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--- /dev/null
+++ b/scripts/polynomial/poly.m
@@ -0,0 +1,33 @@
+function y = poly (x)
+  #
+  # If A is a square n-by-n matrix, poly (A) is the row vector of 
+  # the coefficients of det (z * eye(n) - A), the characteristic
+  # polynomial of A.
+  # If x is a vector, poly (x) is a vector of coefficients of the
+  # polynomial whose roots are the elements of x.
+
+  # Written by KH (Kurt.Hornik@neuro.tuwien.ac.at) on Dec 24, 1993 
+  # Copyright Dept of Probability Theory and Statistics TU Wien
+
+  m = min (size (x));
+  n = max (size (x));
+  if (m == 0)
+    y = 1;
+  elseif (m == 1)
+    v = x;
+  elseif (m == n)
+    v = eig (x);
+  else
+    error ("usage:  poly(x), where x is a vector or a square matrix");
+  endif
+  
+  y = [1, zeros (1, n)];
+  for j = 1:n;
+    y(2:(j+1)) = y(2:(j+1)) - v(j) .* y(1:j);
+  endfor
+  
+  if (all (all (imag (x) == 0)))
+    y = real (y);
+  endif
+  
+endfunction