use IReadOnly result inputs

src/_common/Generics/Pruning.cs

@@ -6,7 +6,7 @@ public static partial class Utility
 {
     // REMOVE SPECIFIC PERIODS
     public static IReadOnlyList<T> RemoveWarmupPeriods<T>(
-        this IEnumerable<T> series,
+        this IReadOnlyList<T> series,
         int removePeriods)
         => removePeriods < 0
             ? throw new ArgumentOutOfRangeException(nameof(removePeriods), removePeriods,
@@ -15,7 +15,7 @@ public static IReadOnlyList<T> RemoveWarmupPeriods<T>(
 
     // REMOVE PERIODS
     internal static List<T> Remove<T>(
-        this IEnumerable<T> series,
+        this IReadOnlyList<T> series,
         int removePeriods)
     {
         List<T> seriesList = series.ToList();

src/_common/Generics/Transforms.cs

@@ -9,10 +9,7 @@ public static partial class Utility
     // TO COLLECTION
     internal static Collection<T> ToCollection<T>(this IEnumerable<T> source)
     {
-        if (source is null)
-        {
-            throw new ArgumentNullException(nameof(source));
-        }
+        ArgumentNullException.ThrowIfNull(source);
 
         Collection<T> collection = [.. source];
 

src/_common/Math/Numerical.cs

@@ -5,13 +5,8 @@ public static class Numerical
     // STANDARD DEVIATION
     public static double StdDev(this double[] values)
     {
-        // validate parameters
-        if (values is null)
-        {
-            throw new ArgumentNullException(
-                nameof(values),
-                "StdDev values cannot be null.");
-        }
+        ArgumentNullException.ThrowIfNull(
+            values, "StdDev values cannot be null.");
 
         int n = values.Length;
 
@@ -43,17 +38,8 @@ public static double StdDev(this double[] values)
     public static double Slope(double[] x, double[] y)
     {
         // validate parameters
-        if (x is null)
-        {
-            throw new ArgumentNullException(
-                nameof(x), "Slope X values cannot be null.");
-        }
-
-        if (y is null)
-        {
-            throw new ArgumentNullException(
-                nameof(y), "Slope Y values cannot be null.");
-        }
+        ArgumentNullException.ThrowIfNull(x, "Slope X values cannot be null.");
+        ArgumentNullException.ThrowIfNull(y, "Slope Y values cannot be null.");
 
         if (x.Length != y.Length)
         {

src/_common/ObsoleteV3.cs

@@ -33,7 +33,7 @@ public static IEnumerable<AlligatorResult> GetAlligator(
     public static IEnumerable<EmaResult> GetEma<TQuote>(
         this IEnumerable<TQuote> quotes, int lookbackPeriods)
         where TQuote : IQuote
-        => Api.GetEma(quotes, lookbackPeriods);
+        => quotes.ToSortedList().ToEma(lookbackPeriods);
 
     // REMOVAL OF INTEGRATED SMAs (evaluates to ERRORs)
 

src/_common/Quotes/Quote.Converters.cs

@@ -6,8 +6,6 @@ namespace Skender.Stock.Indicators;
 
 public static partial class Utility
 {
-    private static readonly CultureInfo NativeCulture = Thread.CurrentThread.CurrentUICulture;
-
     /* LISTS */
 
     // convert TQuote type list to built-in Quote type list

src/_common/Quotes/Quote.Validation.cs

@@ -2,38 +2,10 @@
 
 namespace Skender.Stock.Indicators;
 
-// QUOTE UTILITIES
+// QUOTE UTILITIES: VALIDATION
 
 public static partial class Utility
 {
-    // VALIDATION
-    /// <include file='./info.xml' path='info/type[@name="Validate"]/*' />
-    ///
-    public static IReadOnlyList<TQuote> Validate<TQuote>(
-        this IEnumerable<TQuote> quotes)
-        where TQuote : IQuote
-    {
-        // we cannot rely on date consistency when looking back, so we force sort
-
-        List<TQuote> quotesList = quotes.ToSortedList();
-
-        // check for duplicates
-        DateTime lastDate = DateTime.MinValue;
-        foreach (TQuote q in quotesList)
-        {
-            // check for duplicates
-            if (lastDate == q.Timestamp)
-            {
-                throw new InvalidQuotesException(
-                    string.Format(NativeCulture, "Duplicate date found on {0}.", q.Timestamp));
-            }
-
-            lastDate = q.Timestamp;
-        }
-
-        return quotesList;
-    }
-
     /// <summary>
     /// Check that quotes are valid and in ascending order.
     /// </summary>
@@ -50,34 +22,33 @@ public static IReadOnlyList<TQuote> Validate<TQuote>(
         this IReadOnlyList<TQuote> quotes)
         where TQuote : IQuote
     {
-        // assumes already sorted
-        if (quotes is null)
+        ArgumentNullException.ThrowIfNull(quotes);
+
+        if (quotes.Count == 0)
         {
-            throw new ArgumentNullException(nameof(quotes));
+            return quotes;
         }
 
