Replace M_PI=np.arccos(-1) with M_PI=np.pi (tardis-sn#2870)

* Replace np.arccos(-1) with np.pi

* added name and mail to .mailmap file

* Changed M_PI to PI

.mailmap

@@ -286,3 +286,5 @@ Israel Roldan <israel.alberto.rv@gmail.com> AirvZxf <israel.alberto.rv@gmail.com
 Israel Roldan <israel.alberto.rv@gmail.com> airv_zxf <israel.alberto.rv@gmail.com>
 
 Michael Zingale <michael.zingale@stonybrook.edu>
+
+Akash Kaushik <akash265457k@gmail.com>

tardis/spectrum/formal_integral.py

@@ -24,7 +24,7 @@
 )
 
 C_INV = 3.33564e-11
-M_PI = np.arccos(-1)
+PI = np.pi
 KB_CGS = 1.3806488e-16
 H_CGS = 6.62606957e-27
 
@@ -197,7 +197,7 @@ def numba_formal_integral(
                 pJred_lu += direction
                 pJblue_lu += direction
             I_nu[p_idx] *= p
-        L[nu_idx] = 8 * M_PI * M_PI * trapezoid_integration(I_nu, R_max / N)
+        L[nu_idx] = 8 * PI * PI * trapezoid_integration(I_nu, R_max / N)
 
     return L, I_nu_p
 
@@ -640,7 +640,7 @@ def formal_integral(self, nu, N):
         I_nu = self.transport.I_nu_p * ps
         L_test = np.array(
             [
-                8 * M_PI * M_PI * trapezoid_integration((I_nu)[i, :], R_max / N)
+                8 * PI * PI * trapezoid_integration((I_nu)[i, :], R_max / N)
                 for i in range(nu.shape[0])
             ]
         )

tardis/spectrum/formal_integral_cuda.py

@@ -6,7 +6,7 @@
 from tardis.transport.montecarlo.configuration.constants import SIGMA_THOMSON
 
 C_INV = 3.33564e-11
-M_PI = np.arccos(-1)
+PI = np.pi
 KB_CGS = 1.3806488e-16
 H_CGS = 6.62606957e-27
 
@@ -28,7 +28,7 @@ def cuda_vector_integrator(L, I_nu, N, R_max):
     """
     nu_idx = cuda.grid(1)
     L[nu_idx] = (
-        8 * M_PI * M_PI * trapezoid_integration_cuda(I_nu[nu_idx], R_max / N)
+        8 * PI * PI * trapezoid_integration_cuda(I_nu[nu_idx], R_max / N)
     )