# Qalculate! – 旗舰级桌面计算器

Qalculate! is a multi-purpose cross-platform desktop calculator. It is simple to use but provides power and versatility normally reserved for complicated math packages, as well as useful tools for everyday needs (such as currency conversion and percent calculation). Features include a large library of customizable functions, unit calculations and conversion, physical constants, symbolic calculations (including integrals and quations), arbitrary precision, uncertainty propagation, interval arithmetic, plotting, and a user-friendly interface (GTK+ and CLI).

Qalculate! is free software, licensed under the GNU Public License v2 (or later).

#### Math Library

• Calculation and parsing:
• Basic operations and operators: + – * / mod ^ E () && || ! < > >= <= != ~ & | << >> xorFault-tolerant parsing of strings: log 5 / 2 .5 (3) + (2( 3 +5 = ln(5) / (2.5 * 3) + 2 * (3 + 5)Expressions may contain any combination of numbers, functions, units, variables, vectors and matrices, and datesSupports complex and infinite numbersPropagation of uncertaintyInterval arithmeticSupports all common number bases, as well as negative and non-integer radices, sexagesimal numbers, time format, and roman numeralsAbility to disable functions, variables, units or unknown variables for less confusion: e.g. when you do not want (a+b)^2 to mean (are+barn)^2 but (“a”+”b”)^2Customizable implicit multiplicationMatrices and vectors, and related operations (determinants etc.)Verbose error messagesArbitrary precisionRPN mode
Result display:
• Supports all common number bases, as well as negative and non-integer radices, sexagesimal numbers, time format, and roman numeralsMany customization options: precision, max/min decimals, complex form, multiplication sign, etc.Exact or approximate: sqrt(32) returns 4 * sqrt(2) or 5.66Simple and mixed fractions: 4 / 6 * 2 = 1.333… = 4/3 = 1 + 1/3
Symbolic calculation:
• E.g. (x + y)^2 = x^2 + 2xy + y^2; 4 “apples” + 3 “oranges”Factorization and simplificationDifferentiation and integrationCan solve most equations and inequalitiesCustomizable assumptions give different results (e.g. ln(2x) = ln(2) + ln(x) if x is assumed positive)
Functions:
• Hundreds of flexible functions: trigonometry, exponents and logarithms, combinatorics, geometry, calculus, statistics, finance, time and date, etc.Can easily be created, edit and saved to a standard XML file
Units:
• Supports all SI units and prefixes (including binary), as well as imperial and other unit systemsAutomatic conversion: ft + yd + m = 2.2192 mExplicit conversion: 5 m/s to mi/h = 11.18 miles/hourSmart conversion: automatically converts 5 kg*m/s^2 to 5 NCurrency conversion with retrieval of daily exchange ratesDifferent name forms: abbreviation, singular, plural (m, meter, meters)Can easily be created, edited and saved to a standard XML file
Variables and constants:
• Basic constants: pi, e, etc.Lots of physical constants (with or without units) and properties of chemical elementCSV file import and exportCan easily be created, edited and saved to a standard XML fileFlexible – may contain simple numbers, units, or whole expressionsData sets with objects and associated properties in database-like structure
Plotting:
• Uses GnuplotCan plot functions or data (matrices and vectors)Ability to save plot to PNG image, postscript, etc.Several customization options
and more…
The manual includes a complete list of included functionsunits, and variables, and some examples.