function T=heat(efcns,wn,cn,k,x,t,dummy)
 
  $Id: heat.m,v 1.12 2003-01-05 15:32:33-06 brinkman Exp $
  (c) 2002, Peter Brinkmann (brinkman@math.uiuc.edu)
 
  heat: computes series solutions of the heat equation u_xx=ku_t
 
  Usage: T=heat('cosef', (0:3)', [.5;-1;-2;3.4], 1, 0:0.1:pi, 0:0.1:5)
 
  Parameters:
 	efcns: string containing the name of a function that computes
 		eigenfunctions, or an inline function
 	wn: a column vector of square roots of eigenvalues
 	cn: a column vector of coefficients in series expansion of initial
 		temperature distribution
 	k: thermal diffusivity
 	x: row vector of x-values
 	t: row vector of t-values
 	dummy: (optional) dummy parameter to make sure that heat.m takes as many
 		parameters as wave.m (just to make Matlab happy...)
 
  Return values:
 	T: rectangular grid of values of the solution u(x,t)