28750  1.00000  0.00000⎥
+   ⎢0.09091  0.28750  1.00000  0.00000⎥
-⎣0.18182  0.23125  0.00360  1.00000⎦
+   ⎣0.18182  0.23125  0.00360  1.00000⎦
-u:
-⎡11.00000   9.00000  24.00000   2.00000⎤
+u: ⎡11.00000   9.00000  24.00000   2.00000⎤
-⎢ 0.00000  14.54545  11.45455   0.45455⎥
+   ⎢ 0.00000  14.54545  11.45455   0.45455⎥
-⎢ 0.00000   0.00000  -3.47500   5.68750⎥
+   ⎢ 0.00000   0.00000  -3.47500   5.68750⎥
-⎣ 0.00000   0.00000   0.00000   0.51079⎦
+   ⎣ 0.00000   0.00000   0.00000   0.51079⎦
 p: [0 2 1 3]
 </pre>