The Datafile PD-CD 1 Issue 2

home *** CD-ROM | disk | FTP | other *** search

/ The Datafile PD-CD 1 Issue 2 / PDCD-1 - Issue 02.iso / _utilities / utilities / 004 / _rpncalc / !RPNCalc / !Help < prev next >

Wrap

Text File | 1994-11-13 | 36KB | 951 lines

->!Help RPN Scientific Calculator ========================= This disc contains a powerful Scientific Calculator using Reverse Polish Notation for RISC OS on the Archimedes. The contents of this disc, are as follows; !Boot *Run by the Filer when it first displays the RPNCalc directory. !Sprites Passed to *IconSprites by the !Boot file. !Run *Run by the Filer when a user double-clicks on the RPNCalc directory. !RunImage RPNCalc executable code. Templates Window templates. Sprites RPNCalc private sprite file. Messages Text messages. !Help Information about RPNCalc. Choices User choices. Memory Requirements =================== Program Area 128K Limitations =========== RPNCalc only works under RISC OS 3.10 or greater. 1.0 Getting Started =================== To copy this application onto another disc, or install it on the hard disc, open a directory display on the destination disc within the RISC OS Desktop and drag the !RPNCalc application icon to the destination directory in the normal manner. The calculator may be installed on the icon bar by double clicking on the !RPNCalc application icon. Double-clicking on the !RPNCalc icon on the icon bar then causes the main calculator window to be displayed. This implements the numerical keyboard, display and simple arithmetic functions of the calculator. Further functions may be accessed through the pop-up menu associated with the calculator window. The calculator window may be removed from the screen area in the normal way by clicking on the close icon. The icon remains on the icon bar and the calculator's state and registers are maintained. Choice of the 'quit' item on the icon bar menu causes !RPNCalc to close all its windows and quit. RPNCalc is fully compatible with the !Help application. 2.0 Introduction ================ This calculator uses a unique operating logic based on that pioneered in the handheld calculator market by Clive Sinclair and for many years the basis of operation for the Hewlett-Packard range of calculators beloved by scientists and engineers. This differs from the logic used in most other calculators and centres around use of the ENTER button. This makes nested and complicated calculations easier and faster to work out. For example consider arithmetic functions. To perform arithmetic, key in the first number, click on ENTER to separate the first number from the second, then key in the second number and click on '+', '-', '*', or '/'. The result then appears immediately on the display. Try the following examples for yourself. To Compute: Buttons pressed Display 9 - 6 = 3 '9' 'ENTER' '6' '-' 3.00 9 x 6 = 54 '9' 'ENTER' '6' '*' 54.00 9 / 6 = 1.5 '9' 'ENTER' '6' '/' 1.50 3.0 Basic Operation =================== The calculator supports the entry of numbers and the operation of simple arithmetic functions through the clicking of the Select button on icons displayed within the main calculator window. The icons 0 to 9 and . allow numbers to be entered into the display. The icons + - / and * cause the corresponding arithmetical operations to be actioned. The ENTER icon terminates entry of a number. The CLR icon allows numbers to be deleted from the display. During number entry clicking on the CLR icon causes the last digit entered to be deleted. After number entry has been terminated clicking on CLR causes the entered number to be cleared. The CHS icon allows the sign of the displayed number to be changed. The EXP icon allows exponents to be entered. First enter the mantissa, then click on EXP and enter the exponent. For a negative exponent click on CHS after entering the exponent. The STO and RCL icons allow operation with the 10 internal storage registers. The x▓ icon calculates the square of the number in the display. The 1/x icon calculates the reciprocal of the number in the display. Further functions may be operated by clicking of the Adjust button on the icons in the main calculator window. The + icon accumulates statistical information within the storage registers R2 through R7. The - icon allows data to be removed from the accumulated statistical information. The ENTER icon rolls the memory stack down. The CLR icon causes the entire number in the display to be cleared. The x▓ icon calculates the square root of the number in the display. The Archimedes keyboard can also be used to control the calculator when the calculator has the input focus: The numeric keys 0 to 9 and . allow numbers to be entered into the display. The keys + - / and * cause the corresponding arithmetical operations to be actioned. Enter and Return have the same action as the 'ENTER' key on the calculator. The up and down arrow keys cause the register stack to roll up and down respectively. The pop-up menu provides access to more complex functions. The Function menu option provides access to simple one and two number arithmetic functions. The Effect menu option allows control of the display and trigonometric modes. The Utilities menu option provides access to transcendental, statistical and conversion functions as well as a range of constants. 