diff --git a/pyqmri/solver.py b/pyqmri/solver.py
index 07c0feb..081e07c 100644
--- a/pyqmri/solver.py
+++ b/pyqmri/solver.py
@@ -165,8 +165,8 @@ def run(self, data, iters=30, lambd=1e-5, tol=1e-8, guess=None,
         for i in range(iters):
             self._operator_lhs(Ax, p)
             Ax = Ax + lambd*p
-            alpha = (clarray.vdot(res, res) /
-                     (clarray.vdot(p, Ax))).real.get()
+            alpha = float((clarray.vdot(res, res) /
+                     (clarray.vdot(p, Ax))).real.get())
             x = (x + alpha*p)
             res_new = res - alpha*Ax
             delta = np.linalg.norm(res_new.get())**2 /\
@@ -177,8 +177,8 @@ def run(self, data, iters=30, lambd=1e-5, tol=1e-8, guess=None,
                 del Ax, \
                     b, res, p, data, res_new
                 return np.squeeze(x.get())
-            beta = (clarray.vdot(res_new, res_new) /
-                    clarray.vdot(res, res)).real.get()
+            beta = float((clarray.vdot(res_new, res_new) /
+                    clarray.vdot(res, res)).real.get())
             p = res_new + beta * p
             (res, res_new) = (res_new, res)
         del Ax, b, res, p, data, res_new