Jsl/make layer stack v2 #79

lchao-jitx · 2024-07-12T17:02:09Z

Revert the last commit for 'Enhance make-layer-stack to handle multiple adjacent prepreg layers'
and then re-commit it for review.
- This commit also removes the reference to JLCPCB in the examples/tests for layer-stack so that a generic 4-layer stack is used.
Revise verify-layers to handle even number of layers in a stack.

In summary, the make-layer-stack is revised to support these two examples:

    make-layer-stack("4-layer stack with three adjacent prepreg layers", top-layers) where :
      val top-layers =  [
        [copper-35um [prepreg prepreg2 prepreg3]]
        [copper-17_5um core]
      ]

and

    make-layer-stack("6-layer stack with even number of layers", outers, even-layers? = true) where :
      val outers =
        [
          [copper-35um prepreg]
          [copper-17_5um core]
          [copper-17_5um prepreg2] ; => two layers of prepreg2 in the center
        ]

…adjacent pregpreg layers'

…jacent repreg layers.'

lchao-jitx · 2024-07-12T17:10:33Z

On second thought, maybe a better method to support multiple adjacent prepreg layers is:

    val stack = make-layer-stack("4-layer with two adjacent prepreg layers", top-layers) where :
      val top-layers =  [
        [copper-35um prepreg prepreg]
        [copper-17_5um core]
      ]

rather than what I have in the last commit: 'Enhance make-layer-stack ...'

    val stack = make-layer-stack("4-layer with two adjacent prepreg layers", top-layers) where :
      val top-layers =  [
        [copper-35um prepreg]
        prepreg
        [copper-17_5um core]
      ]

callendorph · 2024-07-12T17:23:34Z

I would prefer that we consider the following:

    val stack = make-layer-stack("4-layer with two adjacent prepreg layers", top-layers) where :
      val top-layers =  [
        [copper-35um [prepreg prepreg] ]
        [copper-17_5um core]
      ]

Because they we can add a function like:

defn make-multi-ply (m:Material, num-ply:Int ) -> Tuple<Material> : 
  to-tuple $ for i in 0 to num-ply seq:
      m

defn make-double-ply (m:Material) -> Tuple<Material> : 
  make-multi-ply(m, 2)

And this ends up looking more like:

    val prepreg-x2 = make-dual-ply(prepreg)
    val stack = make-layer-stack("4-layer with two adjacent prepreg layers", top-layers) where :
      val top-layers =  [
        [copper-35um prepreg-x2 ]
        [copper-17_5um core]
      ]

This was we can prevent the introduction of touching copper layers by design and we can support multiple pre-preg layers as necessary.

lchao-jitx · 2024-07-12T18:14:56Z

I found that some 6-layer JLCPCB stakcups have an even number of layers, such as "JLC061211-2116", "JLC061211-2116" , "JLC06201H-3313A", "JLC062011-7628", "JLC062011-3313", "JLC062011-1080" etc.
The version in the last commit works for those cases since whenever it is a single LayerSpec, it is added to both the top and the bottom of the stack.

For example,

  val test-stack = make-layer-stack("JLC06201H-3313A", outers) where :
  val core = FR4("core", 0.7, "core")
  val prepreg = FR4("2116", 0.1164, "2116*1")
  val prepregA = FR4("3313", 0.0994, "3313*1")
  val outers =
    [
      [copper-35um prepreg]
      [copper-15_2um core]
      copper-15_2um
      prepregA       ; => two layers of prepregA in the center
    ]

lchao-jitx · 2024-07-12T18:36:16Z

The two adjacent prepreg layers may not be the same though.
Here is an example with three different adjacent prepreg layers:

We could support it this way.

protected val stack = make-layer-stack("JLC04161H-2116A", outers) where :
  val core = FR4("core", 0.6, "core")
  val prepreg = FR4("2116", 0.124, "2116*1")
  val prepregA = FR4("7628", 0.218, "7628*1")
  val prepregB = FR4("2116", 0.1164, "2116*1")
  val outers = 
    [ 
      [copper-35um [prepreg prepregA prepregB]]
      [copper-15_2um core]
    ]

lchao-jitx · 2024-07-12T18:42:28Z

For the case when there are even number of layers (no one center layer), perhaps we can support it this way:

val test-stack = make-layer-stack("JLC06201H-3313A", outers) where :
  val core = FR4("core", 0.7, "core")
  val prepreg = FR4("2116", 0.1164, "2116*1")
  val prepregA = FR4("3313", 0.0994, "3313*1")
  val outers =
    [
      [copper-35um prepreg]
      [copper-15_2um core]
      [copper-15_2um [prepregA]]       ; => two layers of prepregA in the center
    ]

To use [copper-15_2um [prepregA]], rather than [copper-15_2um prepregA].