-        // check for duplicates/sequence
-        DateTime lastDate = DateTime.MinValue;
-        foreach (TQuote q in quotes)
+        DateTime lastDate = quotes[0].Timestamp;
+        for (int i = 1; i < quotes.Count; i++)
         {
-            // check for duplicates
-            if (lastDate == q.Timestamp)
+            DateTime currentDate = quotes[i].Timestamp;
+
+            if (lastDate == currentDate)
             {
                 throw new InvalidQuotesException(
-                    string.Format(CultureInfo.InvariantCulture, "Duplicate date found on {0}.", q.Timestamp));
+                    string.Format(CultureInfo.InvariantCulture, "Duplicate date found on {0}.", currentDate));
             }
 
-            // check for sequence
-            if (lastDate > q.Timestamp)
+            if (lastDate > currentDate)
             {
                 throw new InvalidQuotesException(
-                    string.Format(NativeCulture, "Quotes are out of sequence on {0}.", q.Timestamp));
+                    string.Format(CultureInfo.InvariantCulture, "Quotes are out of sequence on {0}.", currentDate));
             }
 
-            lastDate = q.Timestamp;
+            lastDate = currentDate;
         }
 
         return quotes;
     }
-
 }

src/_common/Quotes/info.xml

@@ -2,21 +2,6 @@
 
 <info>
 
-  <type name="Validate">
-    <summary>
-      Validate historical quotes.
-      <para>
-        See
-        <see href="https://dotnet.StockIndicators.dev/utilities/#validate-quote-history?utm_source=library&amp;utm_medium=inline-help&amp;utm_campaign=embedded">documentation</see>
-        for more information.
-      </para>
-    </summary>
-    <typeparam name="TQuote">Configurable Quote type.  See Guide for more information.</typeparam>
-    <param name="quotes">Historical price quotes.</param>
-    <returns>Time series of historical quote values.</returns>
-    <exception cref="InvalidQuotesException">Validation check failed.</exception>
-  </type>
-
   <type name="Aggregate">
     <summary>
       Converts historical quotes into larger bar sizes.
@@ -49,4 +34,4 @@
     <exception cref="ArgumentOutOfRangeException">Invalid parameter value provided.</exception>
   </type>
 
-</info>
+</info>

src/_common/Reusable/Reusable.Utilities.cs

@@ -26,7 +26,7 @@ public static IReadOnlyList<IReusable> ToReusableList<TQuote>(
     /// <param name="results">Indicator results to evaluate.</param>
     /// <returns>Time series of indicator results, condensed.</returns>
     public static IReadOnlyList<T> Condense<T>(
-        this IEnumerable<T> results)
+        this IReadOnlyList<T> results)
         where T : IReusable
     {
         List<T> resultsList = results
@@ -37,9 +37,6 @@ public static IReadOnlyList<T> Condense<T>(
                 x => double.IsNaN(x.Value));
 
         return resultsList;
-
-        // TODO: remove specific indicator 'Condense()' methods
-        // that are now redundant to this generic method (not all are)
     }
 
     /// <summary>
@@ -54,7 +51,7 @@ public static IReadOnlyList<T> Condense<T>(
     /// <param name="results">Indicator results to evaluate.</param>
     /// <returns>Time series of results, pruned.</returns>
     internal static IReadOnlyList<T> RemoveWarmupPeriods<T>(
-        this IEnumerable<T> results)
+        this IReadOnlyList<T> results)
         where T : IReusable
     {
         // this is the default implementation, it will

src/a-d/Adx/Adx.Utilities.cs

@@ -3,9 +3,9 @@ namespace Skender.Stock.Indicators;
 public static partial class Indicator
 {
     // remove recommended periods
-    /// <inheritdoc cref="Utility.RemoveWarmupPeriods{T}(IEnumerable{T})"/>
+    /// <inheritdoc cref="Utility.RemoveWarmupPeriods{T}(IReadOnlyList{T})"/>
     public static IReadOnlyList<AdxResult> RemoveWarmupPeriods(
-        this IEnumerable<AdxResult> results)
+        this IReadOnlyList<AdxResult> results)
     {
         int n = results
             .ToList()

