- expressions can now be read from streams; the input expression can contain

[ginac.git] / ginac / matrix.cpp

diff --git a/ginac/matrix.cpp b/ginac/matrix.cpp
index fab7b5fde949e1a68f02623a04fe6d6636cb0140..f219f27de0c3dcb1432bcc7d944b4ef8bcd63dcc 100644 (file)
--- a/ginac/matrix.cpp
+++ b/ginac/matrix.cpp
@@ -26,9 +26,10 @@
 
 #include "matrix.h"
 #include "archive.h"
+#include "numeric.h"
+#include "lst.h"
 #include "utils.h"
 #include "debugmsg.h"
-#include "numeric.h"
 
 #ifndef NO_NAMESPACE_GINAC
 namespace GiNaC {
@@ -1218,6 +1219,29 @@ int matrix::pivot(unsigned ro, bool symbolic)
     return 0;
 }
 
+/** Convert list of lists to matrix. */
+ex lst_to_matrix(const ex &l)
+{
+       if (!is_ex_of_type(l, lst))
+               throw(std::invalid_argument("argument to lst_to_matrix() must be a lst"));
+
+       // Find number of rows and columns
+       unsigned rows = l.nops(), cols = 0, i, j;
+       for (i=0; i<rows; i++)
+               if (l.op(i).nops() > cols)
+                       cols = l.op(i).nops();
+
+       // Allocate and fill matrix
+       matrix &m = *new matrix(rows, cols);
+       for (i=0; i<rows; i++)
+               for (j=0; j<cols; j++)
+                       if (l.op(i).nops() > j)
+                               m.set(i, j, l.op(i).op(j));
+                       else
+                               m.set(i, j, ex(0));
+       return m;
+}
+
 //////////
 // global constants
 //////////