3.1 Icon Bar Menu ================= Pressing Menu over the RPNCalc icon on the icon bar calls up the RPNCalc icon bar menu in the normal manner, this contains the following three items. Info details information about the program Choices allows the user to set choices that may be preserved from one use of RPNCalc to the next. The choices available are described in more detail in the following section. Quit causes the calculator windows to be closed and the dynamic memory to be freed. 3.2 User Choices ================ The Choices dialogue box is displayed by clicking on the Choices item in the icon bar menu and provides the following options. Register Display:- The Memory Stack Option causes the four memory stack registers to be displayed in a window. This allows the operation of the stack to be observed during use of the calculator. The Storage Option causes the ten internal storage registers to be displayed in a window. This allows operations between the calculator display and storage registers to be achieved by use of the Wimp's drag and drop features. The Startup Option causes the calculator and chosen register windows to be displayed immediately when RPNCalc is installed on the icon bar. Save saves the choices in the Choices file to be reused in subsequent sessions and implements the choices immediately. Cancel reset the choices in use before the dialogue box was displayed. Set implements the choices for the current session. 3.3 Import and Export of Values =============================== Results from the display and the displayed storage registers can be exchanged with other application windows using the drag and drop features of the WIMP. 3.3.1 Import A value can be entered into the calculator by dropping the sprite for a selected save of numerical text from another application into the calculator display or a displayed storage register. If the sprite is dropped over the display then the dragged text will be entered into the calculator as though it has been typed in at the keyboard. If the sprite is dropped over a storage register then the value is entered into the register as though it had been entered into the display and then stored in the register. 3.3.2 Export The value from the display may be transferred to another application by pressing select over the display, dragging the resulting sprite to the intended window and releasing select. The value from a storage register may also be transferred by pressing Select over the required storage register in the storage register window, dragging the resulting sprite to the intended window and releasing Select. RPNCalc then attempts to place the text icon in the intended window and insert the text string corresponding to the dragged value. 3.3.3 Calculation The calculator can also accept input from a text file. This may include both values and functions. These will be entered into the calculator as though entered through the calculator window or computer keyboard. A carriage return actions the ENTER functions and the simple arithmetic functions, '-', '+', 'x', and '/' are supported. For example, if an ASCII text file is prepared with the contents, 1.25 2.5 + and the file is dragged to the calculator window then both numbers will be entered into the calculator and the '+' operation executed to give result, 3.75 4.0 Numeric Functions ===================== This section discusses the numeric functions of RPNCalc available from the pop-up menu. Several of these functions are also available using the calculator icons or the computer's keyboard. 4.1 Constants ------------- The choice of UtilitiesëConstants causes the Physical Constants dialogue box to be displayed, this contains a vertical list of common physical constants. Choice of an item from the list causes the chosen constant to be entered into the calculator. 4.2 Number Alteration Functions ------------------------------- UtilitiesëAlterationëInteger replaces the number in the display with the nearest integer of lesser or equal magnitude. UtilitiesëAlterationëFraction replaces the number in the display with its fractional part (the difference between the number and its integer part). UtilitiesëAlterationëRound rounds all 18 internally held digits of the mantissa of the displayed value to the number of digits specified by the current display format. UtilitiesëAlterationëAbsolute yields the absolute value of the number in the display. 