Reduced row echelon form: Difference between revisions

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@@ Line 700: / Line 700: @@
 =={{header|D}}==
-<lang d>import std.stdio, std.algorithm;
+<lang d>import std.stdio, std.algorithm, std.array, std.conv;
-pure nothrow bool isRectangular(T)(in T[][] M) {
+void toReducedRowEchelonForm(T)(T[][] M) pure {
-    foreach (row; M)
+    const nrows = M.length;
-        if (row.length != M[0].length)
+    if (!nrows) return;
-            return false;
+    const ncols = M[0].length;
-    return true;
+    int lead;
+    foreach (r; 0 .. nrows) {
-}
+        if (ncols <= lead) return;
-pure void toReducedRowEchelonForm(T)(T[][] M)
-in {
-    assert(isRectangular(M));
-}
-body {
-    if (!M.length)
-        return;
-    immutable int rowCount = M.length;
-    immutable int columnCount = M[0].length;
-    int lead = 0;
-    foreach (r; 0 .. rowCount) {
-        if (columnCount <= lead)
-            return;
         int i = r;
-        while (M[i][lead] == 0) {
+        while (M[i][lead] == 0)
-            i++;
+            if (nrows == ++i) {
-            if (rowCount == i) {
                 i = r;
-                lead++;
+                if (ncols == ++lead) return;
-                if (columnCount == lead)
-                    return;
             }
-        }
         swap(M[i], M[r]);
         M[r][] /= M[r][lead];
-        foreach (j; 0 .. rowCount)
+        foreach (j; 0 .. nrows)
             if (j != r)
                 M[j][] -= M[r][] * M[j][lead];
@@ Line 742: / Line 725: @@
 void main() {
-    auto mtx = [[ 1, 2, -1,  -4],
+    auto A = [[ 1, 2, -1,  -4],
-                [ 2, 3, -1, -11],
+              [ 2, 3, -1, -11],
-                [-2, 0, -3,  22]];
+              [-2, 0, -3,  22]];
-    toReducedRowEchelonForm(mtx);
+    toReducedRowEchelonForm(A);
+    writeln("[", array(map!text(A)).join("\n "), "]");
-    foreach (row; mtx)
-        writeln(row);
 }</lang>
 Output:
-<pre>[1, 0, 0, -8]
+<pre>[[1, 0, 0, -8]
-[0, 1, 0, 1]
+ [0, 1, 0, 1]
-[0, 0, 1, -2]</pre>
+ [0, 0, 1, -2]]</pre>
 =={{header|Euphoria}}==