# coding: utf-8

# # Generating an OpenCL Kernel using Textual Templating

# A more advanced, but also less lightweight, alternative is the usage of a so-called templating engine, as it is being used to generate web pages.
# 
# This offers tremendous flexibility in generation, including the possibility for full flow control, allowing applications such as loop unrolling.
# 
# In the example below, we use a templating engine called 'Mako':

# In[1]:

from mako.template import Template


# In[2]:

tpl = Template(r"""
    __kernel void ${name}(${arguments})
    {
      int lid = get_local_id(0);
      int gsize = get_global_size(0);
      int work_group_start = get_local_size(0)*get_group_id(0);
      long i;

      for (i = work_group_start + lid; i < n; i += gsize)
      {
        %for i_unroll in range(n_unroll):
            ${operation};
            %if i_unroll + 1 < n_unroll:
                i += gsize;
            %endif
        %endfor
      }
    }
""", strict_undefined=True)


# In[3]:

print(tpl.render(
    name="scale",
    arguments="float *y, float a, float *x",
    operation="y[i] = a*x[i]",
    n_unroll=2,
))


# In[ ]: