add logic depth example

UsageExamples.ipynb

@@ -430,6 +430,122 @@
     "    print(c.kind, c.name)"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### Determining Logic Depth of Nodes"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 15,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "<Circuit 'b14' with 31715 nodes, 46891 lines, 91 ports>"
+      ]
+     },
+     "execution_count": 15,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "from kyupy import verilog\n",
+    "\n",
+    "b14 = verilog.parse('tests/b14.v.gz')\n",
+    "b14"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Calculate logic level (logic depth, distance from inputs or scan flip-flops) for each node in the circuit.\n",
+    "Inputs and flip-flops themselves are level 0, **cells** driven by just inputs and flip-flops are level 1, and so on.\n",
+    "**Fork** nodes have the same level as their driver, because they do not increase the logic depth."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 16,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Maximum logic depth: 112\n"
+     ]
+    }
+   ],
+   "source": [
+    "import numpy as np\n",
+    "\n",
+    "levels = np.zeros(len(b14.nodes), dtype='uint16')  # store level for each node.\n",
+    "\n",
+    "for cell in b14.topological_order():\n",
+    "    if 'DFF' in cell.kind or 'input' == cell.kind:\n",
+    "        levels[cell.index] = 0\n",
+    "    elif '__fork__' == cell.kind:\n",
+    "        levels[cell.index] = levels[cell.ins[0].driver.index]  # forks only have exactly one driver\n",
+    "    else:\n",
+    "        levels[cell.index] = max([levels[line.driver.index] for line in cell.ins]) + 1\n",
+    "        \n",
+    "print(f'Maximum logic depth: {np.max(levels)}')"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "List nodes with the highest depth and which nodes they are driving."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 17,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "depth: 112 node: __fork__     n2692  driving: SDFFARX1_RVT reg1_reg_29_  \n",
+      "depth: 112 node: NAND2X0_RVT  U465   driving: __fork__     n2692         \n",
+      "depth: 112 node: NAND2X0_RVT  U562   driving: __fork__     n2724         \n",
+      "depth: 112 node: __fork__     n2724  driving: SDFFARX1_RVT reg0_reg_29_  \n",
+      "depth: 112 node: __fork__     n2608  driving: SDFFARX1_RVT B_reg         \n",
+      "depth: 112 node: NAND2X0_RVT  U170   driving: __fork__     n2608         \n",
+      "depth: 111 node: NAND2X0_RVT  U5550  driving: __fork__     n2693         \n",
+      "depth: 111 node: __fork__     n2660  driving: SDFFARX1_RVT reg2_reg_29_  \n",
+      "depth: 111 node: AND2X2_RVT   U5560  driving: __fork__     n2660         \n",
+      "depth: 111 node: __fork__     n2725  driving: SDFFARX1_RVT reg0_reg_28_  \n",
+      "depth: 111 node: __fork__     n2693  driving: SDFFARX1_RVT reg1_reg_28_  \n",
+      "depth: 111 node: __fork__     n362   driving: NAND2X0_RVT  U170          \n",
+      "depth: 111 node: NAND2X0_RVT  U173   driving: __fork__     n362          \n",
+      "depth: 111 node: __fork__     n600   driving: NAND2X0_RVT  U562          \n",
+      "depth: 111 node: NAND2X0_RVT  U563   driving: __fork__     n600          \n",
+      "depth: 111 node: NAND2X0_RVT  U565   driving: __fork__     n2725         \n",
+      "depth: 111 node: NAND2X0_RVT  U466   driving: __fork__     n535          \n",
+      "depth: 111 node: __fork__     n535   driving: NAND2X0_RVT  U465          \n",
+      "depth: 110 node: __fork__     n4691  driving: AND2X2_RVT   U5560         \n",
+      "depth: 110 node: NAND2X0_RVT  U5736  driving: __fork__     n790          \n"
+     ]
+    }
+   ],
+   "source": [
+    "nodes_by_depth = np.argsort(levels)[::-1]\n",
+    "\n",
+    "for n_idx in nodes_by_depth[:20]:\n",
+    "    n = b14.nodes[n_idx]\n",
+    "    readers = ', '.join([f'{l.reader.kind:12s} {l.reader.name:14s}' for l in n.outs])\n",
+    "    print(f'depth: {levels[n_idx]} node: {n.kind:12s} {n.name:6s} driving: {readers}')"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -446,7 +562,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 15,
+   "execution_count": 18,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -469,7 +585,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 16,
+   "execution_count": 19,
    "metadata": {},
    "outputs": [
     {
@@ -478,7 +594,7 @@
        "<PackedVectors nvectors=1081, width=306, vdim=2>"
       ]
      },
-     "execution_count": 16,
+     "execution_count": 19,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -496,7 +612,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 17,
+   "execution_count": 20,
    "metadata": {},
    "outputs": [
     {
@@ -505,7 +621,7 @@
        "(306, 2, 136)"
       ]
      },
-     "execution_count": 17,
+     "execution_count": 20,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -523,7 +639,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 18,
+   "execution_count": 21,
    "metadata": {},
    "outputs": [
     {
@@ -532,7 +648,7 @@
        "'-0--------------------11011111011001100111010101011101----------------------------------00-10111011010110011101110010111010111011101100010000110101111111011010101001010101010101010101001010110101001010101010101010110100000111111111111111011010100100101010010010101101010101001010100111010001010010000011100'"
       ]
      },
-     "execution_count": 18,
+     "execution_count": 21,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -543,7 +659,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 19,
+   "execution_count": 22,
    "metadata": {},
    "outputs": [
     {
@@ -552,7 +668,7 @@
        "'--10000010010100010111--------------------------------0101010010101010110101001001010100--011111110011011111000111010101010111011101100010000110101111111011010101001010101010101010101001010110101001010101010101010110100000111111111111111011010100100101010010010101101010101001010101000111111111111111011101'"
