def METHOD_NAME(self, input_file):
    """
    Read input files for forward modeling GRAV data with integral form
    INPUT:
    input_file: File name containing the forward parameter
    OUTPUT:
    mshfile
    obsfile
    topofile
    start model
    ref model
    active cells model
    weightfile
    chi_target
    as, ax ,ay, az
    upper, lower bounds
    lp, lqx, lqy, lqz
    eps_p, eps_q
    # All files should be in the working directory,
    # otherwise the path must be specified.
    """
    fid = open(self.basePath + input_file, "r")
    # Line 1: Mesh
    line = fid.readline()
    l_input = re.split(r"[!\s]", line)
    mshfile = l_input[1].rstrip()
    # Line 2: Observation file
    line = fid.readline()
    l_input = re.split(r"[!\s]", line)
    obsfile = l_input[1].rstrip()
    # Line 3: Topo, active-dyn, active-static
    topofile = None
    staticInput = None
    line = fid.readline()
    l_input = re.split(r"[!\s]", line)
    if l_input[0] == "TOPO":
        topofile = l_input[1].rstrip()
    elif l_input[0] == "VALUE":
        staticInput = float(l_input[1])
    elif l_input[0] == "FILE":
        staticInput = l_input[1].rstrip()
    # Line 4: Starting model
    line = fid.readline()
    l_input = re.split(r"[!\s]", line)
    if l_input[0] == "VALUE":
        mstart = float(l_input[1])
    elif l_input[0] == "FILE":
        mstart = l_input[1].rstrip()
    # Line 5: Reference model
    line = fid.readline()
    l_input = re.split(r"[!\s]", line)
    if l_input[0] == "VALUE":
        mref = float(l_input[1])
    elif l_input[0] == "FILE":
        mref = l_input[1].rstrip()
    # Line 6: Cell weights
    line = fid.readline()
    l_input = re.split(r"[!\s]", line)
    if l_input[0] == "DEFAULT":
        wgtfile = None
    elif l_input[0] == "FILE":
        wgtfile = l_input[1].rstrip()
    # Line 7: Target chi-factor
    line = fid.readline()
    l_input = re.split(r"[!\s]", line)
    if l_input[0] == "DEFAULT":
        chi = 1.0
    elif l_input[0] == "VALUE":
        chi = float(l_input[1])
    # Line 8: Alpha values
    line = fid.readline()
    l_input = re.split(r"[!\s]", line)
    if l_input[0] == "VALUE":
        val = np.array(l_input[1:5])
        alphas = val.astype(float)
    elif l_input[0] == "DEFAULT":
        alphas = np.ones(4)
    # Line 9: Bounds
    line = fid.readline()
    l_input = re.split(r"[!\s]", line)
    if l_input[0] == "VALUE":
        val = np.array(l_input[1:3])
        bounds = val.astype(float)
    elif l_input[0] == "FILE":
        bounds = l_input[1].rstrip()
    else:
        bounds = [-np.inf, np.inf]
    # Line 10: Norms
    line = fid.readline()
    l_input = re.split(r"[!\s]", line)
    if l_input[0] == "VALUE":
        val = np.array(l_input[1:6])
        lpnorms = val.astype(float)
    elif l_input[0] == "FILE":
        lpnorms = l_input[1].rstrip()
    # Line 11: Treshold values
    line = fid.readline()
    l_input = re.split(r"[!\s]", line)
    if l_input[0] == "VALUE":
        val = np.array(l_input[1:3])
        eps = val.astype(float)
    elif l_input[0] == "DEFAULT":
        eps = None
    self.mshfile = mshfile
    self.obsfile = obsfile
    self.topofile = topofile
    self.mstart = mstart
    self._mrefInput = mref
    self._staticInput = staticInput
    self.wgtfile = wgtfile
    self.chi = chi
    self.alphas = alphas
    self.bounds = bounds
    self.lpnorms = lpnorms
    self.eps = eps