Add automatic loop thread assignment.

- Number of threads is determined by BLIS_NUM_THREADS or OMP_NUM_THREADS, but can be overridden by BLIS_XX_NT as before.
- Threads are assigned to loops (ic, jc, ir, and jc) automatically by weighted partitioning and heuristics, both of which are tunable via bli_kernel.h.
- All level-3 BLAS covered.

frame/include/bli_kernel_macro_defs.h

@@ -1347,6 +1347,26 @@
 #endif
 
 
+// -- Define default threading parameters --------------------------------------
+
+
+#ifndef BLIS_DEFAULT_M_THREAD_RATIO
+#define BLIS_DEFAULT_M_THREAD_RATIO 2
+#endif
+
+#ifndef BLIS_DEFAULT_N_THREAD_RATIO
+#define BLIS_DEFAULT_N_THREAD_RATIO 1
+#endif
+
+#ifndef BLIS_DEFAULT_MR_THREAD_MAX
+#define BLIS_DEFAULT_MR_THREAD_MAX 1
+#endif
+
+#ifndef BLIS_DEFAULT_NR_THREAD_MAX
+#define BLIS_DEFAULT_NR_THREAD_MAX 3
+#endif
+
+
 // -- Kernel blocksize checks --------------------------------------------------
 
 // Verify that cache blocksizes are whole multiples of register blocksizes.