Made wronskian work with empty matrices

This is necessary to apply variation of parameters to first order odes, such as f(x).diff(x) - sin(x) The determinant (and thus the wronskian) of an empty matrix is defined to be 1.
asmeurer · Aug 18, 2009 · 1e49496 · 1e49496
1 parent 4c9f90a
commit 1e49496
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/sympy/matrices/matrices.py b/sympy/matrices/matrices.py
@@ -1632,6 +1632,8 @@ def wronskian(functions, var):
     for index in xrange(0, len(functions)):
         functions[index] = sympify(functions[index])
     n = len(functions)
+    if n == 0:
+        return 1
     W = Matrix(n, n, lambda i,j: functions[i].diff(var, j) )
     return W.det()