4.3.0 One-Number Functions -------------------------- 4.3.1 General Functions Choice of the option Functionsë1/x calculates the reciprocal of the number in the display. Choice of the option Functionsëx! calculates the factorial of the displayed value, where x is an integer between 0 and 69. x! can also be used to calculate the Gamma function, in this case x is not restricted to non-negative numbers. x! actually calculates Gamma( x+1 ). Choice of the option Functionsësqrt x calculates the positive square root of the number in the display. Choice of the option Functionsëx▓ calculates the square of the number in the display. 4.3.2 Trigonometric Operations 4.3.2.1 Trigonometric Modes The trigonometric functions operate in trigonometric modes selected by the user. The trigonometric mode tells the calculator what unit of measure (degrees, radians or grads) to assign a number for a trigonometric function. Choice of the EffectëMode pop-up menu option causes the trigonometric mode dialogue box to be displayed allowing the mode to be applied to the calculator. Degrees sets Degrees mode. No annunciator appears in the display. This is the mode on initialisation. Radians sets Radians mode. The RAD annunciator appears in the display. Grads sets Grads mode. The GRAD annunciator appears in the display. 4.3.2.2 Trigonometric Functions Option Chosen Function UtilitiesëFunctionsëCircularësinh x sine of x UtilitiesëFunctionsëCircularëasinh x arc sine of x UtilitiesëFunctionsëCircularëcosh x cosine of x UtilitiesëFunctionsëCircularëacosh x arc cosine of x UtilitiesëFunctionsëCircularëtanh x tangent of x UtilitiesëFunctionsëCircularëatanh x arc tangent of x Before executing a trigonometric function be sure that the calculator is set to the desired trigonometric mode. 4.3.3 Time and Angle Conversions Numbers representing time (hours) or angles (degrees) can be converted by the calculator between a decimal-fraction and a minutes-second format. Choice of the UtilitiesëConversionsëH.MS option converts the number in the display from a decimal format to a minutes-second format. Choice of the UtilitiesëConversionsëHours option converts the number in the display from a minutes-second format to a decimal format. 4.3.4 Degrees and Radians Conversions Number representing angles can be converted between degrees and radians. The angles must be expressed in decimal numbers and not in minutes-second format. Choice of the UtilitiesëConversionsëDegrees option converts the number in the display to degrees. Choice of the UtilitiesëConversionsëRadians option converts the number in the display to radians. 4.3.5 Logarithmic Functions Choice of the 'UtilitiesëFunctionsëLogarithmicëLN x' option calculates the natural logarithm of the number in the display; that is, the logarithm to the base e. Choice of the 'UtilitiesëFunctionsëLogarithmicëe^x' option calculates the natural antilogarithm of the number in the display; that is, raises e to the power of that number. Choice of the 'UtilitiesëFunctionsëLogarithmicëLOG x' option calculates the common logarithm of the number in the display; that is, the logarithm to the base 10. Choice of the 'UtilitiesëFunctionsëLogarithmicë10^x' option calculates the common antilogarithm of the number in the display; that is, raises 10 to the power of that number. 4.3.6 Hyperbolic Functions Option Chosen Function UtilitiesëFunctionsëHyperbolicësinh x hyperbolic sine of x UtilitiesëFunctionsëHyperbolicëasinh x inverse hyperbolic sine of x UtilitiesëFunctionsëHyperbolicëcosh x hyperbolic cosine of x UtilitiesëFunctionsëHyperbolicëacosh x inverse hyperbolic cosine of x UtilitiesëFunctionsëHyperbolicëtanh x hyperbolic tangent of x UtilitiesëFunctionsëHyperbolicëatanh x inverse hyperbolic tangent of x 4.4.0 Two-Number Functions -------------------------- The calculator performs two-number functions using two values entered sequentially into the display. If these numbers are keyed in then they must be separated by ENTER or any other function that terminates digit entry. For a two-number function, the first value entered is considered the y-value because it is placed into the Y-register for memory storage. The second value entered is considered the x-value because it remains in the display, which is the X-register. The arithmetic operators, +, -, * and /, are the four basic two-number functions. Others are given below. 4.4.1 The Power Function Choice of the Functionsëy^x option calculates the value of y raised to the x power. The base number, y, is keyed in before the exponent, x. 4.4.2 Percentages The percentage functions preserve the value of the original base number along with the result of the percentage calculation. This allows subsequent calculations to be carried out using the base number and the result without re-entering the base number. 4.4.2.1 Percent Choice of the 'Functionsëx% of y' option calculates the specified percentage, x, of a base number, y. 4.4.2.2 Percent Difference Choice of the 'Functionsë(x-y)% of y' option calculates the percent difference between two numbers. The result expresses the relative increase (a positive result) or decrease (a negative result) of x compared to y. 4.4.3 Polar and Rectangular Coordinate Conversions These functions are provided for conversions between polar and rectangular coordinates. The angle 'theta' is assumed to be in the units set by the current trigonometric mode, whether degrees (in decimal format), radians or grads. 