src/a-d/Alligator/Alligator.Utilities.cs

@@ -18,7 +18,7 @@ public static IReadOnlyList<AlligatorResult> Condense(
 
     // remove recommended periods
     public static IReadOnlyList<AlligatorResult> RemoveWarmupPeriods(
-        this IEnumerable<AlligatorResult> results)
+        this IReadOnlyList<AlligatorResult> results)
     {
         int removePeriods = results
           .ToList()

src/a-d/Alma/Alma.Api.cs

@@ -5,7 +5,7 @@ public static partial class Indicator
 {
     // SERIES, from CHAIN
     public static IReadOnlyList<AlmaResult> GetAlma<T>(
-        this IEnumerable<T> results,
+        this IReadOnlyList<T> results,
         int lookbackPeriods = 9,
         double offset = 0.85,
         double sigma = 6)

src/a-d/Alma/Alma.Utilities.cs

@@ -3,9 +3,9 @@ namespace Skender.Stock.Indicators;
 public static partial class Indicator
 {
     // remove recommended periods
-    /// <inheritdoc cref="Utility.RemoveWarmupPeriods{T}(IEnumerable{T})"/>
+    /// <inheritdoc cref="Utility.RemoveWarmupPeriods{T}(IReadOnlyList{T})"/>
     public static IReadOnlyList<AlmaResult> RemoveWarmupPeriods(
-        this IEnumerable<AlmaResult> results)
+        this IReadOnlyList<AlmaResult> results)
     {
         int removePeriods = results
             .ToList()

src/a-d/Aroon/Aroon.Utilities.cs

@@ -3,9 +3,9 @@ namespace Skender.Stock.Indicators;
 public static partial class Indicator
 {
     // remove recommended periods
-    /// <inheritdoc cref="Utility.RemoveWarmupPeriods{T}(IEnumerable{T})"/>
+    /// <inheritdoc cref="Utility.RemoveWarmupPeriods{T}(IReadOnlyList{T})"/>
     public static IReadOnlyList<AroonResult> RemoveWarmupPeriods(
-        this IEnumerable<AroonResult> results)
+        this IReadOnlyList<AroonResult> results)
     {
         int removePeriods = results
             .ToList()

src/a-d/Atr/Atr.Utilities.cs

@@ -41,7 +41,7 @@ public static AtrResult Increment<TQuote>(
 
     // remove recommended periods
     public static IReadOnlyList<AtrResult> RemoveWarmupPeriods(
-        this IEnumerable<AtrResult> results)
+        this IReadOnlyList<AtrResult> results)
     {
         int removePeriods = results
             .ToList()

src/a-d/AtrStop/AtrStop.Utilities.cs

@@ -5,9 +5,9 @@ namespace Skender.Stock.Indicators;
 public static partial class AtrStop
 {
     // CONDENSE (REMOVE null results)
-    /// <inheritdoc cref="Utility.Condense{T}(IEnumerable{T})"/>
+    /// <inheritdoc cref="Utility.Condense{T}(IReadOnlyList{T})"/>
     public static IReadOnlyList<AtrStopResult> Condense(
-        this IEnumerable<AtrStopResult> results)
+        this IReadOnlyList<AtrStopResult> results)
     {
         List<AtrStopResult> resultsList = results
             .ToList();
@@ -18,9 +18,9 @@ public static IReadOnlyList<AtrStopResult> Condense(
     }
 
     // remove recommended periods
-    /// <inheritdoc cref="Utility.RemoveWarmupPeriods{T}(IEnumerable{T})"/>
+    /// <inheritdoc cref="Utility.RemoveWarmupPeriods{T}(IReadOnlyList{T})"/>
     public static IReadOnlyList<AtrStopResult> RemoveWarmupPeriods(
-        this IEnumerable<AtrStopResult> results)
+        this IReadOnlyList<AtrStopResult> results)
     {
         int removePeriods = results
             .ToList()