But then, maybe it is better to just use an optional flag even-layers?, like I used for verify-layers function.
This way it's more explicit for the user.

[Edit] Strike above comment.
I have implemented it with an optional flag even-layers? and committed the code with this change.

… that.

lchao-jitx · 2024-07-12T21:38:30Z

The make-layer-stack is revised to support these two examples:

    make-layer-stack("4-layer stack with three adjacent prepreg layers", top-layers) where :
      val top-layers =  [
        [copper-35um [prepreg prepreg2 prepreg3]]
        [copper-17_5um core]
      ]

and

    make-layer-stack("6-layer stack with even number of layers", outers, even-layers? = true) where :
      val outers =
        [
          [copper-35um prepreg]
          [copper-17_5um core]
          [copper-17_5um prepreg2] ; => two layers of prepreg2 in the center
        ]

…], rather than error out. Add test when there are multiple prepreg layers in the middle

src/layerstack.stanza

callendorph · 2024-07-16T21:28:59Z

src/layerstack.stanza

+     ]
+    ```
+
+  Example 3: 6-layer stack with even number of layers, such as "JLC06201H-3313A"


For examples 1, 2, 3 - let's please use the @snippet marker and related @snip-note marker syntax here for the docstrings.

See here for more details:
https://jit-x.slack.com/docs/TKJEB34LS/F05RW135Y0J

callendorph · 2024-07-16T21:31:10Z

src/layerstack.stanza

+
+  Example 3: 6-layer stack with even number of layers, such as "JLC06201H-3313A"
+  ```
+    make-layer-stack("6-layer stack with even number of layers", outers, even-layers? = true) where :


Why would we do this ?
Why would we not just continue using the pattern we have already established?

For example:

val outers = [ [copper-35um prepreg] [copper-17_5um core] [copper-17_5um [prepreg2, prepreg2]] ; => two layers of prepreg2 in the center ]

I would much prefer this than even-layers? which is difficult to explain and requires additional handling.

callendorph · 2024-07-16T21:47:14Z

src/layerstack.stanza

+          add-top(reverse(layers), stack) ; ordered from inner to outer
+          add-bottom(reverse(layers), stack)
+    else : ; even-layers? = true
+      if outer[1] is LayerSpec :


Can we please use a match statement instead of using if ... is ?

The if ... is is an anti-pattern in stanza and the idiomatic mechanism is the match clause.

callendorph · 2024-07-16T21:48:59Z

src/layerstack.stanza

+        if n-insuls == 1 : ; [copper [dielectric]] => treat it as [copper dielectric]
+          add-symmetric(metal, insuls[0], stack)
+        else :
+          add-symmetric(insuls[n-insuls - 2], insuls[n-insuls - 1], stack)


This doesn't look right. What happens if n-insuls is greater than 3 ?

callendorph · 2024-07-16T21:49:25Z

src/layerstack.stanza

+    ;Verify input
+    if outer[1] is Tuple<LayerSpec> and empty?(outer[1] as Tuple<LayerSpec>) :
+      throw(Exception("Invalid argument: The tuple of dialectric layers is empty. Expect [LayerSpec Tuple<LayerSpec>]. Found %_" % [outer]))
+    if not even-layers? :


The even-layers? parameter here is making this function about 1000x more complicated than this needs to be.

We need to remove this.

lchao-jitx · 2024-07-17T16:35:37Z

Please see the third version of make-layer-stack in #92 with a much simplified interface and logic.

I have incorporated changes to address the comments in this PR there too.

lchao-jitx · 2024-07-25T17:34:19Z

Dropping this PR since the third version of make-layer-stack in this other PR has a much cleaner interface.

Liang Chao added 3 commits July 12, 2024 09:50

revert the last commit: 'Enhance make-layer-stack to handle multiple …

9079edd

…adjacent pregpreg layers'

redo the last commit: 'Enhance make-layer-stack to handle multiple ad…

878001e

…jacent repreg layers.'

Revise verify-layers to support even number of layers in a stack

5aa4d47

lchao-jitx requested review from callendorph and emspin July 12, 2024 17:02

lchao-jitx requested a review from bhusang July 12, 2024 17:17

Liang Chao added 2 commits July 12, 2024 14:31

Revised to supprt even number of layers. Added test and docstring for…

4cae6d9

… that.

Simplied examples in docstring a bit for make-layer-stack

5ef796c

Revise to treat [copper [dielectric]] the same as [copper dielelctric…

e14c8b8

…], rather than error out. Add test when there are multiple prepreg layers in the middle