Kernel tested

examples/exploratory_scripts/009_test_qgaussian/001_with_def_kernels.py

@@ -0,0 +1,58 @@
+import time
+
+import numpy as np
+
+import xobjects as xo
+from xfields.contexts import add_default_kernels
+
+from pysixtrack.be_beamfields.gaussian_fields import get_Ex_Ey_Gx_Gy_gauss
+from pysixtrack.mathlibs import MathlibDefault
+
+ctx = xo.ContextCpu()
+ctx = xo.ContextCpu(omp_num_threads=4)
+#ctx = xo.ContextCupy()
+#ctx = xo.ContextPyopencl()
+
+print(ctx)
+
+
+kernel_descriptions = {'q_gaussian_profile':{
+    'args':(
+    (('scalar', np.int32  ), 'n'),
+    (('array',  np.float64), 'z'),
+    (('scalar', np.float64), 'z0'),
+    (('scalar', np.float64), 'z_min'),
+    (('scalar', np.float64), 'z_max'),
+    (('scalar', np.float64), 'beta'),
+    (('scalar', np.float64), 'q'),
+    (('scalar', np.float64), 'q_tol'),
+    (('scalar', np.float64), 'factor'),
+    (('array',  np.float64), 'res'),
+        ),
+    'num_threads_from_arg': 'n'
+    },}
+
+ctx.add_kernels(src_files=['../../../xfields/src/qgaussian.h'],
+                kernel_descriptions=kernel_descriptions)
+
+import matplotlib.pyplot as plt
+plt.close('all')
+plt.figure(1)
+for qq in [0.95, 1., 1.05]:
+    z = np.linspace(-2., 2., 1000)
+    res = 0*z
+    ctx.kernels.q_gaussian_profile(
+            n=len(z),
+            z=z,
+            z0=0.5,
+            z_min=-0.8,
+            z_max=1.9,
+            beta=1./2./0.5**2,
+            q=qq,
+            q_tol=1e-10,
+            factor=1,
+            res=res)
+    plt.plot(z, res, label=f'q={qq}')
+
+plt.legend(loc='best')
+plt.show()

xfields/src/qgaussian.h

@@ -1,17 +1,20 @@
+#ifndef QGAUSSIAN 
+#define QGAUSSIAN 
+
 #include <math.h> //only_for_context none
 
 
 /*gpukern*/
 void q_gaussian_profile(
-		    const int n,
+		    const int     n,
       /*gpuglmem*/  const double* z,
-		    const double z0,
-		    const double z_min,
-		    const double z_max,
-		    const double beta, 
-		    const double q, 
-		    const double q_tol,
-		    const double factor,
+		    const double  z0,
+		    const double  z_min,
+		    const double  z_max,
+		    const double  beta, 
+		    const double  q, 
+		    const double  q_tol,
+		    const double  factor,
       /*gpuglmem*/        double* res){
 
     if (fabs(q-1.) < q_tol){
@@ -35,7 +38,8 @@ void q_gaussian_profile(
 	    if (zi<z_max && zi>z_min){
 		double zi_m_z0 = zi - z0;
     	    	double q_exp_arg =  -(beta*zi_m_z0*zi_m_z0 );
-    	    	double q_exp_res = pow(q_exp_arg, exponent );
+    	    	double q_exp_res = pow(
+			 (1.+(1.-q)*q_exp_arg), exponent );
     	    	res[ii] = factor*q_exp_res;
 	    }
 	    else{
@@ -44,3 +48,5 @@ void q_gaussian_profile(
     	}//end_vectorize
     }
 }	
+
+#endif