Add a micrograd on PowerShell sample

samples/Notebooks/powershell/micrograd/Value.format.ps1xml

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+<?xml version="1.0" encoding="utf-8" ?>
+<Configuration>
+  <ViewDefinitions>
+    <View>
+      <Name>Value</Name>
+      <ViewSelectedBy>
+        <TypeName>Value</TypeName>
+      </ViewSelectedBy>
+      <CustomControl>
+        <CustomEntries>
+          <CustomEntry>
+            <CustomItem>
+              <ExpressionBinding>
+                <ScriptBlock>$_.data</ScriptBlock>
+              </ExpressionBinding>
+              <NewLine />
+            </CustomItem>
+          </CustomEntry>
+        </CustomEntries>
+      </CustomControl>
+    </View>
+  </ViewDefinitions>
+</Configuration>

samples/Notebooks/powershell/micrograd/graphHelper.ps1

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+#Requires -Modules @{ ModuleName = 'PSQuickGraph'; ModuleVersion = '2.5.0' }
+#Requires -Modules @{ ModuleName = 'PSGraphView'; ModuleVersion = '0.1.0' }
+
+function New-ValueNode([Value]$value) {
+    [pscustomobject]@{
+        kind  = 'value'
+        value = $value
+        label = $value.label
+        data  = $value.data
+        grad  = $value.grad
+    }
+}
+
+function New-OperationNode([Value]$value) {
+    [pscustomobject]@{
+        kind      = 'op'
+        value     = $value
+        label     = $value.operation
+        operation = $value.operation
+        data      = $value.data
+    }
+}
+
+
+# visualisation
+function New-ExpressionGraph {
+    param(
+        [Value]$val,
+        $graph = $null,
+        [hashtable]$valueVertices = $null,
+        [hashtable]$operationVertices = $null
+    )
+
+    if ($null -eq $graph) {
+        $graph = New-Graph -UseNonUniqueLabels
+    }
+
+    if ($null -eq $valueVertices) {
+        $valueVertices = @{}
+    }
+
+    if ($null -eq $operationVertices) {
+        $operationVertices = @{}
+    }
+
+    if (-not $valueVertices.ContainsKey($val)) {
+        $valueVertices[$val] = Add-Vertex -Graph $graph -Vertex (New-ValueNode $val) -PassThru
+    }
+
+    $valueVertex = $valueVertices[$val]
+
+    if ($val.operation) {
+        if (-not $operationVertices.ContainsKey($val)) {
+            $operationVertices[$val] = Add-Vertex -Graph $graph -Vertex (New-OperationNode $val) -PassThru
+        }
+
+        $operationVertex = $operationVertices[$val]
+
+        Add-Edge -From $operationVertex -To $valueVertex -Graph $graph | Out-Null
+    }
+
+
+    if ($val.children) {
+        foreach ($child in $val.children) {
+            New-ExpressionGraph `
+                -val $child `
+                -graph $graph `
+                -valueVertices $valueVertices `
+                -operationVertices $operationVertices | Out-Null
+
+            $childVertex = $valueVertices[$child]
+
+            if ($val.operation) {
+                Add-Edge -From $childVertex -To $operationVertex -Graph $graph | Out-Null
+            }
+        }
+    }
+
+    return $graph
+}
+
+
+
+# backprop
+function New-BackpropagationGraph {
+    param(
+        [Value]$val,
+        $graph = $null,
+        [hashtable]$valueVertices = $null
+    )
+
+    if ($null -eq $graph) {
+        $graph = New-Graph -UseNonUniqueLabels
+    }
+
+    if ($null -eq $valueVertices) {
+        $valueVertices = @{}
+    }
+
+    if (-not $valueVertices.ContainsKey($val)) {
+        $valueVertices[$val] = Add-Vertex -Graph $graph -Vertex $val -PassThru
+    }
+
+    $currentVertex = $valueVertices[$val]
+
+    foreach ($child in $val.children) {
+        if (-not $valueVertices.ContainsKey($child)) {
+            New-BackpropagationGraph `
+                -Graph $graph `
+                -val $child `
+                -valueVertices $valueVertices | Out-Null
+        }
+
+        $childVertex = $valueVertices[$child]
+        Add-Edge -Graph $graph -From $childVertex -To $currentVertex | Out-Null
+    }
+
+    return $graph
+}
+
+
+function Show-ExpressionGraph {
+    param (
+        $graph,
+        $rankdir = "LR"
+    )
+
+    begin {
+        # node formatting lambda
+
+        $vs = {
+            $node = $_
+
+            if ($node.kind -eq 'op') {
+                @{
+                    shape = 'Ellipse'
+                    label = $node.label
+                }
+            }
+            else {
+                $name = if ($node.label) { $node.label } else { '' }
+
+                @{
+                    shape = 'Record'
+                    label = "{ $name | data $($node.data) | grad $($node.grad) }"
+                }
+            }
+        }
+
+        $dot = Export-Graph -Graph $graph -Format Graphviz -GraphScript { @{ rankdir = $rankdir; label = 'Micrograd' } } -VertexScript $vs
+
+        $svg = Export-GraphvizView -InputObject $dot -Renderer Dot -As Svg
+        Display $svg 'image/svg+xml'
+    }
+
+    process {
+
+    }
+
+    end {
+
+    }
+}

samples/Notebooks/powershell/micrograd/helpers.ps1

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+function Zip {
+    param(
+        [Parameter(Mandatory)]
+        [object[]]$Left,
+
+        [Parameter(Mandatory)]
+        [object[]]$Right
+    )
+
+    $count = [Math]::Min($Left.Count, $Right.Count)
+
+    for ($i = 0; $i -lt $count; $i++) {
+        [pscustomobject]@{
+            Left  = $Left[$i]
+            Right = $Right[$i]
+        }
+    }
+}
+
+function Sum-Value {
+    param([scriptblock]$Selector)
+
+    begin { $sum = [Value]::new(0.0, 'loss') }
+    process { $sum = $sum + (& $Selector $_) }
+    end { $sum }
+}