; plotting methods
(defmeth inverse-proto :plot-solution ()
  (if (send self :constrained-solution)
      (let* ((solution (/ 1 (send self :constrained-solution)))
	 (zmin (send self :zmin))
	 (zmax (send self :zmax))
	 (solplot (plot-lines (rseq zmin zmax (length solution)) 
			      solution))
	 (eps (send self :eps))
	 )
    (send solplot :title 
	  (format nil "singular value truncation level ~f" eps))
    (send solplot :variable-label 0 "depth (m)")
    (send solplot :variable-label 1 "P-wave velocity (km/s)")
    (send solplot :adjust-to-data)
    (send solplot :draw-string  (format nil "~f minimum sval used"
					eps) 0 0)
    (send solplot :location 50 100)
    )
  )
  )

(defmeth inverse-proto :plot-response ()
  (let* ((solution (send self :constrained-solution))
	 (zmin (send self :zmin))
	 (zmax (send self :zmax))
	 (jac (send self :jacobian))
	 (response (send self :response))
	 (rhs (send self :rhs))
	 (ttplot (plot-lines (rseq zmin zmax (length rhs)) rhs))
	 )
    (if response
    (send ttplot :add-lines (rseq zmin zmax (length response)) response)
    )
    (send ttplot :title "observed vs computed travel times")
    (send ttplot :variable-label 0 "receiver depth (m)")
    (send ttplot :variable-label 1 "travel time (ms)")
    (send ttplot :location 450 100)
    (send ttplot :adjust-to-data)

    )
  )

(defmeth inverse-proto :residual-histogram ()
  (let* ((obsdata (send self :rhs))
	  (compdata (send self :response))
	  (error (- obsdata compdata))
	  (histoplot (histogram error))
	  )
    (send histoplot :title "data residuals")
    (send histoplot :location 50 560)
    )
  )