NREL mismatch loss addendum

docs/examples/bifacial/plot_irradiance_nonuniformity_loss.py

@@ -100,13 +100,12 @@
 #
 
 
-def rmad(data, axis=None):
+def rmad(data):
     """
-    Relative Mean Absolute Difference. Output is [Unitless].
-    https://stackoverflow.com/a/19472336/19371110
+    Relative Mean Absolute Difference. Output is [Unitless]. Eq. (4) of [1]_.
     """
-    mean = np.mean(data, axis)
-    mad = np.mean(np.absolute(data - mean), axis)
+    mean = np.mean(data)
+    mad = np.mean(np.absolute(np.subtract.outer(data, data)))
     return mad / mean
 
 

docs/sphinx/source/whatsnew/v0.11.1.rst

@@ -41,6 +41,8 @@ Requirements
 
 Contributors
 ~~~~~~~~~~~~
+* Echedey Luis (:ghuser:`echedey-ls`)
+* Chris Deline (:ghuser:`cdeline`)
 * Ioannis Sifnaios (:ghuser:`IoannisSifnaios`)
 * Leonardo Micheli (:ghuser:`lmicheli`)
 * Echedey Luis (:ghuser:`echedey-ls`)

pvlib/bifacial/loss_models.py

@@ -71,7 +71,7 @@ def power_mismatch_deline(
     where the upper equation is in percentage (same as paper) and the lower
     one is unitless. The implementation uses the unitless version, where
     :math:`M[-]` is the mismatch power loss [unitless] and
-    :math:`\Delta[-]` is the Relative Mean Absolute Difference [unitless]
+    :math:`\Delta[-]` is the Relative Mean Absolute Difference (RMAD) [unitless]
     of the global irradiance, Eq. (4) of [1]_ and [2]_.
     Note that the n-th power coefficient is multiplied by :math:`100^{n-1}`
     to convert the percentage to unitless.
@@ -101,6 +101,14 @@ def power_mismatch_deline(
        The global irradiance RMAD is different from the backside irradiance
        RMAD.
 
+    RMAD of a variable :math:`G_{total}` is defined as:
+
+    .. math::
+
+        RMAD \left[ unitless \right] = \Delta \left[ unitless \right] =
+        \frac{1}{n^2 \bar{G}_{total}} \sum_{i=1}^{n} \sum_{j=1}^{n}
+        \lvert G_{total,i} - G_{total,j} \rvert
+
     In case the RMAD of the backside irradiance is known, the global RMAD can
     be calculated as follows, assuming the front irradiance RMAD is
     negligible [2]_: