diff --git a/code/code_gen/code_gen.py b/code/code_gen/code_gen.py
index 86dc1be..78ba446 100644
--- a/code/code_gen/code_gen.py
+++ b/code/code_gen/code_gen.py
@@ -65,6 +65,9 @@ calc_grammar = """
     %import common.NUMBER
     %import common.WS
 
+    COMMENT: /#.*/
+
+    %ignore COMMENT
     %ignore WS
 """
 
diff --git a/code/code_gen/terms.input b/code/code_gen/terms.input
index ee4555b..48dffff 100644
--- a/code/code_gen/terms.input
+++ b/code/code_gen/terms.input
@@ -1,72 +1,15 @@
 [u, v, w, y]
 
+# field_name (arg_name=arg (, pair)* ) = expression
+
 c = 1.0 - y
-wrate = rxn_rate(c)
 
-mask1 = $threshold_min_max(c, 0.05, 0.15)
-mask2 = $threshold_min_max(c, 0.15, 0.25)
-mask3 = $threshold_min_max(c, 0.25, 0.35)
-mask4 = $threshold_min_max(c, 0.35, 0.45)
-mask5 = $threshold_min_max(c, 0.45, 0.55)
-mask6 = $threshold_min_max(c, 0.55, 0.65)
-mask7 = $threshold_min_max(c, 0.65, 0.75)
-mask8 = $threshold_min_max(c, 0.75, 0.85)
-mask9 = $threshold_min_max(c, 0.85, 0.95)
+fsd = sqrt (sqr(ddx(c)) + sqr(ddy(c)) + sqr(ddz(c)))
 
-fsd_orig = sqrt (sqr(ddx(c)) + sqr(ddy(c)) + sqr(ddz(c)))
-
-fsd = fsd_orig * mask
-
-fsd1 = fsd_orig * mask1
-fsd2 = fsd_orig * mask2
-fsd3 = fsd_orig * mask3
-fsd4 = fsd_orig * mask4
-fsd5 = fsd_orig * mask5
-fsd6 = fsd_orig * mask6
-fsd7 = fsd_orig * mask7
-fsd8 = fsd_orig * mask8
-fsd9 = fsd_orig * mask9
-
-sd = ((d2dx(c) + d2dy(c) + d2dz(c)) * $rod + wrate) / fsd_orig
-
-nx = - ddx(c) / fsd_orig
-ny = - ddy(c) / fsd_orig
-nz = - ddz(c) / fsd_orig
-
-vn = u * nx + v * ny + w * nz
+nx = - ddx(c) / fsd
+ny = - ddy(c) / fsd
+nz = - ddz(c) / fsd
 
 divn = ddx(nx) + ddy(ny) + ddz(nz)
 
-absk = abs(divn)
-
-lapc = d2dx(c) + d2dy(c) + d2dz(c)
-
-t1 = (vn + sd) * nx
-
-t2 = t1' * nx'
-
-t3 = t1' * divn'
-
-t4 = t1' * absk'
-
-t5 = sqr(t1')
-
-t6 = sqr(nx')
-
-t7 = sqr(divn')
-
-t8 = sqr(absk')
-
-avg { c, u, v, w, fsd1, fsd2, fsd3, fsd4, fsd5, fsd6, fsd7, fsd8, fsd9, lapc, ddx_c, ddy_c, ddz_c, d2dx_c, d2dy_c, d2dz_c }
-
-avg fsd1 { nx, ny, nz, t1, t2, t3, t4, t5, t6, t7, t8, absk, divn, sd }
-avg fsd2 { nx, ny, nz, t1, t2, t3, t4, t5, t6, t7, t8, absk, divn, sd }
-avg fsd3 { nx, ny, nz, t1, t2, t3, t4, t5, t6, t7, t8, absk, divn, sd }
-avg fsd4 { nx, ny, nz, t1, t2, t3, t4, t5, t6, t7, t8, absk, divn, sd }
-avg fsd5 { nx, ny, nz, t1, t2, t3, t4, t5, t6, t7, t8, absk, divn, sd }
-avg fsd6 { nx, ny, nz, t1, t2, t3, t4, t5, t6, t7, t8, absk, divn, sd }
-avg fsd7 { nx, ny, nz, t1, t2, t3, t4, t5, t6, t7, t8, absk, divn, sd }
-avg fsd8 { nx, ny, nz, t1, t2, t3, t4, t5, t6, t7, t8, absk, divn, sd }
-avg fsd9 { nx, ny, nz, t1, t2, t3, t4, t5, t6, t7, t8, absk, divn, sd }
-
-
+avg { c, fsd, divn }