4.4.3.1 Polar Conversion Choice of the UtilitiesëConversionsëPolar option converts a set of rectangular coordinates (x, y) to polar coordinates (magnitude r, angle theta). The y-value must be entered first, the x-value second. Upon execution r will appear in the display. Choose the 'Functionsëx<>y' option (X exchange Y) to bring theta out of the Y-register and into the display. Theta will be returned as a value between -180░ and 180░, between -PI and PI radians, or between -200 and 200 grads. 4.4.3.2 Rectangular Conversion Choice of the UtilitiesëConversionsëRectangular option converts a set of polar coordinates (r, theta) to rectangular coordinates (x, y). Theta must be entered first, then r. Upon execution x will appear in the display. Choose the 'Functionsëx<>y' option to display y. 5.0 The Automatic Memory Stack and Data Storage =============================================== 5.1 The Automatic Memory Stack and Stack Manipulation ----------------------------------------------------- The calculator's operating logic is based on a mathematical logic known as 'Polish Notation'. Conventional algebraic notation places the algebraic operators between the relevant numbers or variables when evaluating algebraic expressions. 'Polish Notation' specifies the operators before the variables. The calculator uses the convention, applied by Hewlett Packard for efficiency of use, of specifying the operators after the variables. Hence the term 'Reverse Polish Notation' (RPN). RPNCalc uses RPN to solve complicated calculations in a straightforward manner, without parentheses or punctuation. It does so by automatically retaining and returning intermediate results. This system is implemented through the automatic memory stack and the ENTER function, minimising total operations. The number that appears in the display is the X-register. Any number that is keyed in or results from the execution of a numeric function is placed into the display (X-register). This action will cause numbers already in the stack to lift, remain in the same register, or drop, depending upon both the immediately preceding and the current operation. Numbers in the stack are stored on a last-in, first-out basis. For convenience the registers are named X, Y, Z and T. The number in the T-register remains there when the stack drops, allowing this number to be used repetitively as an arithmetic constant. 5.1.1 Stack Display Selection of the Memory Stack Option in the Choices dialogue box allows the four stack registers to be displayed in a window. 5.1.2 Stack Manipulation Functions Clicking on ENTER separates two numbers keyed in one after the other. It does so by lifting the stack and copying the number in the display (X-register) into the Y-register. The next number entered then writes over the value in the X-register; there is no stack lift. The up and down arrow keys on the computer keyboard roll the contents of the stack registers up and down one register (one value moves between the X and the T-register). No values are lost. Clicking of the ADJUST button on the ENTER icon also rolls the register stack down. Choice of the Functionsëx<>y pop-up menu option exchanges the numbers in the X and Y-registers. 5.1.3 The LAST X Register The LAST X register is a separate memory register which preserves the value that was last in the display before execution of a numeric operation. Choice of the 'UtilitiesëLAST X' pop-up menu option places a copy of the contents of the LAST X register into the display. The LAST X feature avoids the re-entry of numbers needed again. It can also assist in error recovery, such as executing the wrong function or keying in the wrong number. 5.1.4 Calculator Functions and the Stack When two numbers are entered, one after the other, ENTER is operated between entries. However ENTER does not need to be used when a number is immediately followed by a function. This is because most functions enable lifting of the stack, such that the stack will lift automatically when the next number is keyed or recalled into the display, and terminates digit entry, so that the next number starts a new entry. There are four functions - ENTER, CLx, SUM+ and SUM- - that disable stack lift. Following execution of one of these functions a new number will write over the currently displayed number instead of causing the stack to lift. In most cases the effects are natural. 5.1.5 Order of Entry and the ENTER key An important aspect of two-number functions is the positioning of the numbers in the stack. To execute an arithmetic function, the numbers should be positioned in the stack in the same way that they are vertically positioned on paper. For example: 98 98 98 98 -15 +15 x15 /15 --- --- --- --- The first (or top) number would be in the Y-register, while the second (or bottom) number would be in the X-register. When the mathematical operation is performed, the stack drops, leaving the result in the X-register. 