Table of Contents

- Getting Started
- Panning and Zooming
- Equation Entry
- Calculations
- Function List
- Graph Settings
- About Graphite

- "Calculate" enters the calculation mode.
- "Recenter" moves the origin to the center of the screen.
- "Help" brings up this document.
- "Edit" brings up the "Parameters" screen, where you can modify equations and view settings.

If you press and drag a second finger, you can zoom in and out of the graph with a pinching gesture. You can choose to scale just the x axis, just the y axis, or both axes simultaneously. A gray crosshair or arrow will appear whenever two fingers are on the graph to indicate which zooming mode has been activated. The gestures are summarized in the table below:

Zoom Axis | Gesture |
---|---|

X-axis only |
Place second finger to form a horizontal line with the first finger. Move your fingers closer together along this line to contract the x-axis (zoom out), and move your fingers farther apart to expand (zoom in). |

Y-axis only |
Place second finger to form a vertical line with the first finger. Move your two fingers closer together along this line to contract the y-axis (zoom out), and move your fingers farther apart to zoom in. |

Both axes |
Place the second finger to form a diagonal line with the first finger. Decrease the horizontal and vertical distance between your fingers to contract the x- and y-axes respectively (zoom out). Increase the horizontal and vertical distance between your fingers to zoom in. |

If you would like to insert a new equation, first tap "Add, Remove, and Reorder," and then tap the green plus:

The equation entry screen appears differently in landscape mode and portrait mode, but the exact same functionality is present in both. There is a text field that displays the entered equation, and an array of convenience buttons:

There are also sliders that you can use to change the width and color of the equation's line.

When you change either the equation or properties of the equation, you can save your changes by pressing the save button in the upper right corner of the screen. If you do not want to keep your changes, press the back button labeled "Parameters" in the upper left corner of the screen. If there is an error with the equation you input, the save button will not save your changes and will instead bring up an error describing the problem. You can still press the back button to cancel your changes if you'd like.

If you would like to remove an equation, either swipe your finger across it horizontally and press the delete button that appears, or tap "Add, Remove, and Reorder," and tap the red minus next to the equation.

If you want to change the equations' drawing order, press "Add, Remove, and Reorder" and then drag the handle that appears to the right of each equation to move it to the desired location. (An equation appearing above another equation in the list means that it will graph on top of that other equation.) Graphite can compute many useful quantities using precise numeric methods. From the graph screen, press the "Calculate" button on the toolbar. A new toolbar will appear, along with an instruction bar at the top of the screen:

Description | |
---|---|

Trace Mode Find (x,y) pairs along a curve. | |

Root Finding Mode Find a curve's zeros. | |

Area/Integration Mode Find a definite integral numerically. | |

Extremum Finding Mode Find a minimum or maximum. | |

Intersect Finding Mode Find an intersection of two curves. | |

Exit Calculation Interface |

If at any time you want to change to a different curve or pair of curves for computation, press the computation button again and then select the new curve(s) desired.

The trace mode and area mode are the only exceptions to this process. In trace mode, you can drag your fingers along multiple curves. Trace points always stay along the curves that were nearest to where the original touch was made. In area mode, the integral is computed roughly as the integration bounds are changed, and more exactly when you let go. If an integral cannot be computed, the result will read "invalid approximation," and you will get an error message when you let go of the bounds. If an integral is undefined, but the numeric method does converge, the result will read "nan" or "inf." Here is a list of all the functions and operators that can be used to construct equations in Graphite.

Operator | Description |
---|---|

+ | Addition |

- | Subtraction/Negation |

* | Multiplication |

/ | Division |

^ | Exponentiation |

Function Name | Description |
---|---|

abs | Absolute Value |

sin | Sine |

cos | Cosine |

tan | Tangent |

csc | Cosecant |

sec | Secant |

cot | Cotangent |

sinh | Hyperbolic Sine |

cosh | Hyperbolic Cosine |

tanh | Hyperbolic Tangent |

asin | Arcsine |

acos | Arccosine |

atan | Arctangent |

asinh | Hyperbolic Arcsine |

acosh | Hyperbolic Arccosine |

atanh | Hyperbolic Arctangent |

log | Logarithm Base 10 |

ln | Natural Logarithm |

sqrt | Square Root |

ceil | Ceiling Function |

floor | Floor Function |

Tapping "Appearance Settings" will bring up switches to toggle the following options:

Setting | Purpose |
---|---|

Axes | Show/hide x and y axes. |

Tickmarks | Show/hide tickmarks. (Only allowed if axes are also shown.) |

Grid | Show/hide grid that appers on major tickmarks. (Only allowed if tickmarks are shown.) |

Labels | Show/hide number labels that appear on major tickmarks. (Only allowed if tickmarks are shown.) |

Changing Bounds | Show/hide numbers that appear at the screen edges while manipulating the graph viewing frame to indicate the current window bounds. |

Thanks go to Matt Czubakowski, Chris Dewan, Max Grazier G'sell, and Esther Wang for their bug testing and suggestions, and Robert Kaspar for his help with this documentation.

Please send any comments, suggestions, and bug reports to graphite@julianpanetta.com.

©2008 Julian Panetta