Provide better error messages in a few situations.

MEMO

@@ -58,6 +58,8 @@ Things to consider
 
 TODO
 ^^^^
+- assert dependencies <= parent_inames in loopy/__init__.py
+  ???
 
 - FIXME: Deal with insns losing a seq iname dep in a CSE realization
 

loopy/__init__.py

@@ -15,11 +15,6 @@ import numpy as np
 
 
 
-# TODO list moved to MEMO in root
-
-
-
-
 class LoopyAdvisory(UserWarning):
     pass
 
@@ -284,7 +279,7 @@ def realize_cse(kernel, cse_tag, dtype, duplicate_inames=[], parallel_inames=Non
 
             # the iname is *not* a dependency of the fetch expression
             if iname in duplicate_inames:
-                raise RuntimeError("duplicating an iname ('%s')"
+                raise RuntimeError("duplicating an iname ('%s') "
                         "that the CSE ('%s') does not depend on "
                         "does not make sense" % (iname, expr.child))
 

loopy/kernel.py

@@ -625,8 +625,9 @@ class LoopKernel(Record):
             all_inames_by_insns |= insn.all_inames()
 
         if all_inames_by_insns != self.all_inames():
-            raise RuntimeError("inames collected from instructions "
-                    "do not match domain inames")
+            raise RuntimeError("inames collected from instructions (%s) "
+                    "do not match domain inames (%s)"
+                    % (", ".join(all_inames_by_insns), ", ".join(self.all_inames())))
 
         global_sizes = {}
         local_sizes = {}
@@ -676,8 +677,8 @@ class LoopKernel(Record):
                 while cur_axis > len(size_list):
                     from loopy import LoopyAdvisory
                     from warnings import warn
-                    warn("%s axis %d unassigned--assuming length 1" % len(size_list),
-                            LoopyAdvisory)
+                    warn("%s axis %d unassigned--assuming length 1" % (
+                        which, len(size_list)), LoopyAdvisory)
                     size_list.append(1)
 
                 size_list.append(size_dict[cur_axis])

loopy/symbolic.py

@@ -336,12 +336,15 @@ class LoopyCCodeMapper(CCodeMapper):
                                 ary_strides, index_expr))), enclosing_prec)
 
 
-        if expr.aggregate.name in self.kernel.temporary_variables:
+        elif expr.aggregate.name in self.kernel.temporary_variables:
             temp_var = self.kernel.temporary_variables[expr.aggregate.name]
 
             return (temp_var.name + "".join("[%s]" % self.rec(idx, PREC_NONE)
                 for idx in expr.index))
 
+        else:
+            raise RuntimeError("nothing known about variable '%s'" % expr.aggregate.name)
+
     def map_floor_div(self, expr, prec):
         if isinstance(expr.denominator, int) and expr.denominator > 0:
             return ("int_floor_div_pos_b(%s, %s)"