5.1.6 Nested Calculations The automatic stack lift and stack drop make it possible to do nested calculations without using parentheses or storing intermediate results. A nested calculation is solved simply as a series of one and two-number operations. Almost every nested calculation can be done using just the four stack registers. It is usually wisest to begin the calculation at the innermost number or pair of parentheses and work outwards (as for a manual calculation). Otherwise an intermediate result may need to be placed in a storage register. For example, consider the calculation of 3 ( 4 + 5 ( 6 + 7 ) ) : Entries Display 6 ENTER 7 + 13.00 Intermediate result of ( 6 + 7 ). 5 x 65.00 Intermediate result of 5 ( 6 + 7 ). 4 + 69.00 Intermediate result of ( 4 + 5 ( 6 + 7 ) ). 3 x 207.00 Final result: 3 ( 4 + 5 ( 6 + 7 ) ). The stack automatically drops after each two-number calculation, and then lifts when a new number is keyed in. 5.1.7 Arithmetic Calculations with Constants There are three ways (without using a storage register) to manipulate the memory stack to perform repeated calculations with a constant: 1. Use the LAST X register 2. Load the stack with a constant and operate upon different numbers. 3. Load the stack with a constant and operate upon an accumulating numbers. 5.1.7.1 LAST X Enter the constant second so that it will be saved in the LAST X register. Choice of the 'UtilitiesëLAST X' pop-up menu option will place a copy of the contents of the LAST X register into the X-register (the display). This can be done repeatedly. 5.1.7.2 Loading the Stack with a Constant Because the number in the T-register is replicated when the stack drops, this number can be used as a constant in arithmetic operations. Fill the stack with a constant by entering it into the display and clicking on ENTER three times. Enter the initial argument and perform the arithmetic operation. The stack will drop, a copy of the constant will "fall" into the Y-register, and a new copy of the constant will be generated in the T-register. If the variables change be sure to clear the display before entering the new variable. This disables the stack so that the arithmetic result will be written over and only the constant will occupy the rest of the stack. If the operation is to be performed on a cumulative number, then do not clear the display - simply repeat the arithmetic operation. 5.2 Storage Register Operations ------------------------------- When numbers are stored or recalled, they are copied between the display (X-register) and the data storage registers. RPNCalc has 10 directly accessible storage registers: R0 through R9. Six registers, R2 to R7, are also used for statistics calculations. 5.2.1 Storage Register Display Setting of the Storage Option in the Choices dialogue box allows the ten storage registers to be displayed in a window. This allows storage register operations to be performed using the drag and drop features of the WIMP under RISC OS as well as simplifying the normal operations. On the left of each storage register is a radio button, this can be used to select a storage register. Only one storage register may be selected at any one time. Pressing Adjust over a selected radio button will deselect it such that no storage registers are selected. (This is a slight deviation from the RISC OS 3 Style Guide). 5.2.2 Storing and Recalling Numbers 5.2.2.1 Storing Numbers Clicking on the STO icon followed by a storage register address (0 through 9) copies the number from the display into the specified data storage register replacing the existing contents of that register. During this operation a STO annunciator appears in the display showing that a storage register address is required. If the storage register window is open and one of the storage registers has been selected then clicking on the STO icon will copy the number from the display into the selected data storage register without entry of the storage register address. The number from the display may also be transferred to a storage register by pressing Select over the display, dragging the resulting sprite to the required storage register in the storage register window and releasing Select. 5.2.2.2 Recalling Numbers Clicking on the RCL icon followed by a storage register address (0 through 9) copies the number from the specified data storage register into the display. The contents of the storage register remain unaltered. During this operation a RCL annunciator appears in the display showing that a storage register address is required. If the storage register window is open and one of the storage registers has been selected then clicking on the RCL icon will copy the number from the selected data storage register into the display without entry of the storage register address. The number from a storage register may also be transferred to the display by pressing Select over the required storage register in the storage register window, dragging the resulting sprite to the display and releasing Select. 