Fix bad layout by properly placing decoupling caps (Fixes #12)

lib/solvers/ChipPartitionsSolver/ChipPartitionsSolver.ts

@@ -60,7 +60,8 @@ export class ChipPartitionsSolver extends BaseSolver {
           }
         }
         // Only add a partition if there are at least two caps present in the inputProblem
-        if (capsOnly.length >= 2) {
+        // We disabled this to allow PlaceDecouplingCapsSolver to place them around the main chip
+        if (false) {
           decapGroupPartitions.push(capsOnly)
           // Mark these caps as handled by decoupling-cap partitions
           for (const capId of capsOnly) {

lib/solvers/LayoutPipelineSolver/LayoutPipelineSolver.ts

@@ -7,6 +7,7 @@ import type { GraphicsObject } from "graphics-debug"
 import { BaseSolver } from "lib/solvers/BaseSolver"
 import { ChipPartitionsSolver } from "lib/solvers/ChipPartitionsSolver/ChipPartitionsSolver"
 import { IdentifyDecouplingCapsSolver } from "lib/solvers/IdentifyDecouplingCapsSolver/IdentifyDecouplingCapsSolver"
+import { PlaceDecouplingCapsSolver } from "lib/solvers/PlaceDecouplingCapsSolver/PlaceDecouplingCapsSolver"
 import {
   PackInnerPartitionsSolver,
   type PackedPartition,
@@ -50,6 +51,7 @@ function definePipelineStep<
 
 export class LayoutPipelineSolver extends BaseSolver {
   identifyDecouplingCapsSolver?: IdentifyDecouplingCapsSolver
+  placeDecouplingCapsSolver?: PlaceDecouplingCapsSolver
   chipPartitionsSolver?: ChipPartitionsSolver
   packInnerPartitionsSolver?: PackInnerPartitionsSolver
   partitionPackingSolver?: PartitionPackingSolver
@@ -77,6 +79,22 @@ export class LayoutPipelineSolver extends BaseSolver {
         },
       },
     ),
+    definePipelineStep(
+      "placeDecouplingCapsSolver",
+      PlaceDecouplingCapsSolver,
+      () => [
+        {
+          inputProblem: this.inputProblem,
+          decouplingCapGroups:
+            this.identifyDecouplingCapsSolver?.outputDecouplingCapGroups || [],
+        },
+      ],
+      {
+        onSolved: (_layoutSolver) => {
+          // Decoupling caps placed around main chip
+        },
+      },
+    ),
     definePipelineStep(
       "chipPartitionsSolver",
       ChipPartitionsSolver,
@@ -196,6 +214,7 @@ export class LayoutPipelineSolver extends BaseSolver {
 
     const identifyDecouplingCapsViz =
       this.identifyDecouplingCapsSolver?.visualize()
+    const placeDecouplingCapsViz = this.placeDecouplingCapsSolver?.visualize()
     const chipPartitionsViz = this.chipPartitionsSolver?.visualize()
     const packInnerPartitionsViz = this.packInnerPartitionsSolver?.visualize()
     const partitionPackingViz = this.partitionPackingSolver?.visualize()
@@ -207,6 +226,7 @@ export class LayoutPipelineSolver extends BaseSolver {
     const visualizations = [
       inputViz,
       identifyDecouplingCapsViz,
+      placeDecouplingCapsViz,
       chipPartitionsViz,
       packInnerPartitionsViz,
       partitionPackingViz,
@@ -262,6 +282,9 @@ export class LayoutPipelineSolver extends BaseSolver {
     if (this.chipPartitionsSolver?.solved) {
       return this.chipPartitionsSolver.visualize()
     }
+    if (this.placeDecouplingCapsSolver?.solved) {
+      return this.placeDecouplingCapsSolver.visualize()
+    }
     if (this.identifyDecouplingCapsSolver?.solved) {
       return this.identifyDecouplingCapsSolver.visualize()
     }

