I present a pseudounitary pull adjoint as an alternative to the exact adjoint in least squares stacking. Pull adjoints are a good choice for wave equation based operators because they more closely approximate an operator in a continuum. An operator pair which includes pull adjoints produces faster convergence in a least squares stacking example than an exactly adjoint operator pair, despite failing the dot product test. This is because they more closely approximate the continuous wave equation than an exactly adjoint operator pair.

11/12/1997