{ "cells" : [ { "cell_origin" : "client", "cell_type" : "latex", "cells" : [ { "cell_origin" : "client", "cell_type" : "latex_view", "source" : "\\algorithm{vary}{Generic variation algorithm for functional derivatives.}\n\nGeneric variation command. Takes a rule or a set of rules\naccording to which the terms in a sum should be varied. In every term,\napply the rule once to every factor." } ], "hidden" : true, "source" : "\\algorithm{vary}{Generic variation algorithm for functional derivatives.}\n\nGeneric variation command. Takes a rule or a set of rules\naccording to which the terms in a sum should be varied. In every term,\napply the rule once to every factor." }, { "cell_origin" : "client", "cell_type" : "input", "cells" : [ { "cell_origin" : "server", "cell_type" : "latex_view", "source" : "\\begin{dmath*}{}A B%\n+A C\\end{dmath*}" }, { "cell_origin" : "server", "cell_type" : "latex_view", "source" : "\\begin{dmath*}{}\\epsilon D B%\n+A \\epsilon C%\n+\\epsilon D C%\n+A \\left(\\epsilon A%\n-\\epsilon B\\right)\\end{dmath*}" } ], "source" : "ex:= A B + A C;\n\nvary(_, $A -> \\epsilon D, B -> \\epsilon C, C -> \\epsilon A - \\epsilon B$ );" }, { "cell_origin" : "client", "cell_type" : "latex", "cells" : [ { "cell_origin" : "client", "cell_type" : "latex_view", "source" : "It also works when acting on powers, in which case it will use the\nproduct rule to expand them." } ], "hidden" : true, "source" : "It also works when acting on powers, in which case it will use the\nproduct rule to expand them." }, { "cell_origin" : "client", "cell_type" : "input", "cells" : [ { "cell_origin" : "server", "cell_type" : "latex_view", "source" : "\\begin{dmath*}{}A^{3}\\end{dmath*}" }, { "cell_origin" : "server", "cell_type" : "latex_view", "source" : "\\begin{dmath*}{}3A^{2} \\delta\\left(A\\right)\\end{dmath*}" } ], "source" : "ex:= A**3;\nvary(_, $A -> \\delta{A}$);" }, { "cell_origin" : "client", "cell_type" : "latex", "cells" : [ { "cell_origin" : "client", "cell_type" : "latex_view", "source" : "This algorithm is thus mostly intended for variational derivatives." } ], "hidden" : true, "source" : "This algorithm is thus mostly intended for variational derivatives." }, { "cell_origin" : "client", "cell_type" : "input", "cells" : [ { "cell_origin" : "server", "cell_type" : "latex_view", "source" : "\\begin{dmath*}{}\\text{Attached property PartialDerivative to~}\\partial{\\#}.\\end{dmath*}" }, { "cell_origin" : "server", "cell_type" : "latex_view", "source" : "\\begin{dmath*}{}-\\int{}\\left(\\partial_{\\mu}{\\phi} \\partial^{\\mu}{\\phi}%\n+m^{2} \\phi^{2}\\right)\\, {\\rm d}x\\end{dmath*}" } ], "source" : "\\partial{#}::PartialDerivative;\nex:= -\\int{\\partial_{\\mu}{\\phi} \\partial^{\\mu}{\\phi} + m**2 \\phi**2}{x};" }, { "cell_origin" : "client", "cell_type" : "input", "cells" : [ { "cell_origin" : "server", "cell_type" : "latex_view", "source" : "\\begin{dmath*}{}-\\int{}\\left(\\partial_{\\mu}{\\delta\\left(\\phi\\right)} \\partial^{\\mu}{\\phi}%\n+\\partial_{\\mu}{\\phi} \\partial^{\\mu}{\\delta\\left(\\phi\\right)}%\n+2m^{2} \\phi \\delta\\left(\\phi\\right)\\right)\\, {\\rm d}x\\end{dmath*}" } ], "source" : "vary(ex, $\\phi -> \\delta{\\phi}$);" }, { "cell_origin" : "client", "cell_type" : "input", "cells" : [ { "cell_origin" : "server", "cell_type" : "latex_view", "source" : "\\begin{dmath*}{}-\\int{}\\left(-\\delta\\left(\\phi\\right) \\partial_{\\mu}\\,^{\\mu}{\\phi}%\n-\\partial^{\\mu}\\,_{\\mu}{\\phi} \\delta\\left(\\phi\\right)%\n+2m^{2} \\phi \\delta\\left(\\phi\\right)\\right)\\, {\\rm d}x\\end{dmath*}" } ], "source" : "integrate_by_parts(ex, $\\delta{\\phi}$);" }, { "cell_origin" : "client", "cell_type" : "input", "cells" : [ { "cell_origin" : "server", "cell_type" : "latex_view", "source" : "\\begin{dmath*}{}-\\int{}\\left(-2\\delta\\left(\\phi\\right) \\partial^{\\mu}\\,_{\\mu}{\\phi}%\n+2\\delta\\left(\\phi\\right) \\phi m^{2}\\right)\\, {\\rm d}x\\end{dmath*}" } ], "source" : "canonicalise(_)\nsort_product(_);" }, { "cell_origin" : "client", "cell_type" : "input", "cells" : [ { "cell_origin" : "server", "cell_type" : "latex_view", "source" : "\\begin{dmath*}{}-\\int{}\\delta\\left(\\phi\\right) \\left(-2\\partial^{\\mu}\\,_{\\mu}{\\phi}%\n+2\\phi m^{2}\\right)\\, {\\rm d}x\\end{dmath*}" } ], "source" : "factor_out(_, $\\delta{\\phi}$);" }, { "cell_origin" : "client", "cell_type" : "input", "source" : "" } ], "description" : "Cadabra JSON notebook format", "version" : 1 }