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authorAdrian Kummerlaender2019-11-09 20:21:27 +0100
committerAdrian Kummerlaender2019-11-09 20:40:33 +0100
commit27ce855378a80dff680c2989800af1f4e69975fe (patch)
tree887c58dfaf209721bd3e8240d52a042f54028d24 /boltzgen/kernel
parent286e243a171c8bcdfc91b5b6dcdd937ac95b0b7b (diff)
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Implement basic version of the SSS pattern for C++ target
An interesting extension of the AA pattern. The main advantage of this is that updating pointers in a control structure is much more elegant than duplicating all function implementations as is required by the normal AA pattern. For more details see [1]. Only works for the SOA layout. On a pure memory access level this pattern is equivalent to the AA pattern. The difference is how the memory locations are calculated (by pointer swap & shift or by different indexing functions for odd and even time steps). [1]: "An auto-vectorization friendly parallel lattice Boltzmann streaming scheme for direct addressing" by Mohrhard et al. (2019)
Diffstat (limited to 'boltzgen/kernel')
-rw-r--r--boltzgen/kernel/template/pattern/SSS.cpp.mako55
-rw-r--r--boltzgen/kernel/template/update_sss_control_structure.cpp.mako15
2 files changed, 70 insertions, 0 deletions
diff --git a/boltzgen/kernel/template/pattern/SSS.cpp.mako b/boltzgen/kernel/template/pattern/SSS.cpp.mako
new file mode 100644
index 0000000..a60b03a
--- /dev/null
+++ b/boltzgen/kernel/template/pattern/SSS.cpp.mako
@@ -0,0 +1,55 @@
+<%def name="operator(name, params = None)">
+<%
+if layout.__class__.__name__ != 'SOA':
+ raise Exception('SSS pattern only works for the AOS memory layout')
+%>
+void ${name}(
+ ${float_type}** f
+ , std::size_t gid
+% if params is not None:
+% for param_type, param_name in params:
+ , ${param_type} ${param_name}
+% endfor
+% endif
+) {
+% for i, c_i in enumerate(descriptor.c):
+ ${float_type}* preshifted_f_${i} = f[${i}] + ${layout.cell_preshift('gid')};
+% endfor
+
+% for i, c_i in enumerate(descriptor.c):
+ const ${float_type} f_curr_${i} = *preshifted_f_${i};
+% endfor
+
+ ${caller.body()}
+
+% for i, c_i in enumerate(descriptor.c):
+ *preshifted_f_${i} = f_next_${descriptor.c.index(-c_i)};
+% endfor
+}
+</%def>
+
+<%def name="functor(name, params = None)">
+<%
+if layout.__class__.__name__ != 'SOA':
+ raise Exception('SSS pattern only works for the AOS memory layout')
+%>
+void ${name}(
+ ${float_type}** f
+ , std::size_t gid
+% if params is not None:
+% for param_type, param_name in params:
+ , ${param_type} ${param_name}
+% endfor
+% endif
+) {
+% for i, c_i in enumerate(descriptor.c):
+ const ${float_type}* preshifted_f_${i} = f[${i}] + ${layout.cell_preshift('gid')};
+% endfor
+
+% for i, c_i in enumerate(descriptor.c):
+ const ${float_type} f_curr_${i} = *preshifted_f_${descriptor.c.index(-c_i)};
+% endfor
+
+ ${caller.body()}
+}
+</%def>
diff --git a/boltzgen/kernel/template/update_sss_control_structure.cpp.mako b/boltzgen/kernel/template/update_sss_control_structure.cpp.mako
new file mode 100644
index 0000000..9197022
--- /dev/null
+++ b/boltzgen/kernel/template/update_sss_control_structure.cpp.mako
@@ -0,0 +1,15 @@
+<%
+if streaming != 'SSS':
+ raise Exception('"update_sss_control_structure" function only makes sense for the SSS pattern')
+%>
+void update_sss_control_structure(${float_type}** f) {
+% for i, c_i in enumerate(descriptor.c):
+ ${float_type}* f_old_${i} = f[${i}];
+% endfor
+% for i, c_i in enumerate(descriptor.c):
+ f[${i}] = f_old_${descriptor.c.index(-c_i)};
+% endfor
+% for i, c_i in enumerate(descriptor.c):
+ f[${i}] += ${layout.neighbor_offset(-c_i)};
+% endfor
+}