# Editing Symbolic package

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− | The {{Forge|symbolic|symbolic package}} is part of the | + | The {{Forge|symbolic|symbolic package}} is part of the octave-forge project. |

− | [[Category:Octave Forge]] | + | [[Category:Octave-Forge]] |

=== Demos and usage examples === | === Demos and usage examples === | ||

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</source> | </source> | ||

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<source lang="octave"> | <source lang="octave"> | ||

− | ## The following code will produce the same vector field plot as Figure 1.14 from Example 1.6 (pg. 39) from A Student's Guide to Maxwell's Equations by Dr. Daniel Fleisch. | + | ##Demo of how to graph symbolic functions (by converting SYMBOLIC functions into ANONYMOUS functions) |

+ | ##The following code will produce the same vector field plot as Figure 1.14 from Example 1.6 (pg. 39) from A Student's Guide to Maxwell's Equations by Dr. Daniel Fleisch. | ||

− | ## Make sure symbolic package is loaded and symbolic variables declared. | + | ##Make sure symbolic package is loaded and symbolic variables declared. |

− | pkg load symbolic | + | pkg load symbolic; |

syms x y | syms x y | ||

− | ## Write a Vector Field Equation in terms of symbolic variables | + | ##Write a Vector Field Equation in terms of symbolic variables |

− | + | vector = [sin(pi .* y ./2 ); -sin(pi .* x ./2 )]; | |

− | ## Vector components are converted from | + | ##Vector components are converted from symoblic into anonymous form which allows them to be graphed |

− | ## The "'vars', [x y]" syntax | + | ##The '1' & '2', in vector(1) & vector(2) are indeces for the vector. |

− | iComponent = function_handle ( | + | ##The " 'vars', [x y]" syntax tells function_handle that each component is a function of both 'x' & 'y' |

− | jComponent = function_handle ( | + | iComponent = function_handle (vector(1), 'vars', [x y]); |

+ | jComponent = function_handle (vector(2), 'vars', [x y]); | ||

− | ## | + | ##Setting the Grid up to graph all axes for all variables from -.5 to .5, with spacings .05 apart. |

− | [X,Y] = meshgrid ([- | + | [X,Y] = meshgrid([-.5:.05:.5]); |

+ | ##Draw the Vector Field! | ||

figure | figure | ||

− | quiver (X, Y, iComponent (X, Y), jComponent (X,Y)) | + | quiver(X,Y,iComponent(X,Y),jComponent(X,Y)) |

</source> | </source> | ||

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## | ## | ||

syms y(x) | syms y(x) | ||

− | + | de =diff(y, 3 ) +sqrt(2)*diff(y,2) + diff(y) == 0; | |

− | de =diff(y, 3 ) + | ||

f = dsolve(de, y(0) == 0, diff(y,1)(0) == 0 , diff(y,2)(0) == 1) | f = dsolve(de, y(0) == 0, diff(y,1)(0) == 0 , diff(y,2)(0) == 1) | ||

ff=function_handle(rhs(f)) | ff=function_handle(rhs(f)) |