lib/solvers/PlaceDecouplingCapsSolver/PlaceDecouplingCapsSolver.ts

@@ -0,0 +1,123 @@
+import { BaseSolver } from "../BaseSolver"
+import type { InputProblem, ChipId, NetId, Chip } from "lib/types/InputProblem"
+import type { DecouplingCapGroup } from "../IdentifyDecouplingCapsSolver/IdentifyDecouplingCapsSolver"
+import type { GraphicsObject } from "graphics-debug"
+
+export class PlaceDecouplingCapsSolver extends BaseSolver {
+  inputProblem: InputProblem
+  decouplingCapGroups: DecouplingCapGroup[]
+
+  constructor(params: {
+    inputProblem: InputProblem
+    decouplingCapGroups: DecouplingCapGroup[]
+  }) {
+    super()
+    this.inputProblem = params.inputProblem
+    this.decouplingCapGroups = params.decouplingCapGroups
+  }
+
+  override _step() {
+    // Determine placement for each decoupling capacitor
+    const GAP = 0.5
+    // To avoid overlapping caps on the same pin, keep track of how many caps we've placed per pin
+    const pinCapCount: Record<string, number> = {}
+
+    for (const group of this.decouplingCapGroups) {
+      const mainChip = this.inputProblem.chipMap[group.mainChipId]
+      if (!mainChip) continue
+
+      // Set the main chip to be fixed at 0,0 if it isn't already fixed
+      if (!mainChip.fixedPosition) {
+        mainChip.fixedPosition = { x: 0, y: 0 }
+      }
+
+      for (const capId of group.decouplingCapChipIds) {
+        const cap = this.inputProblem.chipMap[capId]
+        if (!cap) continue
+
+        // Find the pin on the main chip that this cap is strongly connected to
+        let connectedPinOnMainChip: string | null = null
+
+        for (const capPinId of cap.pins) {
+          for (const [connKey, isConnected] of Object.entries(
+            this.inputProblem.pinStrongConnMap,
+          )) {
+            if (!isConnected) continue
+            const [p1, p2] = connKey.split("-")
+            if (p1 === capPinId && p2?.startsWith(`${group.mainChipId}.`)) {
+              connectedPinOnMainChip = p2
+              break
+            }
+            if (p2 === capPinId && p1?.startsWith(`${group.mainChipId}.`)) {
+              connectedPinOnMainChip = p1
+              break
+            }
+          }
+          if (connectedPinOnMainChip) break
+        }
+
+        if (connectedPinOnMainChip) {
+          const mainPin = this.inputProblem.chipPinMap[connectedPinOnMainChip]
+          if (mainPin) {
+            const side = mainPin.side
+            const offset = mainPin.offset
+            const mainChipPos = mainChip.fixedPosition
+
+            pinCapCount[connectedPinOnMainChip] =
+              (pinCapCount[connectedPinOnMainChip] || 0) + 1
+            const count = pinCapCount[connectedPinOnMainChip]!
+            const shift = (count - 1) * (Math.max(cap.size.x, cap.size.y) + 0.2)
+
+            let capX = mainChipPos.x + offset.x
+            let capY = mainChipPos.y + offset.y
+            let rotation = 0
+
+            if (side === "x-") {
+              capX -= cap.size.x / 2 + GAP
+              capY += shift
+            } else if (side === "x+") {
+              capX += cap.size.x / 2 + GAP
+              capY += shift
+            } else if (side === "y+") {
+              capY += cap.size.y / 2 + GAP
+              capX += shift
+              rotation = 90
+            } else if (side === "y-") {
+              capY -= cap.size.y / 2 + GAP
+              capX += shift
+              rotation = 90
+            }
+
+            cap.fixedPosition = { x: capX, y: capY }
+            if (!cap.availableRotations) {
+              cap.availableRotations = [rotation as any]
+            } else {
+              cap.availableRotations = [rotation as any]
+            }
+          }
+        }
+      }
+    }
+
+    this.solved = true
+  }
+
+  override visualize(): GraphicsObject {
+    return {
+      points: [],
+      rects: [],
+      lines: [],
+      circles: [],
+      texts: [],
+    }
+  }
+
+  override getConstructorParams() {
+    return [
+      {
+        inputProblem: this.inputProblem,
+        decouplingCapGroups: this.decouplingCapGroups,
+      },
+    ]
+  }
+}