src/a-d/Awesome/Awesome.Utilities.cs

@@ -3,9 +3,9 @@ namespace Skender.Stock.Indicators;
 public static partial class Indicator
 {
     // remove recommended periods
-    /// <inheritdoc cref="Utility.RemoveWarmupPeriods{T}(IEnumerable{T})"/>
+    /// <inheritdoc cref="Utility.RemoveWarmupPeriods{T}(IReadOnlyList{T})"/>
     public static IReadOnlyList<AwesomeResult> RemoveWarmupPeriods(
-        this IEnumerable<AwesomeResult> results)
+        this IReadOnlyList<AwesomeResult> results)
     {
         int removePeriods = results
             .ToList()

src/a-d/Beta/Beta.Utilities.cs

@@ -3,9 +3,9 @@ namespace Skender.Stock.Indicators;
 public static partial class Indicator
 {
     // remove recommended periods
-    /// <inheritdoc cref="Utility.RemoveWarmupPeriods{T}(IEnumerable{T})"/>
+    /// <inheritdoc cref="Utility.RemoveWarmupPeriods{T}(IReadOnlyList{T})"/>
     public static IReadOnlyList<BetaResult> RemoveWarmupPeriods(
-        this IEnumerable<BetaResult> results)
+        this IReadOnlyList<BetaResult> results)
     {
         int removePeriods = results
             .ToList()

src/a-d/BollingerBands/BollingerBands.Api.cs

@@ -5,7 +5,7 @@ public static partial class Indicator
 {
     // SERIES, from CHAIN
     public static IReadOnlyList<BollingerBandsResult> GetBollingerBands<T>(
-        this IEnumerable<T> results,
+        this IReadOnlyList<T> results,
         int lookbackPeriods = 20,
         double standardDeviations = 2)
         where T : IReusable

src/a-d/BollingerBands/BollingerBands.Utilities.cs

@@ -3,9 +3,9 @@ namespace Skender.Stock.Indicators;
 public static partial class Indicator
 {
     // remove recommended periods
-    /// <inheritdoc cref="Utility.RemoveWarmupPeriods{T}(IEnumerable{T})"/>
+    /// <inheritdoc cref="Utility.RemoveWarmupPeriods{T}(IReadOnlyList{T})"/>
     public static IReadOnlyList<BollingerBandsResult> RemoveWarmupPeriods(
-        this IEnumerable<BollingerBandsResult> results)
+        this IReadOnlyList<BollingerBandsResult> results)
     {
         int removePeriods = results
             .ToList()

src/a-d/Bop/Bop.Utilities.cs

@@ -3,9 +3,9 @@ namespace Skender.Stock.Indicators;
 public static partial class Indicator
 {
     // remove recommended periods
-    /// <inheritdoc cref="Utility.RemoveWarmupPeriods{T}(IEnumerable{T})"/>
+    /// <inheritdoc cref="Utility.RemoveWarmupPeriods{T}(IReadOnlyList{T})"/>
     public static IReadOnlyList<BopResult> RemoveWarmupPeriods(
-        this IEnumerable<BopResult> results)
+        this IReadOnlyList<BopResult> results)
     {
         int removePeriods = results
             .ToList()

src/a-d/Cci/Cci.Utilities.cs

@@ -3,9 +3,9 @@ namespace Skender.Stock.Indicators;
 public static partial class Indicator
 {
     // remove recommended periods
-    /// <inheritdoc cref="Utility.RemoveWarmupPeriods{T}(IEnumerable{T})"/>
+    /// <inheritdoc cref="Utility.RemoveWarmupPeriods{T}(IReadOnlyList{T})"/>
     public static IReadOnlyList<CciResult> RemoveWarmupPeriods(
-        this IEnumerable<CciResult> results)
+        this IReadOnlyList<CciResult> results)
     {
         int removePeriods = results
             .ToList()

src/a-d/ChaikinOsc/ChaikinOsc.StaticSeries.cs

@@ -21,8 +21,8 @@ private static List<ChaikinOscResult> CalcChaikinOsc<TQuote>(
         List<AdlResult> adlResults = source.CalcAdl();
 
         // fast/slow EMA of ADL
-        List<EmaResult> adlEmaSlow = adlResults.CalcEma(slowPeriods);
-        List<EmaResult> adlEmaFast = adlResults.CalcEma(fastPeriods);
+        IReadOnlyList<EmaResult> adlEmaSlow = adlResults.ToEma(slowPeriods);
+        IReadOnlyList<EmaResult> adlEmaFast = adlResults.ToEma(fastPeriods);
 
         // roll through source values
         for (int i = 0; i < length; i++)