5.2.2.3 Exchanging Numbers If the storage register window is open then the number from a storage register may be exchanged with the display by pressing Select over the required storage register in the storage register window, dragging the resulting sprite to the display and releasing Select, while the SHIFT key is pressed. 5.2.3 Clearing Data Storage Registers This function has not been implemented. 5.2.4 Storage and Recall Arithmetic 5.2.4.1 Storage Arithmetic It is possible to perform arithmetic on a number in a storage register and store the result in the same register without use of the RCL operation. With the second operand in the display click on the STO icon followed by one of, +, -, x, or /. The STOn annunciator will appear in the display, where n is one of, +, -, x, or /. Finally key in the register address (0 to 9) by selecting the corresponding icon. The new number in the register is determined as follows. + new contents = old contents - number in of register of register x display / 5.2.4.2 Recall Arithmetic Recall arithmetic allows arithmetic with the displayed value and a stored value without lifting the stack, that is, without losing any values from the Y, Z and T-registers. With the second operand in the display click on the RCL icon followed by one of, +, -, x, or /. The RCLn annuncator will appear in the display, where n is one of, +, -, x, or /. Finally key in the register address (0 to 9) by selecting the corresponding icon. The new number in the register is determined as follows. + new display = old display - contents of x register / 5.2.4.3 Overflow and Underflow On underflow the calculate reports a 'Divide by zero' error and the register is unchanged. 6.0 Statistical Functions ========================= 6.1 Probability Calculations ---------------------------- The input for permutation and combination calculations is restricted to nonnegative integers. Enter the y-value before the x-value. These functions, like the arithmetic operators, cause the stack to drop as the result is placed in the X-register. 6.1.1 Permutations Choice of the UtilitiesëFunctionsëStatisticalëPxy pop-up menu option calculates the number of different arrangements of y different items taken in quantities of x items at a time. No item occurs more than once in an arrangement, and different order of the same x items in an arrangement are counted separately. The formula is y! Py,x = -------- (y - x)! 6.1.2 Combinations Choice of the UtilitiesëFunctionsëStatisticalëCxy pop-up menu option calculates the number of possible sets of y different items taken in quantities of x items at a time. No item occurs more than once in a set, and different order of the same x items in a set are not counted separately. The formula is y! Cy,x = ---------- x!(y - x)! 6.2 Random Number Generator --------------------------- Choice of the UtilitiesëFunctionsëStatisticalëRAN# pop-up menu option will generate a random number in the range 0 <= r < 1. 6.3 Accumulating Statistics --------------------------- RPNCalc performs one and two-variable statistical calculations through the use of the SUM+ and SUM- functions. The SUM+ function is executed by clicking on the + icon with the Adjust button. Similarly the SUM- function is executed by clicking on the - icon with the Adjust button. The data is first entered into the Y and X registers. Then the SUM+ function automatically calculates and stores statistics of the data in storage registers R2 through R7. These registers are therefore referred to as the statistics registers. Therefore before beginning to accumulate statistics for a new set of data ensure that the statistics registers and stack are clear. In one-variable statistical calculations, enter each data point (x-value) by keying in x and executing SUM+. In two-variable statistical calculations, enter each data pair (x and y-values) by keying by first keying in the y-value, clicking on ENTER, then keying in the x-value, and finally executing SUM+. The current number of accumulated data points, n, will be displayed. The x-value is saved in the LAST X register and y remains in the Y-register. SUM+ disables stack lift, so the stack will not lift when the next number is keyed in. The statistics of the data are compiled as follows: Register Contents R2 n Number of data points accumulated. R3 SUMx Summation of x-values. R4 SUMx▓ Summation of squares of x-values. R5 SUMy Summation of y-values. R6 SUMy▓ Summation of squares of y-values. R7 SUMxy Summation of products of x and y-values. Any of the accumulated statistics can be recalled to the display by clicking on RCL and the number of the data storage register containing the desired statistic. 