id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
5232	Unexpanded array() in function algorithm prevents differentiation when using the NF	Francesco Casella	Per Östlund	"Please check [https://libraries.openmodelica.org/branches/newInst/Modelica_trunk/files Modelica.Media.Examples.MixtureGases]. The following error is reported
{{{
[OMCompiler/Compiler/BackEnd/Differentiate.mo:402:3-402:155:writable] Error:
Derivative of expression ""medium1.h = Modelica.Media.Examples.MixtureGases.Medium1.h_TX(medium1.T, {0.8, 0.2}, true, Modelica.Media.Interfaces.Choices.ReferenceEnthalpy.ZeroAt0K, 0.0)"" w.r.t. ""time"" is non-existent.
}}}
Upon inspection of the {{{Modelica.Media.Examples.MixtureGases.Medium1.h_TX}}} function, the algorithm when flattening with the OF is
{{{
 h := X[1] * Modelica.Media.IdealGases.Common.Functions.h_T(Modelica.Media.IdealGases.Common.DataRecord(""N2"", 0.0280134, 0, 309498.4543111511, 1000, {22103.71497, -381.846182, 6.08273836, -0.00853091441, 1.384646189e-005, -9.62579362e-009, 2.519705809e-012}, {710.846086, -10.76003744}, {587712.406, -2239.249073, 6.06694922, -0.00061396855, 1.491806679e-007, -1.923105485e-011, 1.061954386e-015}, {12832.10415, -15.86640027}, 296.8033869505308), T, exclEnthForm, refChoice, h_off) + X[2] * Modelica.Media.IdealGases.Common.Functions.h_T(Modelica.Media.IdealGases.Common.DataRecord(""O2"", 0.0319988, 0, 271263.4223783392, 1000, {-34255.6342, 484.700097, 1.119010961, 0.00429388924, -6.83630052e-007, -2.0233727e-009, 1.039040018e-012}, {-3391.45487, 18.4969947}, {-1037939.022, 2344.830282, 1.819732036, 0.001267847582, -2.188067988e-007, 2.053719572e-011, -8.193467050000001e-016}, {-16890.10929, 17.38716506}, 259.8369938872708), T, exclEnthForm, refChoice, h_off);
}}}
while the NF reports
{{{
  h := X * array(Modelica.Media.IdealGases.Common.Functions.h_T({Modelica.Media.IdealGases.Common.DataRecord(""N2"", 0.0280134, 0.0, 309498.4543111511, 1000.0, {22103.71497, -381.846182, 6.08273836, -0.00853091441, 1.384646189e-005, -9.62579362e-009, 2.519705809e-012}, {710.846086, -10.76003744}, {587712.406, -2239.249073, 6.06694922, -0.00061396855, 1.491806679e-007, -1.923105485e-011, 1.061954386e-015}, {12832.10415, -15.86640027}, 296.8033869505308), Modelica.Media.IdealGases.Common.DataRecord(""O2"", 0.0319988, 0.0, 271263.4223783392, 1000.0, {-34255.6342, 484.700097, 1.119010961, 0.00429388924, -6.83630052e-007, -2.0233727e-009, 1.039040018e-012}, {-3391.45487, 18.4969947}, {-1037939.022, 2344.830282, 1.819732036, 0.001267847582, -2.188067988e-007, 2.053719572e-011, -8.193467050000001e-016}, {-16890.10929, 17.38716506}, 259.8369938872708)}[i], T, exclEnthForm, refChoice, h_off) for i in 1:2);
}}}
I understand the fact that there is still an unexpanded {{{array()}}} operator probably explains the failure to differentiate the function."	defect	closed	high	2.0.0	New Instantiation		fixed