physics-materialderivative.sty

physics-materialderivative.sty

\RequirePackage{xparse}

\DeclareDocumentCommand\materialderivative{ s o g d() }
{ % Total materialderivative
	% s: star for \flatfrac flat materialderivative
	% o: optional n for nth materialderivative
	% g: optional (f in df/dx)
	% d: long-form d/dx(...)
	\IfBooleanTF{#1}
	{\let\fractype\flatfrac}
	{\let\fractype\frac}
	\IfNoValueTF{#3}
	{
		\IfNoValueTF{#4}
		{\fractype{\mathrm{D} \IfNoValueTF{#2}{}{^{#2}}}{\mathrm{D} t\IfNoValueTF{#2}{}{^{#2}}}}
		{\fractype{\mathrm{D} \IfNoValueTF{#2}{}{^{#2}}}{\mathrm{D} t\IfNoValueTF{#2}{}{^{#2}}} \argopen(#4\argclose)}
	}
	{\fractype{\mathrm{D} \IfNoValueTF{#2}{}{^{#2}} #3}{\mathrm{D} t\IfNoValueTF{#2}{}{^{#2}}}}
}
\DeclareDocumentCommand\mdv{}{\materialderivative} % Shorthand for \materialderivative

\mdv{f} = \frac{\mathrm{D} f}{\mathrm{D} t}