6.3.1 Correcting Accumulated Statistics If data is entered incorrectly, the accumulated statistics can be easily corrected. Key the incorrect data pair into the Y and X-registers and execute SUM-, then key in the correct value for x and y and execute SUM+. Alternatively, it the incorrect data point or pair is the most recent one entered and SUM+ has been pressed, choosing the 'UtilitiesëLAST X' pop-up menu option and executing SUM- will remove the incorrect data. 6.3.1 Mean Choice of the UtilitiesëFunctionsëStatisticalëmean pop-up menu option calculates the arithmetic mean of the x and y values using the statistics accumulated in the relevant registers, the contents of the stack lift and the mean of x is copied into the X-register as the mean of y is copied into the Y-register. Choice of the 'Functionsëx<>y' pop-up menu option can be used to view the mean of y if the memory stack registers are not displayed. 6.3.2 Standard Deviation Choice of the UtilitiesëFunctionsëStatisticalësd pop-up menu option calculates the standard deviation of the accumulated statistics data. This function gives an estimate of the population standard deviation from the sample data, and is therefore termed the sample standard deviation. On execution the contents of the stack are lifted and the Sx is placed into the X-register as the Sy is placed into the Y-register. Choice of the 'Functionsëx<>y' pop-up menu option can be used to view Sy if the memory stack registers are not displayed. 6.3.3 Linear Regression This function has not been implemented. 6.3.4 Linear Estimation and Correlation Coefficient This function has not been implemented. 6.3.5 Other Applications 6.3.5.1 Vector Arithmetic The statistical accumulation functions can be used to perform vector addition and subtraction. Polar coordinates must be converted to rectangular coordinates upon entry. The results are available in R3 (Sum of x) and R5 (Sum of y) and may be converted back to polar coordinates, if necessary. For the second vector entered, the final function will be either SUM+ or SUM-, depending on whether the two vectors should be added or subtracted. 7.0 The Display =============== The calculator has three display formats - fixed decimal, scientific, and engineering - that may be specified using the Display Format dialogue box accessible from the EffectsëDisplay pop-up menu option. The current display format takes affect when digit entry is terminated; until then, all digits keyed in (up to 16) are displayed. 7.1 Fixed Decimal Display Fixed decimal format displays a figure with the number of decimal places specified (up to 10, depending on the size of the integer portion). Exponents will be displayed if the number is too small or too large for the display. 7.2 Scientific Notation Display Scientific format displays a figure in scientific notation with the number of decimal places specified (up to 10). In this mode exponents are displayed. 7.3 Engineering Notation Display Engineering format displays numbers in an engineering notation format in a manner similar to scientific, except that all exponents are shown in multiples of three. 7.4 Mantissa Regardless of the display format the calculator always internally holds each number as a 18 bit mantissa and a three bit exponent. 8.0 Limits ========== The calculator performs all internal mathematical calculations using double precision floating point numbers with limits as defined in the float.h header of ANSI C Release 4. 9.0 Known Bugs ============== Engineering mode display is the same as scientific mode. On the RiscPC the drop and drag functions appear to effect the anti-aliased fonts used by the WIMP. WIMP test appears to be changes back to the system font. The screen needs to be refreshed in order to recover the normal font. Detection of overflow is not good. Overflow can sometimes crash RPNCalc. ============================================================================= Release 1.00 November 1994 (c) Copyright Peter Tuson 1994 This product is distributed as public domain. It be reproduced in whole or part by any means without written permission of the author. While every care is taken, the author cannot be held responsible for any errors in this product, or for the loss of any data or consequential effects from the use of this package. RISC OS, RiscPC and Archimedes are trademarks of Acorn Computer Ltd. The source for constants and neumeric formulas was obtained from: Handbook of Mathematical Functions Edited by Abramowitz and Stegun published by Dover, SBN 0-486-61272-4 ====== If you find this program useful or interesting a donation of ú10 sterling, sent to the address below, would be much appreciated. If you have any comments, suggestions, more bug reports or complaints, please write to the following address. This does not constitute a commitment to correct reported bugs. Dr. P.R.Tuson 70, Connaught Road Fleet Hants. GU13 9QY United Kingdom.