       ]
      },
-     "execution_count": 19,
+     "execution_count": 22,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -570,7 +686,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 20,
+   "execution_count": 23,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -583,7 +699,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 21,
+   "execution_count": 24,
    "metadata": {},
    "outputs": [
     {
@@ -592,7 +708,7 @@
        "'--10000010010100010111--------------------------------0101010010101010110101001001010100--011111110011011111000111010101010111011101100010000110101111111011010101001010101010101010101001010110101001010101010101010110100000111111111111111011010100100101010010010101101010101001010101000111111111111111011101'"
       ]
      },
-     "execution_count": 21,
+     "execution_count": 24,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -610,7 +726,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 22,
+   "execution_count": 25,
    "metadata": {},
    "outputs": [
     {
@@ -641,7 +757,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 23,
+   "execution_count": 26,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -659,7 +775,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 24,
+   "execution_count": 27,
    "metadata": {},
    "outputs": [
     {
@@ -668,7 +784,7 @@
        "<PackedVectors nvectors=1392, width=306, vdim=3>"
       ]
      },
-     "execution_count": 24,
+     "execution_count": 27,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -686,7 +802,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 25,
+   "execution_count": 28,
    "metadata": {},
    "outputs": [
     {
@@ -695,7 +811,7 @@
        "'-0--------------------RRRRRRFRRRRRRRRRRRFFRFRRRRRRRRRR----------------------------------00-00000001110100011111011010000000000000000011001001100101111110101110110001000100010100110111111101101000000111110011100010111000111R1111111111111111111111110001100100000110100000111010101110RFF00F000F0F00F00000FF01F'"
       ]
      },
-     "execution_count": 25,
+     "execution_count": 28,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -713,7 +829,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 26,
+   "execution_count": 29,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -726,7 +842,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 27,
+   "execution_count": 30,
    "metadata": {},
    "outputs": [
     {
@@ -735,7 +851,7 @@
        "'--F00000F00F0F000F00FF--------------------------------01110101011100000101100000100110R0--0RRRRRRRNNNRNRPRNNNNNRFFRFRRRRRRR000000000011001001100101111110101110110001000100010100110111111101101000000111110011100010111000NNNNNNNNNNNNNNNNNNNNNNNNNNNNP0011001000001101000001110101011101RRRRRRRRRRRRRRRRRRRRP01R'"
       ]
      },
-     "execution_count": 27,
+     "execution_count": 30,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -753,7 +869,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 28,
+   "execution_count": 31,
    "metadata": {},
    "outputs": [
     {
@@ -791,7 +907,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 29,
+   "execution_count": 32,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -811,7 +927,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 30,
+   "execution_count": 33,
    "metadata": {},
    "outputs": [
     {
@@ -820,7 +936,7 @@
        "(46891, 2, 2)"
       ]
      },
-     "execution_count": 30,
+     "execution_count": 33,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -838,7 +954,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 31,
+   "execution_count": 34,
    "metadata": {},
    "outputs": [
     {
@@ -847,7 +963,7 @@
        "119676"
       ]
      },
-     "execution_count": 31,
+     "execution_count": 34,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -875,7 +991,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 32,
+   "execution_count": 35,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -894,7 +1010,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 33,
+   "execution_count": 36,
    "metadata": {},
    "outputs": [
     {
@@ -933,7 +1049,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 34,
+   "execution_count": 37,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -963,7 +1079,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 35,
+   "execution_count": 38,
    "metadata": {},
    "outputs": [
     {
@@ -972,7 +1088,7 @@
        "(306, 128, 7)"
       ]
      },
-     "execution_count": 35,
+     "execution_count": 38,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -990,7 +1106,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 36,
+   "execution_count": 39,
    "metadata": {},
    "outputs": [
     {
@@ -1023,7 +1139,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 37,
+   "execution_count": 40,
    "metadata": {},
    "outputs": [
     {
@@ -1032,7 +1148,7 @@
        "2.0610005855560303"
       ]
      },
-     "execution_count": 37,
+     "execution_count": 40,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -1050,7 +1166,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 38,
+   "execution_count": 41,
    "metadata": {},
    "outputs": [
     {
@@ -1059,7 +1175,7 @@
        "0.0"
       ]
      },
-     "execution_count": 38,
+     "execution_count": 41,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -1077,7 +1193,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 39,
+   "execution_count": 42,
    "metadata": {},
    "outputs": [
     {
@@ -1086,7 +1202,7 @@
        "0.0"
       ]
      },
-     "execution_count": 39,
+     "execution_count": 42,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -1114,7 +1230,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 40,
+   "execution_count": 43,
    "metadata": {},
    "outputs": [
     {
@@ -1136,7 +1252,7 @@
        "True"
       ]
      },
-     "execution_count": 40,
+     "execution_count": 43,
      "metadata": {},
      "output_type": "execute_result"
     }